Bound states in the continuum (BICs) offer a promising solution to achieving high-quality factor (Q factor) cavities. However, finite-size effects severely deteriorate the BIC mode in practical applications. This pape...Bound states in the continuum (BICs) offer a promising solution to achieving high-quality factor (Q factor) cavities. However, finite-size effects severely deteriorate the BIC mode in practical applications. This paper reports the experimental demonstration of an electrically pumped 940 nm laser based on optimized BIC cavity, achieving a high Q factor of up to 1.18 × 10^(4) even with finite photonic crystal footprint, which is two orders of magnitude larger than un-optimized BIC design. Two strategies have been systematically investigated to mitigate finite-size effects: reflective photonic crystal cavity design and graded photonic crystal cavity design. Both methods significantly improve the Q factor, demonstrating the effectiveness of preserving BIC characteristics in finite-sized photonic crystal cavities. In addition, the reflective boundary photonic crystal design is fabricated and experimentally characterized to demonstrate its lasing characteristics. The fabricated laser exhibits single-mode operation with a signal-to-noise ratio of 38.6 dB. These results pave the way for future designs of BICs with finite size in real applications, promoting the performance of BIC-based integrated lasers.展开更多
Taking the advantage of ultrafast optical linear and nonlinear effects, all-optical signal processing(AOSP) enables manipulation, regeneration, and computing of information directly in optical domain without resorting...Taking the advantage of ultrafast optical linear and nonlinear effects, all-optical signal processing(AOSP) enables manipulation, regeneration, and computing of information directly in optical domain without resorting to electronics. As a promising photonic integration platform, silicon-on-insulator(SOI) has the advantage of complementary metal oxide semiconductor(CMOS) compatibility, low-loss, compact size as well as large optical nonlinearities. In this paper, we review the recent progress in the project granted to develop silicon-based reconfigurable AOSP chips, which aims to combine the merits of AOSP and silicon photonics to solve the unsustainable cost and energy challenges in future communication and big data applications. Three key challenges are identified in this project:(1) how to finely manipulate and reconfigure optical fields,(2) how to achieve ultra-low loss integrated silicon waveguides and significant enhancement of nonlinear effects,(3) how to mitigate crosstalk between optical, electrical and thermal components. By focusing on these key issues, the following major achievements are realized during the project. First, ultra-low loss silicon-based waveguides as well as ultra-high quality microresonators are developed by advancing key fabrication technologies as well as device structures. Integrated photonic filters with bandwidth and free spectral range reconfigurable in a wide range were realized to finely manipulate and select input light fields with a high degree of freedom. Second, several mechanisms and new designs that aim at nonlinear enhancement have been proposed, including optical ridge waveguides with reverse biased PIN junction, slot waveguides,multimode waveguides and parity-time symmetry coupled microresonators. Advanced AOSP operations are verified with these novel designs. Logical computations at 100 Gbit/s were demonstrated with self-developed, monolithic integrated programmable optical logic array. High-dimensional multi-value logic operations based on the four-wave mixing effect are realized. Multi-channel all-optical amplitude and phase regeneration technology is developed, and a multi-channel, multiformat, reconfigurable all-optical regeneration chip is realized. Expanding regeneration capacity via spatial dimension is also verified. Third, the crosstalk from optical as well as thermal coupling due to high-density integration are mitigated by developing novel optical designs and advanced packaging technologies, enabling high-density, small size, multi-channel and multi-functional operation with low power consumption. Finally, four programmable AOSP chips are developed, i.e.,programmable photonic filter chip, programmable photonic logic operation chip, multi-dimensional all-optical regeneration chip, and multi-channel and multi-functional AOSP chip with packaging. The major achievements developed in this project pave the way toward ultra-low loss, high-speed, high-efficient, high-density information processing in future classical and non-classical communication and computing applications.展开更多
Current study presents an advanced method for improving the visualization of subsurface blood vessels using laser speckle contrast imaging (LSCI), enhanced through principal component analysis (PCA) filtering. By comb...Current study presents an advanced method for improving the visualization of subsurface blood vessels using laser speckle contrast imaging (LSCI), enhanced through principal component analysis (PCA) filtering. By combining LSCI and laser speckle entropy imaging with PCA filtering, the method effectively separates static and dynamic components of the speckle signal, significantly improving the accuracy of blood flow assessments, even in the presence of static scattering layers located above and below the vessel. Experiments conducted on optical phantoms, with the vessel depths ranging from 0.6 to 2 mm, and in vivo studies on a laboratory mouse ear demonstrate substantial improvements in image contrast and resolution. The method’s sensitivity to blood flow velocity within the physiologic range (0.98-19.66 mm/s) is significantly enhanced, while its sensitivity to vessel depth is minimized. These results highlight the method’s ability to assess blood flow velocity independently of vessel depth, overcoming a major limitation of conventional LSCI techniques. The proposed approach holds great potential for non-invasive biomedical imaging, offering improved diagnostic accuracy and contrast in vascular imaging. These findings may be particularly valuable for advancing the use of LSCI in clinical diagnostics and biomedical research, where high precision in blood flow monitoring is essential.展开更多
Metal halide perovskites have become one of the most competitive new-generation optoelectronic materials due to their excellent optoelectronic properties. Vacuum evaporation can produce high-purity and large-area film...Metal halide perovskites have become one of the most competitive new-generation optoelectronic materials due to their excellent optoelectronic properties. Vacuum evaporation can produce high-purity and large-area films, leading to the wide application of this method in the semiconductor industry and optoelectronics field. However, the electroluminescent performance of vacuum-evaporated perovskite light-emitting diodes(PeLEDs) still lags behind those counterparts fabricated by solution methods. Herein, based on vacuum evaporation, 3D perovskite films are obtained by three-source co-evaporation.Considering the unique quantum well structure of quasi-2D perovskite can significantly enhance the exciton binding energy and improve the radiative recombination rate, leading to a high photoluminescence quantum yield(PLQY). Subsequently,the highly stable and low-defect-density quasi-2D perovskite is introduced into 3D perovskite films through post-treatment with phenethylammonium chloride(PEACl). To minimize the degradation of film quality caused by PEACl treatment, a layer of guanidinium bromide(GABr) is vacuum evaporated on top of PEACl treatment to further improve the quality of emitting layer. Finally, under the synergistic post-processing modification of PEACl and GABr, blue PeLEDs with a maximum external quantum efficiency(EQE) of 6.09% and a maximum brightness of 1325 cd/m^(2) are successfully obtained. This work deepens the understanding of 2D/3D heterojunctions and provides a new approach to construct PeLEDs with high performance.展开更多
The integration of machine learning with photonic and optoelectronic components is progressing rapidly, offering the potential for high-speed bio-inspired computing platforms. In this work, we employ an experimental f...The integration of machine learning with photonic and optoelectronic components is progressing rapidly, offering the potential for high-speed bio-inspired computing platforms. In this work, we employ an experimental fiber-based dendritic structure with adaptive plasticity for a learning-and-control virtual task. Specifically, we develop a closed-loop controller embedded in a single-mode fiber optical dendritic unit(ODU) that incorporates Hebbian learning principles, and we test it in a hypothetical temperature stabilization task. Our optoelectronic system operates at 1 GHz signaling and sampling rates and applies plasticity rules through the direct modulation of semiconductor optical amplifiers. Although the input correlation(ICO) learning rule we consider here is computed digitally from the experimental output of the optoelectronic system, this output is fed back into the plastic properties of the ODU physical substrate, enabling autonomous learning. In this specific configuration, we utilize only three plastic dendritic optical branches with exclusively positive weighting. We demonstrate that, despite variations in the physical system's parameters, the application of the ICO learning rule effectively mitigates temperature disturbances, ensuring robust performance. These results encourage an all-hardware solution, where optimizing feedback loop speed and embedding the ICO rule will enable continuous stabilization, finalizing a real-time platform operating at up to 1 GHz.展开更多
The paper presents the results of modern research on the effects of electromagnetic terahertz radiation in the frequency range 0.5-100 THz at different levels of power density and exposure time on the viability of nor...The paper presents the results of modern research on the effects of electromagnetic terahertz radiation in the frequency range 0.5-100 THz at different levels of power density and exposure time on the viability of normal and cancer cells. As an accompanying tool for monitoring the effect of radiation on biological cells and tissues, spectroscopic research methods in the terahertz frequency range are described, and attention is focused on the possibility of using the spectra of interstitial water as a marker of pathological processes. The problem of the safety of terahertz radiation for the human body from the point of view of its effect on the structures and systems of biological cells is also considered.展开更多
Understanding the sorption dynamics between water molecules and various solid surfaces is of great interest in diverse fundamental and industrial research.For studying such dynamics in a microsystem,existing investiga...Understanding the sorption dynamics between water molecules and various solid surfaces is of great interest in diverse fundamental and industrial research.For studying such dynamics in a microsystem,existing investigations mainly focus on sorption behaviors mediated by external temperature variations.Here,we demonstrate a route to in situ sensitive detection of laser irradiation-induced localized water molecule desorption at a sub-monolayer level on an oxide surface.Harnessing a tailored set of optical whispering-gallery-mode(WGM)resonances in a nanomembrane-based microtube cavity,the desorption can be tracked by resonance mode shift in real-time,and further explained using a combination of pseudo-firstorder and pseudo-second-order models.Additionally,upon adjusted laser excitation locations,the axial-mode-dependent responses enable the retrieval of corresponding profiles of desorption-induced perturbation at equilibrium.This study provides new insights into molecular desorption kinetics and introduces a spatially resolved sensing technique with applications in surface science,molecular sensing,and the study of desorption dynamics at the nanoscale.展开更多
For 2μm all-solid-state lasers,pulse modulation methods based on low-dimensional nanomaterial saturable absorbers(SAs)offer advantages such as compact structure,low cost,and ease of implementation.The construction of...For 2μm all-solid-state lasers,pulse modulation methods based on low-dimensional nanomaterial saturable absorbers(SAs)offer advantages such as compact structure,low cost,and ease of implementation.The construction of stable,highly nonlinear low-dimensional nanomaterial SAs is an urgent issue to be addressed.In this paper,two types of black phosphorus/rhenium disulfide(BP/ReS_(2))heterojunction with high stability were prepared separately by liquid phase exfoliation(LPE)and mechanical exfoliation(ME)methods,the nonlinear saturable absorption characteristics of the two types of heterojunctions have been characterized in detail.Then,the pulse modulation applications of these two materials have been studied in a 2μm all-solid-state thulium-doped yttrium aluminum perovskite(Tm:YAP)passively Q-switched pulsed laser.The BP/ReS_(2) heterojunction SA prepared by the LPE method demonstrates a thinner thickness and lower non-saturation optical loss,which achieved the maximum average output power 528 mW at a pump power of 6.37 W,with a narrowest pulse width of 366 ns,and a maximum peak power of 28.85 W.These results indicate that the BP/ReS_(2) heterojunction SA has great potential for optical modulation device applications.展开更多
Under the excitation of a 980 nm laser,the visible upconversion(UC)luminescence of Er^(3+)ions doped Yb^(3+)ions selfactivated NaYb(MoO_(4))_(2)phosphor and crystal,as well as the Yb^(3+)/Er^(3+)ions codoped NaBi(MoO_...Under the excitation of a 980 nm laser,the visible upconversion(UC)luminescence of Er^(3+)ions doped Yb^(3+)ions selfactivated NaYb(MoO_(4))_(2)phosphor and crystal,as well as the Yb^(3+)/Er^(3+)ions codoped NaBi(MoO_(4))_(2)crystal were investigated comprehensively.The results indicate that all three samples exhibit two significant green emission bands and a weak red emission band in the visible band corresponding to the transitions of^(2)H_(11/2)/^(4)S_(3/2)→^(4)I_(15/2)and^(4)F_(9/2)→4 I_(15/2)of Er^(3+)ions,respectively.Through the variable power density spectra of three different samples,the relationship between the energy back transfer(EBT)process of Yb^(3+)-Er^(3+)ions and the power density point and Yb^(3+)ion concentration was investigated.The EBT process was observed in both the Er^(3+)ions doped Yb^(3+)ions self-activated NaYb(MoO_(4))_(2)phosphor and crystal,as confirmed by the luminescence image of the sample.At high power density,the Yb^(3+)ions self-activated sample exhibited yellow luminescence,with the crystal appearing later than the phosphor.In contrast,the NaBi(MoO_(4))_(2)crystal displayed bright green emission within the measured power density range.In addition,by monitoring the relative intensity change of Yb^(3+)emission in 5 at%Er^(3+):NaYb(MoO_(4))_(2)crystal,the generation of EBT process in self-activated samples at high power density is more directly explained.These experimental results provide a reliable basis for our comprehensive understanding of the EBT mechanism,and also provide a reliable direction for the final determination of the optimal excitation power density for optical temperature measurement.展开更多
This study explores the application of cold plate liquid cooling technology in co-packaged optics(CPO).By integrating optical modules and the switch chip on the same substrate,CPO shortens the electrical interconnecti...This study explores the application of cold plate liquid cooling technology in co-packaged optics(CPO).By integrating optical modules and the switch chip on the same substrate,CPO shortens the electrical interconnection distance,effectively solving the problems of high power consumption and poor signal integrity of traditional pluggable optical modules under high bandwidth.However,the surge in power density and the thermal crosstalk resulting from high integration density make thermal management one of the key challenges that constrain the reliability of high-capacity co-packaged optics.For the unique architecture of CPO,this study analyzes its heat dissipation needs in detail,and a thermal management scheme is designed.The thermal management scheme is simulated and optimized based on the Navier−Stokes equation.The simulation results show that,in a 51.2 Tbit/s CPO system,the junction temperature of the switch chip is 97.3℃,the maximum junction temperature of the optical modules is 31.3℃,and the temperature difference between the optical modules is 2.4℃ to 1.2℃.To verify the simulation results,a thermal test experimental platform is built,and the experimental results show that the temperature simulation difference is within 4%and the pressure change trend is consistent with the simulation.Combining the experimental data and simulation results,the designed heat sink can satisfy the heat dissipation demands of the 51.2 Tbit/s bandwidth CPO system.This conclusion demonstrates the potential of liquid-cooling technology in CPO,providing support for research on liquid-cooling technology in the CPO.The design provides a theoretical and practical basis for the high performance and reliability of optoelectronic integration technology in wavelength division multiplexing(WDM)systems and micro-ring device applications,contributing to the application of next-generation optical communication networks.展开更多
The progressive number of old adults with cognitive impairment worldwide and the lack of efective pharmacologic therapies require the development of non-pharmacologic strategies.The photobiomodulation(PBM)is a promisi...The progressive number of old adults with cognitive impairment worldwide and the lack of efective pharmacologic therapies require the development of non-pharmacologic strategies.The photobiomodulation(PBM)is a promising method in prevention of early or mild age-related cognitive impairments.However,it remains unclear the efcacy of PBM for old patients with signifcant age-related cognitive dysfunction.In our study on male mice,we show a gradual increase in the brain amyloid beta(Aβ)levels and a decrease in brain drainage with age,which,however,is associated with a decline in cognitive function only in old(24 months of age)mice but not in middle-aged(12 months of age)and young(3 month of age)animals.These age-related features are accompanied by the development of hyperplasia of the meningeal lymphatic vessels(MLVs)in old mice underlying the decrease in brain drainage.PBM improves cognitive training exercises and Aβclearance only in young and middle-aged mice,while old animals are not sensitive to PBM.These results clearly demonstrate that the PBM efects on cognitive function are correlated with age-mediated changes in the MLV network and may be efective if the MLV function is preserved.These fndings expand fundamental knowledge about age diferences in the efectiveness of PBM for improvement of cognitive functions and Aβclearance as well as about the lymphatic mechanisms responsible for age decline in sensitivity to the therapeutic PBM efects.展开更多
Optoelectronic devices,including light sensors and light-emitting diodes,are indispensable for our daily lives.Lead-based optoelectronic materials,including colloidal quantum dots and lead-halide perovskites,have emer...Optoelectronic devices,including light sensors and light-emitting diodes,are indispensable for our daily lives.Lead-based optoelectronic materials,including colloidal quantum dots and lead-halide perovskites,have emerged as promising candidates for the next-generation optoelectronic devices.This is primarily attributed to their tailorable optoelectronic properties,industrialization-compatible manufacturing techniques,seamless integration with silicon technology and excellent device performance.In this perspective,we review recent advancements in lead-based optoelectronic devices,specifically focusing on photodetectors and active displays.By discussing the current challenges and limitations of lead-based optoelectronics,we find the exciting potential of on-chip,in-situ fabrication methods for realizing high-performance optoelectronic systems.展开更多
Three-dimensional reconstruction of tissue architecture is crucial for biomedical research.Tissue optical clearing technology overcomes light scattering limitations in biological tissues,providing an essential tool fo...Three-dimensional reconstruction of tissue architecture is crucial for biomedical research.Tissue optical clearing technology overcomes light scattering limitations in biological tissues,providing an essential tool for high-resolution three-dimensional imaging.Given the high degree of similarity between large model animals(e.g.,pigs,non-human primates)and humans in terms of anatomical structure,physiologic function,and disease mechanisms,the application of this technology in these models holds significant value for biomedical research.While well-established tissue clearing protocols exist for tissue sections,whole organs,and even entire bodies in rodents,scaling up to large animal specimens presents substantial challenges due to dimensional effects and compositional variations.This review systematically examines the methodological translation from rodent to large animals,particularly on species-specific differences in brain architecture and parenchymal organ composition that critically impact clearing efficiency.We comprehensively summarize recent applications in large animals,focusing on representative areas including neural circuit mapping,sensory organ imaging,and other related research domains,while proposing optimization strategies to overcome cross-species compatibility barriers.We hope this review will serve as a valuable reference for advancing tissue optical clearing applications in large-animal biomedical research.展开更多
Whispering-gallery-mode(WGM)microcavities have emerged as a promising alternative to traditional ultrasound probes,offering high sensitivity and wide bandwidth.In our research,we propose a novel silica WGM microprobe ...Whispering-gallery-mode(WGM)microcavities have emerged as a promising alternative to traditional ultrasound probes,offering high sensitivity and wide bandwidth.In our research,we propose a novel silica WGM microprobe device,with impressive Q factors up to 107.The side-coupled approach and special encapsulation design make the device compact,robust,and capable of utilizing in both gaseous and liquid environments.We have successfully conducted photoacoustic(PA)imaging on various samples using this device which demonstrates a high sensitivity of 5.4 mPa/√Hz and a broad bandwidth of 41 MHz at-6 dB for ultrasound.And it is capable of capturing the vibration spectrum of microparticles up to a few hundred megahertz.Our compact and lightweight device exhibits significant application potential in PA endoscopic detection,nearfield ultrasound sensing and other aspects.展开更多
The power conversion efficiency of all-perovskite tandem solar cells is predominantly constrained by optical absorption losses, especially reflection losses. In this simulation study, we propose the optimization of a ...The power conversion efficiency of all-perovskite tandem solar cells is predominantly constrained by optical absorption losses, especially reflection losses. In this simulation study, we propose the optimization of a dual-interface serrated microstructure to mitigate these optical reflection losses in all-perovskite tandem solar cells. By adjusting the geometry of the periodic serrated structures at both the front interface and the back electrode, we enhance light absorption in the widebandgap perovskite layer and promote light scattering in the narrow-bandgap perovskite layer. The structural modification reduces the reflection-induced photocurrent density loss from 4.47 to 3.65 mA cm^(-2). It is expected to boost the efficiency of all-perovskite tandem solar cells to approximately 31.13%, representing a 3.41% increase. The dual-interface optimization effectively suppresses reflection losses and improves the overall photocurrent of all-perovskite tandem solar cells. These results offer a promising strategy for minimizing optical losses and enhancing device performance in all-perovskite tandem solar cells.展开更多
As nonlinearity is highly correlated with their geometric dimensions,precise fabrication of optical micro/nanofibers(MNFs)has been a longstanding pursuit.Existing MNFs fabrication systems typically adopt horizontal st...As nonlinearity is highly correlated with their geometric dimensions,precise fabrication of optical micro/nanofibers(MNFs)has been a longstanding pursuit.Existing MNFs fabrication systems typically adopt horizontal structures,which inherently introduce inaccuracy stem from asymmetry between fiber axis/geometry and chaotic environment due to high temperature airflow,vibration,etc.,leading to deviations from the expected fiber morphology,especially for complex-structured MNFs.Here,we propose and manufacture a MNFs fabrication systems,effectively reducing fiber shape deviations during the fabrication process,enabling the fabrication of precise MNFs.To demonstrate the capability of our system in manufacturing precise structure MNFs,we design and fabricate diameter-gradient microfibers with four cascaded structures over a length of approximately 120 mm and a minimum diameter of about 1μm for on-demand nonlinearity to generate supercontinuum spectrum.Eventually,we obtain supercontinuum spectrum covering 1463-1741 nm at the−10 dB level with an efficiency of 264.62 nm∕kW,exhibiting good flatness and enabling efficient spectral broadening.展开更多
Silica nanoparticles were used to develop a bluish-green emitting Ba_(2)SiO_(4):Eu^(2+)phosphor,demonstrating their potential for white light applications.The phosphor showed a 48%enhancement of emission intensity com...Silica nanoparticles were used to develop a bluish-green emitting Ba_(2)SiO_(4):Eu^(2+)phosphor,demonstrating their potential for white light applications.The phosphor showed a 48%enhancement of emission intensity compared to conventional silicaassisted phosphors.The use of silica nanoparticles as a precursor could lead to the creation of a more homogeneous distribution of cations and dopant ions.This uniform distribution could facilitate the proper infusion of dopants into the crystal host,resulting in improved emission.The phosphor exhibited high thermal stability,with 56%of its luminescence intensity maintained even at 190℃compared to room temperature.To reduce thermal stress,a flexible remote phosphor has been developed successfully using optimized silica nanoparticles assisted Ba_(2)SiO_(4):Eu^(2+)phosphor.展开更多
In this paper, we have studied the electrical excitation of plasma-wave in N-polar AlGaN/GaN high electron mobility transistors (HEMT) under asymmetric boundaries leads to terahertz emission. Numerical calculations ar...In this paper, we have studied the electrical excitation of plasma-wave in N-polar AlGaN/GaN high electron mobility transistors (HEMT) under asymmetric boundaries leads to terahertz emission. Numerical calculations are conducted through the simultaneous solution of Maxwell’s equations and the self-consistent hydrodynamic model. By employing this method, we solved the plasma-wave model in the channel of an N-polar AlGaN/GaN HEMT. We estimate that, under ideal boundary conditions and with sufficient channel mobility, these devices could generate milliwatts of power. The effects of different GaN channel layer thickness, carrier concentration, gate length and channel carrier velocity on plasma wave oscillation and terahertz radiation in N-polar AlGaN/GaN HEMT are considered. These simulation results based on Dyakonov-Shur instability provide guidance for the future design of high-radiation-power on-chip terahertz sources based on N-polar AlGaN/ GaN HEMTs.展开更多
An ultrafast fiber laser system comprising two coherently combined amplifier channels is reported.Within this system,each channel incorporates a rod-type fiber power amplifier,with individual operations reaching appro...An ultrafast fiber laser system comprising two coherently combined amplifier channels is reported.Within this system,each channel incorporates a rod-type fiber power amplifier,with individual operations reaching approximately 233 W.The active-locking of these coherently combined channels,followed by compression using gratings,yields an output with a pulse energy of 504μJ and an average power of 403 W.Exceptional stability is maintained,with a 0.3%root mean square(RMS)deviation and a beam quality factor M^(2)<1.2.Notably,precise dispersion management of the front-end seed light effectively compensates for the accumulated high-order dispersion in subsequent amplification stages.This strategic approach results in a significant reduction in the final output pulse duration for the coherently combined laser beam,reducing it from 488 to 260 fs after the gratings compressor,while concurrently enhancing the energy of the primary peak from 65%to 92%.展开更多
In this paper,we report a coherent beam combining(CBC)system that involves two thulium-doped all-polarization maintaining(PM)fiber chirped pulse amplifiers.Through phase-locking the two channels via a fiber stretcher ...In this paper,we report a coherent beam combining(CBC)system that involves two thulium-doped all-polarization maintaining(PM)fiber chirped pulse amplifiers.Through phase-locking the two channels via a fiber stretcher by using the stochastic parallel gradient descent(SPGD)algorithm,a maximum average power of 265 W is obtained,with a CBC efficiency of 81%and a residual phase error of λ/17.After de-chirping by a pair of diffraction gratings,the duration of the combined laser pulse is compressed to 690 fs.Taking into account the compression efficiency of 90%and the main peak energy proportion of 91%,the corresponding peak power is calculated to be 4 MW.The laser noise characteristics before and after CBC are examined,and the results indicate that the CBC would degrade the low frequency relative intensity noise(RIN),of which the integration is 1.74%in[100 Hz,2 MHz]at the maximum combined output power.In addition,the effects of the nonlinear spectrum broadening during chirped pulse amplification on the CBC efficiency are also investigated,showing that a higher extent of pulse stretching is effective in alleviating the spectrum broadening and realizing a higher output power with decent combining efficiency.展开更多
基金This work was supported by the Foundation of State Key Laboratory of High-Power Semiconductor Laser,Changchun University of Science and Technology,the National Natural Science Foundation of China(Grant No.61975182)Key project of Natural Science foundation of Zhejiang Province(No.LZ23F050001).
文摘Bound states in the continuum (BICs) offer a promising solution to achieving high-quality factor (Q factor) cavities. However, finite-size effects severely deteriorate the BIC mode in practical applications. This paper reports the experimental demonstration of an electrically pumped 940 nm laser based on optimized BIC cavity, achieving a high Q factor of up to 1.18 × 10^(4) even with finite photonic crystal footprint, which is two orders of magnitude larger than un-optimized BIC design. Two strategies have been systematically investigated to mitigate finite-size effects: reflective photonic crystal cavity design and graded photonic crystal cavity design. Both methods significantly improve the Q factor, demonstrating the effectiveness of preserving BIC characteristics in finite-sized photonic crystal cavities. In addition, the reflective boundary photonic crystal design is fabricated and experimentally characterized to demonstrate its lasing characteristics. The fabricated laser exhibits single-mode operation with a signal-to-noise ratio of 38.6 dB. These results pave the way for future designs of BICs with finite size in real applications, promoting the performance of BIC-based integrated lasers.
基金supported by the National Key Research and Development Program of China(No.2019YFB2203100).
文摘Taking the advantage of ultrafast optical linear and nonlinear effects, all-optical signal processing(AOSP) enables manipulation, regeneration, and computing of information directly in optical domain without resorting to electronics. As a promising photonic integration platform, silicon-on-insulator(SOI) has the advantage of complementary metal oxide semiconductor(CMOS) compatibility, low-loss, compact size as well as large optical nonlinearities. In this paper, we review the recent progress in the project granted to develop silicon-based reconfigurable AOSP chips, which aims to combine the merits of AOSP and silicon photonics to solve the unsustainable cost and energy challenges in future communication and big data applications. Three key challenges are identified in this project:(1) how to finely manipulate and reconfigure optical fields,(2) how to achieve ultra-low loss integrated silicon waveguides and significant enhancement of nonlinear effects,(3) how to mitigate crosstalk between optical, electrical and thermal components. By focusing on these key issues, the following major achievements are realized during the project. First, ultra-low loss silicon-based waveguides as well as ultra-high quality microresonators are developed by advancing key fabrication technologies as well as device structures. Integrated photonic filters with bandwidth and free spectral range reconfigurable in a wide range were realized to finely manipulate and select input light fields with a high degree of freedom. Second, several mechanisms and new designs that aim at nonlinear enhancement have been proposed, including optical ridge waveguides with reverse biased PIN junction, slot waveguides,multimode waveguides and parity-time symmetry coupled microresonators. Advanced AOSP operations are verified with these novel designs. Logical computations at 100 Gbit/s were demonstrated with self-developed, monolithic integrated programmable optical logic array. High-dimensional multi-value logic operations based on the four-wave mixing effect are realized. Multi-channel all-optical amplitude and phase regeneration technology is developed, and a multi-channel, multiformat, reconfigurable all-optical regeneration chip is realized. Expanding regeneration capacity via spatial dimension is also verified. Third, the crosstalk from optical as well as thermal coupling due to high-density integration are mitigated by developing novel optical designs and advanced packaging technologies, enabling high-density, small size, multi-channel and multi-functional operation with low power consumption. Finally, four programmable AOSP chips are developed, i.e.,programmable photonic filter chip, programmable photonic logic operation chip, multi-dimensional all-optical regeneration chip, and multi-channel and multi-functional AOSP chip with packaging. The major achievements developed in this project pave the way toward ultra-low loss, high-speed, high-efficient, high-density information processing in future classical and non-classical communication and computing applications.
基金The work was financially supported by a grant from the Russian Science Foundation No.22-65-00096.
文摘Current study presents an advanced method for improving the visualization of subsurface blood vessels using laser speckle contrast imaging (LSCI), enhanced through principal component analysis (PCA) filtering. By combining LSCI and laser speckle entropy imaging with PCA filtering, the method effectively separates static and dynamic components of the speckle signal, significantly improving the accuracy of blood flow assessments, even in the presence of static scattering layers located above and below the vessel. Experiments conducted on optical phantoms, with the vessel depths ranging from 0.6 to 2 mm, and in vivo studies on a laboratory mouse ear demonstrate substantial improvements in image contrast and resolution. The method’s sensitivity to blood flow velocity within the physiologic range (0.98-19.66 mm/s) is significantly enhanced, while its sensitivity to vessel depth is minimized. These results highlight the method’s ability to assess blood flow velocity independently of vessel depth, overcoming a major limitation of conventional LSCI techniques. The proposed approach holds great potential for non-invasive biomedical imaging, offering improved diagnostic accuracy and contrast in vascular imaging. These findings may be particularly valuable for advancing the use of LSCI in clinical diagnostics and biomedical research, where high precision in blood flow monitoring is essential.
基金supported by the National Key Research and Development Program of China(No.2022YFA1204800)the National Natural Science Foundation of China(Grant No.U2001219)+1 种基金Hubei Provincial Natural Science Foundation of China(No.2023AFA034)the Key R&D program of Hubei Province(No.2023BAB102).
文摘Metal halide perovskites have become one of the most competitive new-generation optoelectronic materials due to their excellent optoelectronic properties. Vacuum evaporation can produce high-purity and large-area films, leading to the wide application of this method in the semiconductor industry and optoelectronics field. However, the electroluminescent performance of vacuum-evaporated perovskite light-emitting diodes(PeLEDs) still lags behind those counterparts fabricated by solution methods. Herein, based on vacuum evaporation, 3D perovskite films are obtained by three-source co-evaporation.Considering the unique quantum well structure of quasi-2D perovskite can significantly enhance the exciton binding energy and improve the radiative recombination rate, leading to a high photoluminescence quantum yield(PLQY). Subsequently,the highly stable and low-defect-density quasi-2D perovskite is introduced into 3D perovskite films through post-treatment with phenethylammonium chloride(PEACl). To minimize the degradation of film quality caused by PEACl treatment, a layer of guanidinium bromide(GABr) is vacuum evaporated on top of PEACl treatment to further improve the quality of emitting layer. Finally, under the synergistic post-processing modification of PEACl and GABr, blue PeLEDs with a maximum external quantum efficiency(EQE) of 6.09% and a maximum brightness of 1325 cd/m^(2) are successfully obtained. This work deepens the understanding of 2D/3D heterojunctions and provides a new approach to construct PeLEDs with high performance.
基金supported by the European Union’s Horizon 2020 Research and Innovation Programme under Grant 899265(ADOPD)the Program for Centres and Units of Excellence in R&D María de Maeztu under Project CEX2021-001164-M funded by MCIN/AEI/10.13039/501100011033,and the project INFOLANET PID2022-139409NB-I00 funded by MCIN/AEI/10.13039/501100011033.
文摘The integration of machine learning with photonic and optoelectronic components is progressing rapidly, offering the potential for high-speed bio-inspired computing platforms. In this work, we employ an experimental fiber-based dendritic structure with adaptive plasticity for a learning-and-control virtual task. Specifically, we develop a closed-loop controller embedded in a single-mode fiber optical dendritic unit(ODU) that incorporates Hebbian learning principles, and we test it in a hypothetical temperature stabilization task. Our optoelectronic system operates at 1 GHz signaling and sampling rates and applies plasticity rules through the direct modulation of semiconductor optical amplifiers. Although the input correlation(ICO) learning rule we consider here is computed digitally from the experimental output of the optoelectronic system, this output is fed back into the plastic properties of the ODU physical substrate, enabling autonomous learning. In this specific configuration, we utilize only three plastic dendritic optical branches with exclusively positive weighting. We demonstrate that, despite variations in the physical system's parameters, the application of the ICO learning rule effectively mitigates temperature disturbances, ensuring robust performance. These results encourage an all-hardware solution, where optimizing feedback loop speed and embedding the ICO rule will enable continuous stabilization, finalizing a real-time platform operating at up to 1 GHz.
基金This work was supported by the Russian Science Foundation Grant 23-14-00287.
文摘The paper presents the results of modern research on the effects of electromagnetic terahertz radiation in the frequency range 0.5-100 THz at different levels of power density and exposure time on the viability of normal and cancer cells. As an accompanying tool for monitoring the effect of radiation on biological cells and tissues, spectroscopic research methods in the terahertz frequency range are described, and attention is focused on the possibility of using the spectra of interstitial water as a marker of pathological processes. The problem of the safety of terahertz radiation for the human body from the point of view of its effect on the structures and systems of biological cells is also considered.
基金the support from the National Key R&D Program of China under Grant 2023YFE0208700the National Natural Science Foundation of China under Grants 62422503,12474375,12274182,and 62305093+2 种基金Science and Technology Innovation Commission of Shenzhen under Grants JCYJ20220531095604009,JCYJ20240813104819027,RCYX20221008092907027,and GXWD20231129101105001Hainan Province"Nanhai New Star"Science and Technology Innovation Talent Platform Program under Grant NHXXRCXM202304the Innovation/Entrepreneurship Program of Jiangsu Province under Grants JSSCTD202146 and JSSCRC2021538.
文摘Understanding the sorption dynamics between water molecules and various solid surfaces is of great interest in diverse fundamental and industrial research.For studying such dynamics in a microsystem,existing investigations mainly focus on sorption behaviors mediated by external temperature variations.Here,we demonstrate a route to in situ sensitive detection of laser irradiation-induced localized water molecule desorption at a sub-monolayer level on an oxide surface.Harnessing a tailored set of optical whispering-gallery-mode(WGM)resonances in a nanomembrane-based microtube cavity,the desorption can be tracked by resonance mode shift in real-time,and further explained using a combination of pseudo-firstorder and pseudo-second-order models.Additionally,upon adjusted laser excitation locations,the axial-mode-dependent responses enable the retrieval of corresponding profiles of desorption-induced perturbation at equilibrium.This study provides new insights into molecular desorption kinetics and introduces a spatially resolved sensing technique with applications in surface science,molecular sensing,and the study of desorption dynamics at the nanoscale.
基金supported by the Shandong Provincial Key R&D Program(No.2024CXGC010106)Joint Fund for Innovation and Development of the Natural Science Foundation of Shandong Province(No.ZR2023LLZ011)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2022MA084)the Natural Science Foundation of Shandong Province for Youths(No.ZR2022QF081).
文摘For 2μm all-solid-state lasers,pulse modulation methods based on low-dimensional nanomaterial saturable absorbers(SAs)offer advantages such as compact structure,low cost,and ease of implementation.The construction of stable,highly nonlinear low-dimensional nanomaterial SAs is an urgent issue to be addressed.In this paper,two types of black phosphorus/rhenium disulfide(BP/ReS_(2))heterojunction with high stability were prepared separately by liquid phase exfoliation(LPE)and mechanical exfoliation(ME)methods,the nonlinear saturable absorption characteristics of the two types of heterojunctions have been characterized in detail.Then,the pulse modulation applications of these two materials have been studied in a 2μm all-solid-state thulium-doped yttrium aluminum perovskite(Tm:YAP)passively Q-switched pulsed laser.The BP/ReS_(2) heterojunction SA prepared by the LPE method demonstrates a thinner thickness and lower non-saturation optical loss,which achieved the maximum average output power 528 mW at a pump power of 6.37 W,with a narrowest pulse width of 366 ns,and a maximum peak power of 28.85 W.These results indicate that the BP/ReS_(2) heterojunction SA has great potential for optical modulation device applications.
基金Foundation of China(Grant No.52202001)Special Project of the National Natural Science Foundation of China(Grant No.62241501)+1 种基金Major Science and Technology of Anhui Province(No.202203a05020002)University Natural Science Research Project of Anhui Province(No.KJ2021 A0388)supported this study.
文摘Under the excitation of a 980 nm laser,the visible upconversion(UC)luminescence of Er^(3+)ions doped Yb^(3+)ions selfactivated NaYb(MoO_(4))_(2)phosphor and crystal,as well as the Yb^(3+)/Er^(3+)ions codoped NaBi(MoO_(4))_(2)crystal were investigated comprehensively.The results indicate that all three samples exhibit two significant green emission bands and a weak red emission band in the visible band corresponding to the transitions of^(2)H_(11/2)/^(4)S_(3/2)→^(4)I_(15/2)and^(4)F_(9/2)→4 I_(15/2)of Er^(3+)ions,respectively.Through the variable power density spectra of three different samples,the relationship between the energy back transfer(EBT)process of Yb^(3+)-Er^(3+)ions and the power density point and Yb^(3+)ion concentration was investigated.The EBT process was observed in both the Er^(3+)ions doped Yb^(3+)ions self-activated NaYb(MoO_(4))_(2)phosphor and crystal,as confirmed by the luminescence image of the sample.At high power density,the Yb^(3+)ions self-activated sample exhibited yellow luminescence,with the crystal appearing later than the phosphor.In contrast,the NaBi(MoO_(4))_(2)crystal displayed bright green emission within the measured power density range.In addition,by monitoring the relative intensity change of Yb^(3+)emission in 5 at%Er^(3+):NaYb(MoO_(4))_(2)crystal,the generation of EBT process in self-activated samples at high power density is more directly explained.These experimental results provide a reliable basis for our comprehensive understanding of the EBT mechanism,and also provide a reliable direction for the final determination of the optimal excitation power density for optical temperature measurement.
基金support from the Beijing Municipal Science and Technology Project(No.Z241100004224020)the National Natural Science Foundation of China(Grant No.62204258)the Key Research and Development Program of Jiangsu(No.BE2022051-3).
文摘This study explores the application of cold plate liquid cooling technology in co-packaged optics(CPO).By integrating optical modules and the switch chip on the same substrate,CPO shortens the electrical interconnection distance,effectively solving the problems of high power consumption and poor signal integrity of traditional pluggable optical modules under high bandwidth.However,the surge in power density and the thermal crosstalk resulting from high integration density make thermal management one of the key challenges that constrain the reliability of high-capacity co-packaged optics.For the unique architecture of CPO,this study analyzes its heat dissipation needs in detail,and a thermal management scheme is designed.The thermal management scheme is simulated and optimized based on the Navier−Stokes equation.The simulation results show that,in a 51.2 Tbit/s CPO system,the junction temperature of the switch chip is 97.3℃,the maximum junction temperature of the optical modules is 31.3℃,and the temperature difference between the optical modules is 2.4℃ to 1.2℃.To verify the simulation results,a thermal test experimental platform is built,and the experimental results show that the temperature simulation difference is within 4%and the pressure change trend is consistent with the simulation.Combining the experimental data and simulation results,the designed heat sink can satisfy the heat dissipation demands of the 51.2 Tbit/s bandwidth CPO system.This conclusion demonstrates the potential of liquid-cooling technology in CPO,providing support for research on liquid-cooling technology in the CPO.The design provides a theoretical and practical basis for the high performance and reliability of optoelectronic integration technology in wavelength division multiplexing(WDM)systems and micro-ring device applications,contributing to the application of next-generation optical communication networks.
基金support with the enzyme immunoassay and immunofuorescence analysis within Project No.GR 1022040700963-8(IBPPM RAS).
文摘The progressive number of old adults with cognitive impairment worldwide and the lack of efective pharmacologic therapies require the development of non-pharmacologic strategies.The photobiomodulation(PBM)is a promising method in prevention of early or mild age-related cognitive impairments.However,it remains unclear the efcacy of PBM for old patients with signifcant age-related cognitive dysfunction.In our study on male mice,we show a gradual increase in the brain amyloid beta(Aβ)levels and a decrease in brain drainage with age,which,however,is associated with a decline in cognitive function only in old(24 months of age)mice but not in middle-aged(12 months of age)and young(3 month of age)animals.These age-related features are accompanied by the development of hyperplasia of the meningeal lymphatic vessels(MLVs)in old mice underlying the decrease in brain drainage.PBM improves cognitive training exercises and Aβclearance only in young and middle-aged mice,while old animals are not sensitive to PBM.These results clearly demonstrate that the PBM efects on cognitive function are correlated with age-mediated changes in the MLV network and may be efective if the MLV function is preserved.These fndings expand fundamental knowledge about age diferences in the efectiveness of PBM for improvement of cognitive functions and Aβclearance as well as about the lymphatic mechanisms responsible for age decline in sensitivity to the therapeutic PBM efects.
基金supported by the National Key Research and Development Program of China(Nos.2024YFA1209503 and 2021YFB3501800)the National Natural Science Foundation of China(Grant Nos.62322505 and 62374069)the Innovation Project of Optics Valley Laboratory(No.OVL2023ZD002).
文摘Optoelectronic devices,including light sensors and light-emitting diodes,are indispensable for our daily lives.Lead-based optoelectronic materials,including colloidal quantum dots and lead-halide perovskites,have emerged as promising candidates for the next-generation optoelectronic devices.This is primarily attributed to their tailorable optoelectronic properties,industrialization-compatible manufacturing techniques,seamless integration with silicon technology and excellent device performance.In this perspective,we review recent advancements in lead-based optoelectronic devices,specifically focusing on photodetectors and active displays.By discussing the current challenges and limitations of lead-based optoelectronics,we find the exciting potential of on-chip,in-situ fabrication methods for realizing high-performance optoelectronic systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.62375096,82361138569,82372012,82402341)the Open Competition Project of Wuhan East Lake High-tech Development Zone(Grant No.2023KJB224)the Innovation Project of Optics Valley Laboratory(Grant No.OVL2025BB008).
文摘Three-dimensional reconstruction of tissue architecture is crucial for biomedical research.Tissue optical clearing technology overcomes light scattering limitations in biological tissues,providing an essential tool for high-resolution three-dimensional imaging.Given the high degree of similarity between large model animals(e.g.,pigs,non-human primates)and humans in terms of anatomical structure,physiologic function,and disease mechanisms,the application of this technology in these models holds significant value for biomedical research.While well-established tissue clearing protocols exist for tissue sections,whole organs,and even entire bodies in rodents,scaling up to large animal specimens presents substantial challenges due to dimensional effects and compositional variations.This review systematically examines the methodological translation from rodent to large animals,particularly on species-specific differences in brain architecture and parenchymal organ composition that critically impact clearing efficiency.We comprehensively summarize recent applications in large animals,focusing on representative areas including neural circuit mapping,sensory organ imaging,and other related research domains,while proposing optimization strategies to overcome cross-species compatibility barriers.We hope this review will serve as a valuable reference for advancing tissue optical clearing applications in large-animal biomedical research.
基金supported by the National Natural Science Foundation of China(Grant No.62305006)Natural Science Foundation of Jiangsu Province(Grant Nos.BK20230287,BK20230286)Nantong Social Livelihood Science and Technology Planning Project(Grant Nos.MS12022003,MS2023071).
文摘Whispering-gallery-mode(WGM)microcavities have emerged as a promising alternative to traditional ultrasound probes,offering high sensitivity and wide bandwidth.In our research,we propose a novel silica WGM microprobe device,with impressive Q factors up to 107.The side-coupled approach and special encapsulation design make the device compact,robust,and capable of utilizing in both gaseous and liquid environments.We have successfully conducted photoacoustic(PA)imaging on various samples using this device which demonstrates a high sensitivity of 5.4 mPa/√Hz and a broad bandwidth of 41 MHz at-6 dB for ultrasound.And it is capable of capturing the vibration spectrum of microparticles up to a few hundred megahertz.Our compact and lightweight device exhibits significant application potential in PA endoscopic detection,nearfield ultrasound sensing and other aspects.
基金supported by National Key R&D Program of China (2023YFB3608900)the Innovation Project of Optics Valley Laboratory (OVL2024ZD002)+6 种基金the University of New South Wales-Huazhong University of Science and Technology Strategic Partnership Research Seed Fundthe State Key Laboratory of Photoelectric Conversion and Utilization of Solar Energy (Innovation Fund Project SKLPCU24OP007)Wuhan Science and Technology Innovation Bureau (2024010702020023)Guangdong Provincial Key Laboratory of Manufacturing Equipment Digitization (2023B1212060012)Hubei Optical Fundamental Research Centerthe National Natural Science Foundation of China (62174064)the Analytical and Testing Center of Huazhong University of Science and Technology for their support
文摘The power conversion efficiency of all-perovskite tandem solar cells is predominantly constrained by optical absorption losses, especially reflection losses. In this simulation study, we propose the optimization of a dual-interface serrated microstructure to mitigate these optical reflection losses in all-perovskite tandem solar cells. By adjusting the geometry of the periodic serrated structures at both the front interface and the back electrode, we enhance light absorption in the widebandgap perovskite layer and promote light scattering in the narrow-bandgap perovskite layer. The structural modification reduces the reflection-induced photocurrent density loss from 4.47 to 3.65 mA cm^(-2). It is expected to boost the efficiency of all-perovskite tandem solar cells to approximately 31.13%, representing a 3.41% increase. The dual-interface optimization effectively suppresses reflection losses and improves the overall photocurrent of all-perovskite tandem solar cells. These results offer a promising strategy for minimizing optical losses and enhancing device performance in all-perovskite tandem solar cells.
基金supported by the Natural Science Foundation of Zhejiang Province China grant[LR22F050006(YM)]the National Natural Science Foundation of China(NSFC)grant[62222511(YM)]+1 种基金the National Key Research and Development Program of China grant[2023YFF0613000(YM)]the STI 2030-Major Projects grant[2021ZD0200401(YM)].
文摘As nonlinearity is highly correlated with their geometric dimensions,precise fabrication of optical micro/nanofibers(MNFs)has been a longstanding pursuit.Existing MNFs fabrication systems typically adopt horizontal structures,which inherently introduce inaccuracy stem from asymmetry between fiber axis/geometry and chaotic environment due to high temperature airflow,vibration,etc.,leading to deviations from the expected fiber morphology,especially for complex-structured MNFs.Here,we propose and manufacture a MNFs fabrication systems,effectively reducing fiber shape deviations during the fabrication process,enabling the fabrication of precise MNFs.To demonstrate the capability of our system in manufacturing precise structure MNFs,we design and fabricate diameter-gradient microfibers with four cascaded structures over a length of approximately 120 mm and a minimum diameter of about 1μm for on-demand nonlinearity to generate supercontinuum spectrum.Eventually,we obtain supercontinuum spectrum covering 1463-1741 nm at the−10 dB level with an efficiency of 264.62 nm∕kW,exhibiting good flatness and enabling efficient spectral broadening.
基金Science and Engineering Research Board (SERB)Department of Science and Technology, Government of India (EMR-2016-005574)+1 种基金Council of Scientific&Industrial Research, Government of India (09/1095(0053)/2020-EMR-I) for financial supportSASTRA Deemed to be University,Thanjavur for providing SASTRA-T.R. Rajagopalan (SASTRA-TRR) fund and the infrastructural support
文摘Silica nanoparticles were used to develop a bluish-green emitting Ba_(2)SiO_(4):Eu^(2+)phosphor,demonstrating their potential for white light applications.The phosphor showed a 48%enhancement of emission intensity compared to conventional silicaassisted phosphors.The use of silica nanoparticles as a precursor could lead to the creation of a more homogeneous distribution of cations and dopant ions.This uniform distribution could facilitate the proper infusion of dopants into the crystal host,resulting in improved emission.The phosphor exhibited high thermal stability,with 56%of its luminescence intensity maintained even at 190℃compared to room temperature.To reduce thermal stress,a flexible remote phosphor has been developed successfully using optimized silica nanoparticles assisted Ba_(2)SiO_(4):Eu^(2+)phosphor.
基金supported by the National Natural Science Foundation of China(Grant Nos.92163204,61921002,and 62171098)Students’Innovation and Entrepreneurship Foundation of USTC(Nos.CY2024C004B and CY2024X006A)。
文摘In this paper, we have studied the electrical excitation of plasma-wave in N-polar AlGaN/GaN high electron mobility transistors (HEMT) under asymmetric boundaries leads to terahertz emission. Numerical calculations are conducted through the simultaneous solution of Maxwell’s equations and the self-consistent hydrodynamic model. By employing this method, we solved the plasma-wave model in the channel of an N-polar AlGaN/GaN HEMT. We estimate that, under ideal boundary conditions and with sufficient channel mobility, these devices could generate milliwatts of power. The effects of different GaN channel layer thickness, carrier concentration, gate length and channel carrier velocity on plasma wave oscillation and terahertz radiation in N-polar AlGaN/GaN HEMT are considered. These simulation results based on Dyakonov-Shur instability provide guidance for the future design of high-radiation-power on-chip terahertz sources based on N-polar AlGaN/ GaN HEMTs.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.9215010612021004,and 11934006)the Innovation Project of Optics Valley Laboratory(No.OVL2021ZD001),the Major Program(JD)of Hubei Province(No.203BAA015)the Cross Research Support Program of Huazhong University of Science and Technology(No.2023JCYJ041).
文摘An ultrafast fiber laser system comprising two coherently combined amplifier channels is reported.Within this system,each channel incorporates a rod-type fiber power amplifier,with individual operations reaching approximately 233 W.The active-locking of these coherently combined channels,followed by compression using gratings,yields an output with a pulse energy of 504μJ and an average power of 403 W.Exceptional stability is maintained,with a 0.3%root mean square(RMS)deviation and a beam quality factor M^(2)<1.2.Notably,precise dispersion management of the front-end seed light effectively compensates for the accumulated high-order dispersion in subsequent amplification stages.This strategic approach results in a significant reduction in the final output pulse duration for the coherently combined laser beam,reducing it from 488 to 260 fs after the gratings compressor,while concurrently enhancing the energy of the primary peak from 65%to 92%.
基金supported in part by the National Key Research and Development Program of China(No.2022YFB3606000)in part by State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020ZR02).
文摘In this paper,we report a coherent beam combining(CBC)system that involves two thulium-doped all-polarization maintaining(PM)fiber chirped pulse amplifiers.Through phase-locking the two channels via a fiber stretcher by using the stochastic parallel gradient descent(SPGD)algorithm,a maximum average power of 265 W is obtained,with a CBC efficiency of 81%and a residual phase error of λ/17.After de-chirping by a pair of diffraction gratings,the duration of the combined laser pulse is compressed to 690 fs.Taking into account the compression efficiency of 90%and the main peak energy proportion of 91%,the corresponding peak power is calculated to be 4 MW.The laser noise characteristics before and after CBC are examined,and the results indicate that the CBC would degrade the low frequency relative intensity noise(RIN),of which the integration is 1.74%in[100 Hz,2 MHz]at the maximum combined output power.In addition,the effects of the nonlinear spectrum broadening during chirped pulse amplification on the CBC efficiency are also investigated,showing that a higher extent of pulse stretching is effective in alleviating the spectrum broadening and realizing a higher output power with decent combining efficiency.
