Vortex beams have attracted great attention due to their promising applications in the fields of high-capacity optical communication,optical micromanipulation,and quantum information processing.Here,we demonstrate vor...Vortex beams have attracted great attention due to their promising applications in the fields of high-capacity optical communication,optical micromanipulation,and quantum information processing.Here,we demonstrate vortex beams with flexible control of the topological charge and modes in a carbon dots random laser for the first time.Vortex beams with different types,including the Laguerre-Gaussian(LG),Bessel-Gaussian(BG),LG-superposition,and polarized vortex beams with topological charges up to 50,have been successfully achieved.Moreover,vortex beams can be well realized in carbon dots random lasers with different emission wavelengths covering from 465 to 612 nm.This work would not only enrich the types of vortex laser,especially for solution-processable lasers,but also provide a new route to realizing multicolor and wavelength-tunable vortex lasers.展开更多
This paper proposes a continuously tunable random lasers(RLs)based on the gain system of cellulose nanocrystals(CNCs)-doped hydrogels and the laser dye made of Rhodamine B(Rh B).Between them,the prepared CNCs-doped hy...This paper proposes a continuously tunable random lasers(RLs)based on the gain system of cellulose nanocrystals(CNCs)-doped hydrogels and the laser dye made of Rhodamine B(Rh B).Between them,the prepared CNCs-doped hydrogels have not only a weak scattering structure that can provide excellent multiple scattering,thus yielding a large gain,but also good mechanical properties that can provide great advantages in the tuning of RL.The experimental results indicate that the RL emission wavelength blue shifts with an increase in the stretching length.The continuous tuning range reaches up to 7.1 nm when the CNCs-doped hydrogels are stretched to 400%.In addition,the proposed CNCs-doped hydrogels effectively solve the problem of the structures of traditional hydrogels,which are easily destroyed during repeated stretching and ensure good stability of RL output and tuning.The RL error is tested and found to be less than 0.5 nm,when the same length is stretched during repeated stretching.Our results provide a new approach to obtain tunable and stable RLs.Simultaneously,in combination with the good biocompatibility of CNCs-doped hydrogels,the proposed RLs demonstrated great importance in the biological field.展开更多
In this Letter,we designed a random laser based on a nematic liquid crystal with titanium nitride nanoparticles,which has low spatial coherence,and its spatial coherence can be dynamically manipulated by the applied v...In this Letter,we designed a random laser based on a nematic liquid crystal with titanium nitride nanoparticles,which has low spatial coherence,and its spatial coherence can be dynamically manipulated by the applied voltage.In a scattering environment,the speckle effect can be effectively suppressed using the random laser as the light source,and the speckle degree is controlled by the applied voltage.Moreover,with the decrease of the spatial coherence of the random laser,the imaging edges become blurred.We provided a quantitative way to optimize the image quality between uniformity and edge sharpness while improving the signal-to-noise ratio.展开更多
Random lasers are a type of lasers that lack typical resonator structures,offering benefits such as easy integration,low cost,and low spatial coherence.These features make them popular for speckle-free imaging and ran...Random lasers are a type of lasers that lack typical resonator structures,offering benefits such as easy integration,low cost,and low spatial coherence.These features make them popular for speckle-free imaging and random number generation.However,due to their high threshold and phase instability,the production of picosecond random lasers has still been a challenge.In this work,we have developed three dyes incorporating polymer optical fibers doped with various scattering nanoparticles to produce short-pulsed random fiber lasers.Notably,stable picosecond random laser emission lasting600 ps is observed at a low pump energy of 50μJ,indicating the gain-switching mechanism.Population inversion and gain undergo an abrupt surge as the intensity of the continuously pumped light nears the threshold level.When the intensity of the continuously pumped light reaches a specific value,the number of inversion populations in the“scattering cavity”surpasses the threshold rapidly.Simulation results based on a model that considers power-dependent gain saturation confirmed the above phenomenon.This research helps expand the understanding of the dynamics behind random medium-stimulated emission in random lasers and opens up possibilities for mode locking in these systems.展开更多
We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and ...We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and non-pump areas. The dependence of lasing modes on the pump area is qualitatively explained by means of the model in which the lasing is ascribed to the interaction of the complex localized modes in the active random medium with local aperiodic quasi-structure with appropriate pump light. There exist different pump sizes for lasing with different modes. As the pump size decreases in this random system, the pump threshold of the lasing modes increases. There are different lasing modes in different excitation regions in this random system. This gives us some information about the dependence of lasing modes on pump areas in active random media.展开更多
Terahertz （THz） random lazing is studied numerically for two-dimensional disordered media made of ruby grains with a three-level atomic system. A method via the adjustment of the pumping area to control the polariza...Terahertz （THz） random lazing is studied numerically for two-dimensional disordered media made of ruby grains with a three-level atomic system. A method via the adjustment of the pumping area to control the polarization of the THz wave is proposed. Computed results reveal that transverse electric THz lasing modes could occur if pumping is supplied on the whole medium, while transverse magnetic THz lasing modes could occur if pumping is appropriately supplied on a partial area of the medium.展开更多
Flexible electrically pumped random laser（RL） based on ZnO nanowires is demonstrated for the first time to our knowledge. The ZnO nanowires each with a length of 5 μm and an average diameter of 180 nm are synthesiz...Flexible electrically pumped random laser（RL） based on ZnO nanowires is demonstrated for the first time to our knowledge. The ZnO nanowires each with a length of 5 μm and an average diameter of 180 nm are synthesized on flexible substrate（ITO/PET） by a simple hydrothermal method. No obvious visible defect-related-emission band is observed in the photoluminescence（PL） spectrum, indicating that the ZnO nanowires grown on the flexible ITO/PET substrate have few defects. In order to achieve electrically pumped random lasing with a lower threshold, the metal–insulator–semiconductor（MIS） structure of Au/SiO2/ZnO on ITO/PET substrate is fabricated by low temperature process. With sufficient forward bias, the as-fabricated flexible device exhibits random lasing, and a low threshold current of ～ 11.5 m A and high luminous intensity are obtained from the ZnO-based random laser. It is believed that this work offers a case study for developing the flexible electrically pumped random lasing from ZnO nanowires.展开更多
Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral ol...Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide(DPP) which possesses POSS as scatteres experimentally performs strong NFSE, which confirms the physical simulation results. Moreover, coherent random laser is triggered from the DPP aggregates in carbon disulfide. It is the NFSE of POSS NPs connected to both ends of DPP through covalent bonds and the NFSE of their aggregation thanks to DPP’s aggregation that is responsible for the coherent random laser. So, this work develops a method to improve weak scattering of system through construction of molecules, and opens a road to a variety of novel interdisciplinary investigations, involving molecular designing for disordered photonics.展开更多
Here,a plasmon-enhanced random laser was achieved by incorporating gold nanostars（NS） into disordered polymer and Cd Se/Zn S quantum dots（QDs） gain medium films,in which the surface plasmon resonance of gold NS ca...Here,a plasmon-enhanced random laser was achieved by incorporating gold nanostars（NS） into disordered polymer and Cd Se/Zn S quantum dots（QDs） gain medium films,in which the surface plasmon resonance of gold NS can greatly enhance the scattering cross section and bring a large gain volume.The random distribution of gold NS in the gain medium film formed a laser-mode resonator.Under a single-pulse pumping,the scattering center of gold NS-based random laser exhibits enhanced performance of a lasing threshold of 0.8 m J/cm^2 and a full width as narrow as 6 nm at half maximum.By utilizing the local enhancement characteristic of the electric field at the sharp apexes of the gold NS,the emission intensity of the random laser was increased.In addition,the gold NS showed higher thermal stability than the silver nanoparticles,withstanding high temperature heating up to 200？C.The results of metal nanostructures with enriched hot spots and excellent temperature stability have tremendous potential applications in the fields of biological identification,medical diagnostics,lighting,and display devices.展开更多
Optical memory effect-based speckle-correlated technology has been developed for reconstructing hidden objectsfrom disordered speckle patterns,achieving imaging through scattering layers.However,the lighting efficienc...Optical memory effect-based speckle-correlated technology has been developed for reconstructing hidden objectsfrom disordered speckle patterns,achieving imaging through scattering layers.However,the lighting efficiency and fieldof view of existing speckle-correlated imaging systems are limited.Here,a near-infrared low spatial coherence fiberrandom laser illumination method is proposed to address the above limitations.Through the utilization of random Rayleighscattering within dispersion-shifted fibers to provide feedback,coupled with stimulated Raman scattering for amplification,a near-infrared fiber random laser exhibiting a high spectral density and extremely low spatial coherence is generated.Based on the designed fiber random laser,speckle-correlated imaging through scattering layers is achieved,with highlighting efficiency and a large imaging field of view.This work improves the performance of speckle-correlated imagingand enriches the research on imaging through scattering medium.展开更多
The optical rogue wave(RW),known as a short-lived extraordinarily high amplitude dynamics phenomenon with small appearing probabilities,plays an important role in revealing and understanding the fundamental physics of...The optical rogue wave(RW),known as a short-lived extraordinarily high amplitude dynamics phenomenon with small appearing probabilities,plays an important role in revealing and understanding the fundamental physics of nonlinear wave propagations in optical systems.The random fiber laser(RFL),featured with cavity-free and“modeless”structure,has opened up new avenues for fundamental physics research and potential practical applications combining nonlinear optics and laser physics.Here,the extreme event of optical RW induced by noise-driven modulation instability that interacts with the cascaded stimulated Brillouin scattering,the quasi-phase-matched four-wave mixing as well as the random mode resonance process is observed in a Brillouin random fiber laser comb(BRFLC).Temporal and statistical characteristics of the RWs concerning their emergence and evolution are experimentally explored and analyzed.Specifically,temporally localized structures with high intensities including chair-like pulses with a sharp leading edge followed by a trailing plateau appear frequently in the BRFLC output,which can evolve to chair-like RW pulses with adjustable pulse duration and amplitude under controlled conditions.This investigation provides a deep insight into the extreme event of RWs and paves the way for RW manipulation for its generation and elimination in RFLs through adapted laser configuration.展开更多
We present a Brillouin–Raman random fiber laser(BRRFL)with full-open linear cavity structure to generate broadband Brillouin frequency comb(BFC)with double Brillouin-frequency-shift spacing.The incorporation of a reg...We present a Brillouin–Raman random fiber laser(BRRFL)with full-open linear cavity structure to generate broadband Brillouin frequency comb(BFC)with double Brillouin-frequency-shift spacing.The incorporation of a regeneration portion consisting of an erbium-doped fiber and a single-mode fiber enables the generation of broadband BFC.The dynamics of broadband BFC generation changing with the pump power(EDF and Raman)and Brillouin pump(BP)wavelength are investigated in detail,respectively.Under suitable conditions,the bidirectional BRRFL proposed can produce a flatamplitude BFC with 40.7-nm bandwidth ranging from 1531 nm to 1571.7 nm,and built-in 242-order Brillouin Stokes lines(BSLs)with double Brillouin-frequency-shift spacing.Moreover,the linewidth of single BSL is experimentally measured to be about 2.5 kHz.The broadband bidirectional narrow-linewidth BRRFL has great potential applications in optical communication,optical sensing,spectral measurement,and so on.展开更多
A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity ...A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity configuration, featuring multiwavelength output with wavelength interval of double Brillouin frequency shifts. Through simultaneously injecting the BP light and its first-order stimulated Brillouin-scattered light into the cavity, the laser output exhibits a wavelength interval of single Brillouin frequency shift. The wavelength-interval switching effect can be manipulated by controlling the power of the first-order stimulated Brillouin scattering light. The experimental results show the multiwavelength output can be switched between double Brillouin frequency shift multiwavelength emission with a broad bandwidth of approximately 60 nm and single Brillouin frequency shift multiwavelength emission of 44 nm. The flexible optically controlled random fiber laser with switchable wavelength interval makes it useful for a wide range of applications and holds significant potential in the field of wavelength-division multiplexing optical communication.展开更多
This work demonstrates the realization of a lasing in scattering media,which contains dispersive solution of Zn O nanoparticles（NPs） and laser dye 4-dicyanomethylene-2-methyle-6-（p-dimethylaminostyryl）-4H-pyran（...This work demonstrates the realization of a lasing in scattering media,which contains dispersive solution of Zn O nanoparticles（NPs） and laser dye 4-dicyanomethylene-2-methyle-6-（p-dimethylaminostyryl）-4H-pyran（DCM） in negative liquid crystals（LCs） that was injected into a cell.The lasing intensity of the dye-doped negative LC laser can be tuned from low to high if the NPs concentration is increased.The tunability of the laser is attributable to the clusters-sensitive feature in effective refractive index of the negative LCs.Such a tunable negative liquid crystal laser can be used in the fabrication of new optical sources,optical communication,and liquid crystal laser displays.展开更多
Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber...Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber loop mirrors(FLMs)is simulated by the transfer matrix method and used to provide random feedback.Multiple spikes are observed in both the simulated and measured reflection spectra.The RFL operates in a single longitudinal mode near the threshold and a time-varying multilongitudinal mode at higher pump powers.The RFL exhibits a time-varying radio-frequency spectrum.The Lévy–Gaussian distribution transition is observed,as in many RFLs.The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results.In this study,we unveil an artificial random feedback structure and pave another way for the realization of RFLs,which should be a platform for multidisciplinary studies in complex systems.展开更多
Replica symmetry breaking(RSB),as a featured phase transition between paramagnetic and spin glass state in magnetic systems,has been predicted and validated among random laser-based complex systems,which involves nume...Replica symmetry breaking(RSB),as a featured phase transition between paramagnetic and spin glass state in magnetic systems,has been predicted and validated among random laser-based complex systems,which involves numerous random modes interplayed via gain competition and exhibits disorder-induced frustration for glass behavior.However,the dynamics of RSB phase transition involving micro-state evolution of a photonic complex system have never been well investigated.Here,we report experimental evidence of transient RSB in a Brillouin random fiber laser(BRFL)-based photonic system through high-resolution unveiling of random laser mode landscape based on heterodyne technique.Thanks to the prolonged lifetime of activated random modes in BRFLs,an elaborated mapping of time-dependent statistics of the Parisi overlap parameter in both time and frequency domains was timely resolved,attributing to a compelling analogy between the transient RSB dynamics and the random mode evolution.These findings highlight that BRFL-based systems with the flexible harness of a customized photonic complex platform allow a superb opportunity for time-resolved transient RSB observation,opening new avenues in exploring fundamentals and application of complex systems and nonlinear phenomena.展开更多
Transverse localization of the optical Tamm plasmon （OTP） is studied in a metal-distributed Bragg reflector （DBR） structure with a one-dimensional disordered layer embedded at the interface between the metal and t...Transverse localization of the optical Tamm plasmon （OTP） is studied in a metal-distributed Bragg reflector （DBR） structure with a one-dimensional disordered layer embedded at the interface between the metal and the DBR. The embed- ded disordered layer induces multiple scattering and interference of light, forming the light localization in the transverse direction. This together with the formation of Tamm plasmonic modes at the metal-DBR interface （i.e., the confinement of light in the longitudinal direction）, gives birth to the so called transverse-localized Tamm plasmon. It is shown that for both transverse electric （TE） and transverse magnetic （TM） polarized light injection, the excited transverse-localized Tamm plas- mon broadens and splits the dispersion curve due to spatial incoherence in the transverse direction, thus proving the stronger light confinement especially in the TE polarized injection. By adding the gain medium, specific random lasing modes are observed. The proposed study could be an efficient way of trapping and locally enhancing light on a subwavelength scale, which is useful in applications of random lasers, optical sensing, and imaging.展开更多
Statistical properties of the erbium-doped random fiber laser(ERFL)play an important role in studying its physical attributes and advancing profound applications.Thus,there is an obvious need for thorough characteriza...Statistical properties of the erbium-doped random fiber laser(ERFL)play an important role in studying its physical attributes and advancing profound applications.Thus,there is an obvious need for thorough characterization and effective tailoring.Here,we investigate the full-bandwidth time-domain statistical properties of ERFL and achieve its tailoring through the aspect of fiber dispersion.Particularly,a narrowband ERFL is delicately designed to guarantee full-bandwidth measurement.The intensity probability density function(PDF)employed to analyze time-domain characteristics exhibits an inward deviation from the exponential distribution,indicating that correlations exist among different wavelength components.Furthermore,the effect of fiber dispersion on the temporal characteristics of ERFL is explored.The results demonstrate that dispersion accumulation breaks correlations among wavelength components,making its time-domain characteristics closer to the amplified spontaneous emission source.Conversely,dispersion compensation makes the PDF distribution converge further,leading to a more stable temporal output compared to the ERFL seed source.This work reveals the intrinsic time-domain dynamics of ERFL and provides new insights into tailoring demand-oriented temporal characteristics.展开更多
Optical fibers offer convenient access to a variety of nonlinear phenomena.However,due to their inversion symmetry,second-order nonlinear effects,such as second-harmonic generation(SHG),are challenging to achieve.Here...Optical fibers offer convenient access to a variety of nonlinear phenomena.However,due to their inversion symmetry,second-order nonlinear effects,such as second-harmonic generation(SHG),are challenging to achieve.Here,all-fiber in-core SHG with high beam quality is achieved in a random fiber laser(RFL).The fundamental wave(FW)is generated in the same RFL.The phase-matching condition is mainly achieved through an induced periodic electric field and the gain is enhanced through the passive spatiotemporal gain modulation and the extended fiber.The conversion needs no pretreatment and the average second-harmonic(SH)power reaches up to 10.06 mW,with a corresponding conversion efficiency greater than 0.04%.Moreover,a theoretical model is constructed to explain the mechanism and simulate the evolution of the SH and FW.Our work offers a simple method to generate higher brightness for in-fiber SHs,and may further provide new directions for research on all-fiberχ^((2))-based nonlinear fiber optics and RFLs.展开更多
基金financially supported by the Science and Technology Major Project of Henan Province (No.221100230300)。
文摘Vortex beams have attracted great attention due to their promising applications in the fields of high-capacity optical communication,optical micromanipulation,and quantum information processing.Here,we demonstrate vortex beams with flexible control of the topological charge and modes in a carbon dots random laser for the first time.Vortex beams with different types,including the Laguerre-Gaussian(LG),Bessel-Gaussian(BG),LG-superposition,and polarized vortex beams with topological charges up to 50,have been successfully achieved.Moreover,vortex beams can be well realized in carbon dots random lasers with different emission wavelengths covering from 465 to 612 nm.This work would not only enrich the types of vortex laser,especially for solution-processable lasers,but also provide a new route to realizing multicolor and wavelength-tunable vortex lasers.
基金support from the Natural Science Foundation of China(Grant No.61905001)Natural Science Foundation of Anhui Province,China(Grant No.1908085QF276)+1 种基金Open Fund of Key Laboratory of on Opto-Electronic Information Technology,Ministry of Education,Tianjin University,China(Grant No.2022KFKT011)Natural Science Research Project in Universities of Anhui Province,China(Grant No.2023AH050088).
文摘This paper proposes a continuously tunable random lasers(RLs)based on the gain system of cellulose nanocrystals(CNCs)-doped hydrogels and the laser dye made of Rhodamine B(Rh B).Between them,the prepared CNCs-doped hydrogels have not only a weak scattering structure that can provide excellent multiple scattering,thus yielding a large gain,but also good mechanical properties that can provide great advantages in the tuning of RL.The experimental results indicate that the RL emission wavelength blue shifts with an increase in the stretching length.The continuous tuning range reaches up to 7.1 nm when the CNCs-doped hydrogels are stretched to 400%.In addition,the proposed CNCs-doped hydrogels effectively solve the problem of the structures of traditional hydrogels,which are easily destroyed during repeated stretching and ensure good stability of RL output and tuning.The RL error is tested and found to be less than 0.5 nm,when the same length is stretched during repeated stretching.Our results provide a new approach to obtain tunable and stable RLs.Simultaneously,in combination with the good biocompatibility of CNCs-doped hydrogels,the proposed RLs demonstrated great importance in the biological field.
基金supported by the National Key Research and Development Program of China(Nos.2022YFA1404800 and 2019YFA0705000)the National Natural Science Foundation of China(Nos.12104268,12474332,12192254,92250304,and 12304325)the Natural Science Foundation of Shandong Province(Nos.ZR2024QA064 and ZR2023MA073)。
文摘In this Letter,we designed a random laser based on a nematic liquid crystal with titanium nitride nanoparticles,which has low spatial coherence,and its spatial coherence can be dynamically manipulated by the applied voltage.In a scattering environment,the speckle effect can be effectively suppressed using the random laser as the light source,and the speckle degree is controlled by the applied voltage.Moreover,with the decrease of the spatial coherence of the random laser,the imaging edges become blurred.We provided a quantitative way to optimize the image quality between uniformity and edge sharpness while improving the signal-to-noise ratio.
基金supported by the National Natural Science Foundation of China(Nos.12174002,11874012,11874126,and 51771186)the Excellent Scientific Research and Innovation Team of Anhui Province(No.2022AH010003)+3 种基金the Key Research and Development Plan of Anhui Province(No.202104a05020059)the Innovation Project for the ReturnedOverseasScholarsofAnhuiProvince(No.2021LCX011)the University Synergy Innovation Program of Anhui Province(No.GXXT-2020-052)the Anhui Young Wanjiang Scholars Talent Project(No.Z010118167)。
文摘Random lasers are a type of lasers that lack typical resonator structures,offering benefits such as easy integration,low cost,and low spatial coherence.These features make them popular for speckle-free imaging and random number generation.However,due to their high threshold and phase instability,the production of picosecond random lasers has still been a challenge.In this work,we have developed three dyes incorporating polymer optical fibers doped with various scattering nanoparticles to produce short-pulsed random fiber lasers.Notably,stable picosecond random laser emission lasting600 ps is observed at a low pump energy of 50μJ,indicating the gain-switching mechanism.Population inversion and gain undergo an abrupt surge as the intensity of the continuously pumped light nears the threshold level.When the intensity of the continuously pumped light reaches a specific value,the number of inversion populations in the“scattering cavity”surpasses the threshold rapidly.Simulation results based on a model that considers power-dependent gain saturation confirmed the above phenomenon.This research helps expand the understanding of the dynamics behind random medium-stimulated emission in random lasers and opens up possibilities for mode locking in these systems.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60278016 and 10464002.
文摘We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and non-pump areas. The dependence of lasing modes on the pump area is qualitatively explained by means of the model in which the lasing is ascribed to the interaction of the complex localized modes in the active random medium with local aperiodic quasi-structure with appropriate pump light. There exist different pump sizes for lasing with different modes. As the pump size decreases in this random system, the pump threshold of the lasing modes increases. There are different lasing modes in different excitation regions in this random system. This gives us some information about the dependence of lasing modes on pump areas in active random media.
基金Project supported by the Fundamental Research Fund for the Central Universities of Ministry of Education of China (Grant No.2010MS041)the National Natural Science Foundation of China (Grant No.60778003)the Science Foundation of China Academy of Engineering Physics NSAF (Grant No.10876010)
文摘Terahertz （THz） random lazing is studied numerically for two-dimensional disordered media made of ruby grains with a three-level atomic system. A method via the adjustment of the pumping area to control the polarization of the THz wave is proposed. Computed results reveal that transverse electric THz lasing modes could occur if pumping is supplied on the whole medium, while transverse magnetic THz lasing modes could occur if pumping is appropriately supplied on a partial area of the medium.
基金supported by the National Natural Science Foundation of China(Grant Nos.61405040,61675027,51622205,51432005,61505010,and 51502018)the National Key Research and Development Project,Ministry of Science and Technology,China(Grant No 2016YFA0202703)+2 种基金the National Postdoctoral Program for Innovative Talents,China(Grant No.BX201600040)the China Postdoctoral Science Foundation(Grant No.2016M600976)the“Thousand Talents”Program of China for Pioneering Researchers and Innovative Teams
文摘Flexible electrically pumped random laser（RL） based on ZnO nanowires is demonstrated for the first time to our knowledge. The ZnO nanowires each with a length of 5 μm and an average diameter of 180 nm are synthesized on flexible substrate（ITO/PET） by a simple hydrothermal method. No obvious visible defect-related-emission band is observed in the photoluminescence（PL） spectrum, indicating that the ZnO nanowires grown on the flexible ITO/PET substrate have few defects. In order to achieve electrically pumped random lasing with a lower threshold, the metal–insulator–semiconductor（MIS） structure of Au/SiO2/ZnO on ITO/PET substrate is fabricated by low temperature process. With sufficient forward bias, the as-fabricated flexible device exhibits random lasing, and a low threshold current of ～ 11.5 m A and high luminous intensity are obtained from the ZnO-based random laser. It is believed that this work offers a case study for developing the flexible electrically pumped random lasing from ZnO nanowires.
基金supported by the National Natural Science Foundation of China(No.51673178,No.51273186,No.21574120,No.11874012,No.11404087,and No.11574070)Basic Research Fund for the Central Universities(No.WK2060200012)+3 种基金Science and Technological Fund of Anhui Province for Outstanding Youth(No.1608085J01)Fundamental Research Funds for the Central Universities of China,Postdoctoral Science Foundation(No.2015M571918 and No.2017T100442)the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sk lodowska-Curie Grant Agreement(No.744817)the Project of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(No.18zxhk10)
文摘Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide(DPP) which possesses POSS as scatteres experimentally performs strong NFSE, which confirms the physical simulation results. Moreover, coherent random laser is triggered from the DPP aggregates in carbon disulfide. It is the NFSE of POSS NPs connected to both ends of DPP through covalent bonds and the NFSE of their aggregation thanks to DPP’s aggregation that is responsible for the coherent random laser. So, this work develops a method to improve weak scattering of system through construction of molecules, and opens a road to a variety of novel interdisciplinary investigations, involving molecular designing for disordered photonics.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0205800)the National Natural Science Foundation of China(Grant Nos.11734005,61307066,and 61450110442)+3 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20130630)the Doctoral Fund of Ministry of Education of China(Grant No.20130092120024)the Innovation Fund of School of Electronic Science and Engineering,Southeast University,China(Grant No.2242015KD006)the Scientific Research Foundation of Graduate School of Southeast University,China(Grant Nos.YBJJ1513 and YBJJ1613)
文摘Here,a plasmon-enhanced random laser was achieved by incorporating gold nanostars（NS） into disordered polymer and Cd Se/Zn S quantum dots（QDs） gain medium films,in which the surface plasmon resonance of gold NS can greatly enhance the scattering cross section and bring a large gain volume.The random distribution of gold NS in the gain medium film formed a laser-mode resonator.Under a single-pulse pumping,the scattering center of gold NS-based random laser exhibits enhanced performance of a lasing threshold of 0.8 m J/cm^2 and a full width as narrow as 6 nm at half maximum.By utilizing the local enhancement characteristic of the electric field at the sharp apexes of the gold NS,the emission intensity of the random laser was increased.In addition,the gold NS showed higher thermal stability than the silver nanoparticles,withstanding high temperature heating up to 200？C.The results of metal nanostructures with enriched hot spots and excellent temperature stability have tremendous potential applications in the fields of biological identification,medical diagnostics,lighting,and display devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.62375040 and 11974071)the Sichuan Science and Technology Program(Grant Nos.2022ZYD0108 and 2023JDRC0030).
文摘Optical memory effect-based speckle-correlated technology has been developed for reconstructing hidden objectsfrom disordered speckle patterns,achieving imaging through scattering layers.However,the lighting efficiency and fieldof view of existing speckle-correlated imaging systems are limited.Here,a near-infrared low spatial coherence fiberrandom laser illumination method is proposed to address the above limitations.Through the utilization of random Rayleighscattering within dispersion-shifted fibers to provide feedback,coupled with stimulated Raman scattering for amplification,a near-infrared fiber random laser exhibiting a high spectral density and extremely low spatial coherence is generated.Based on the designed fiber random laser,speckle-correlated imaging through scattering layers is achieved,with highlighting efficiency and a large imaging field of view.This work improves the performance of speckle-correlated imagingand enriches the research on imaging through scattering medium.
基金supported by the National Natural Science Foundation of China (Grant No.62105180)the Natural Science Foundation of Shandong Province (Grant Nos.ZR2020MF110 and ZR2020MF118)+2 种基金the Taishan Scholar Foundation of Shandong Province (Grant No.tsqn202211027)the Qilu Young Scholar Program of Shandong Universitythe National Grant Program for High-level Returning Oversea Talents (2023).
文摘The optical rogue wave(RW),known as a short-lived extraordinarily high amplitude dynamics phenomenon with small appearing probabilities,plays an important role in revealing and understanding the fundamental physics of nonlinear wave propagations in optical systems.The random fiber laser(RFL),featured with cavity-free and“modeless”structure,has opened up new avenues for fundamental physics research and potential practical applications combining nonlinear optics and laser physics.Here,the extreme event of optical RW induced by noise-driven modulation instability that interacts with the cascaded stimulated Brillouin scattering,the quasi-phase-matched four-wave mixing as well as the random mode resonance process is observed in a Brillouin random fiber laser comb(BRFLC).Temporal and statistical characteristics of the RWs concerning their emergence and evolution are experimentally explored and analyzed.Specifically,temporally localized structures with high intensities including chair-like pulses with a sharp leading edge followed by a trailing plateau appear frequently in the BRFLC output,which can evolve to chair-like RW pulses with adjustable pulse duration and amplitude under controlled conditions.This investigation provides a deep insight into the extreme event of RWs and paves the way for RW manipulation for its generation and elimination in RFLs through adapted laser configuration.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62175116 and 91950105)the 1311 Talent Plan of Nanjing University of Posts and Telecommunications, Chinathe Postgraduate Research & Practice Innovation Program, Jiangsu Province, China (Grant No. SJCX21_0276)
文摘We present a Brillouin–Raman random fiber laser(BRRFL)with full-open linear cavity structure to generate broadband Brillouin frequency comb(BFC)with double Brillouin-frequency-shift spacing.The incorporation of a regeneration portion consisting of an erbium-doped fiber and a single-mode fiber enables the generation of broadband BFC.The dynamics of broadband BFC generation changing with the pump power(EDF and Raman)and Brillouin pump(BP)wavelength are investigated in detail,respectively.Under suitable conditions,the bidirectional BRRFL proposed can produce a flatamplitude BFC with 40.7-nm bandwidth ranging from 1531 nm to 1571.7 nm,and built-in 242-order Brillouin Stokes lines(BSLs)with double Brillouin-frequency-shift spacing.Moreover,the linewidth of single BSL is experimentally measured to be about 2.5 kHz.The broadband bidirectional narrow-linewidth BRRFL has great potential applications in optical communication,optical sensing,spectral measurement,and so on.
基金Poject supported by the National Natural Science Foundation of China(Grant Nos.62175116 and 62311530343)the Postgraduate Research Innovation Program of Jiangsu Province,China(Grant No.KYCX22_0913)。
文摘A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity configuration, featuring multiwavelength output with wavelength interval of double Brillouin frequency shifts. Through simultaneously injecting the BP light and its first-order stimulated Brillouin-scattered light into the cavity, the laser output exhibits a wavelength interval of single Brillouin frequency shift. The wavelength-interval switching effect can be manipulated by controlling the power of the first-order stimulated Brillouin scattering light. The experimental results show the multiwavelength output can be switched between double Brillouin frequency shift multiwavelength emission with a broad bandwidth of approximately 60 nm and single Brillouin frequency shift multiwavelength emission of 44 nm. The flexible optically controlled random fiber laser with switchable wavelength interval makes it useful for a wide range of applications and holds significant potential in the field of wavelength-division multiplexing optical communication.
基金Project supported by the Doctoral Science Research Start-up Funding of Guizhou Normal University,China(Grant No.11904-0514162)the National Natural Science Foundation of China(Grant No.11474021)
文摘This work demonstrates the realization of a lasing in scattering media,which contains dispersive solution of Zn O nanoparticles（NPs） and laser dye 4-dicyanomethylene-2-methyle-6-（p-dimethylaminostyryl）-4H-pyran（DCM） in negative liquid crystals（LCs） that was injected into a cell.The lasing intensity of the dye-doped negative LC laser can be tuned from low to high if the NPs concentration is increased.The tunability of the laser is attributable to the clusters-sensitive feature in effective refractive index of the negative LCs.Such a tunable negative liquid crystal laser can be used in the fabrication of new optical sources,optical communication,and liquid crystal laser displays.
基金supported by the National Key R&D Program of China(Grant No.2023YFE0105800)the National Natural Science Foundation of China(Grant Nos.62275093 and 61775074)the Key R&D Program of Hubei Province(Grant No.2021BAA036).
文摘Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber loop mirrors(FLMs)is simulated by the transfer matrix method and used to provide random feedback.Multiple spikes are observed in both the simulated and measured reflection spectra.The RFL operates in a single longitudinal mode near the threshold and a time-varying multilongitudinal mode at higher pump powers.The RFL exhibits a time-varying radio-frequency spectrum.The Lévy–Gaussian distribution transition is observed,as in many RFLs.The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results.In this study,we unveil an artificial random feedback structure and pave another way for the realization of RFLs,which should be a platform for multidisciplinary studies in complex systems.
基金National Natural Science Foundation of China(NSFC)(62275146,61905138)Science and Technology Commission of Shanghai Municipality(20ZR1420800)+2 种基金State Key Laboratory of Advanced Optical Communication Systems and Networks(2022GZKF004)Shanghai Professional Technology Platform(19DZ2294000)111 Project(D20031).
文摘Replica symmetry breaking(RSB),as a featured phase transition between paramagnetic and spin glass state in magnetic systems,has been predicted and validated among random laser-based complex systems,which involves numerous random modes interplayed via gain competition and exhibits disorder-induced frustration for glass behavior.However,the dynamics of RSB phase transition involving micro-state evolution of a photonic complex system have never been well investigated.Here,we report experimental evidence of transient RSB in a Brillouin random fiber laser(BRFL)-based photonic system through high-resolution unveiling of random laser mode landscape based on heterodyne technique.Thanks to the prolonged lifetime of activated random modes in BRFLs,an elaborated mapping of time-dependent statistics of the Parisi overlap parameter in both time and frequency domains was timely resolved,attributing to a compelling analogy between the transient RSB dynamics and the random mode evolution.These findings highlight that BRFL-based systems with the flexible harness of a customized photonic complex platform allow a superb opportunity for time-resolved transient RSB observation,opening new avenues in exploring fundamentals and application of complex systems and nonlinear phenomena.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61575040 and 61635005)the 111 Project,China(Grant No.B14039)
文摘Transverse localization of the optical Tamm plasmon （OTP） is studied in a metal-distributed Bragg reflector （DBR） structure with a one-dimensional disordered layer embedded at the interface between the metal and the DBR. The embed- ded disordered layer induces multiple scattering and interference of light, forming the light localization in the transverse direction. This together with the formation of Tamm plasmonic modes at the metal-DBR interface （i.e., the confinement of light in the longitudinal direction）, gives birth to the so called transverse-localized Tamm plasmon. It is shown that for both transverse electric （TE） and transverse magnetic （TM） polarized light injection, the excited transverse-localized Tamm plas- mon broadens and splits the dispersion curve due to spatial incoherence in the transverse direction, thus proving the stronger light confinement especially in the TE polarized injection. By adding the gain medium, specific random lasing modes are observed. The proposed study could be an efficient way of trapping and locally enhancing light on a subwavelength scale, which is useful in applications of random lasers, optical sensing, and imaging.
基金supported by the National Natural Science Foundation of China(No.62075030)the Ministry of Science and Technology(No.DL2023167001L)+1 种基金the Sichuan Science and Technology Program(No.2023YFSY0058)the 111 Project(No.B14039)。
文摘Statistical properties of the erbium-doped random fiber laser(ERFL)play an important role in studying its physical attributes and advancing profound applications.Thus,there is an obvious need for thorough characterization and effective tailoring.Here,we investigate the full-bandwidth time-domain statistical properties of ERFL and achieve its tailoring through the aspect of fiber dispersion.Particularly,a narrowband ERFL is delicately designed to guarantee full-bandwidth measurement.The intensity probability density function(PDF)employed to analyze time-domain characteristics exhibits an inward deviation from the exponential distribution,indicating that correlations exist among different wavelength components.Furthermore,the effect of fiber dispersion on the temporal characteristics of ERFL is explored.The results demonstrate that dispersion accumulation breaks correlations among wavelength components,making its time-domain characteristics closer to the amplified spontaneous emission source.Conversely,dispersion compensation makes the PDF distribution converge further,leading to a more stable temporal output compared to the ERFL seed source.This work reveals the intrinsic time-domain dynamics of ERFL and provides new insights into tailoring demand-oriented temporal characteristics.
基金supported by the Beijing Natural Science Foundation(Grant No.L241021)the National Key Research and Development Program of China(Grant No.2023YFB4604501)the National Natural Science Foundation of China(Grant Nos.62475132 and 62122040)。
文摘Optical fibers offer convenient access to a variety of nonlinear phenomena.However,due to their inversion symmetry,second-order nonlinear effects,such as second-harmonic generation(SHG),are challenging to achieve.Here,all-fiber in-core SHG with high beam quality is achieved in a random fiber laser(RFL).The fundamental wave(FW)is generated in the same RFL.The phase-matching condition is mainly achieved through an induced periodic electric field and the gain is enhanced through the passive spatiotemporal gain modulation and the extended fiber.The conversion needs no pretreatment and the average second-harmonic(SH)power reaches up to 10.06 mW,with a corresponding conversion efficiency greater than 0.04%.Moreover,a theoretical model is constructed to explain the mechanism and simulate the evolution of the SH and FW.Our work offers a simple method to generate higher brightness for in-fiber SHs,and may further provide new directions for research on all-fiberχ^((2))-based nonlinear fiber optics and RFLs.
