Time Division Multiplexing-Passive Optical Networks(TDM-PONs)play a vital role in Fiberto-the-Home(FTTH)deployments.To improve the service quality of home networks,FTTH is expanding to the Fiber-to-the-Room(FTTR)scena...Time Division Multiplexing-Passive Optical Networks(TDM-PONs)play a vital role in Fiberto-the-Home(FTTH)deployments.To improve the service quality of home networks,FTTH is expanding to the Fiber-to-the-Room(FTTR)scenario,where fibers are deployed to connect individual rooms(i.e.,Fiber In-premises Network(FIN)in the ITU-T G.9940 standard).In this scenario,a point-to-multipoint(P2MP)fiber network is deployed as FTTR FIN to offer gigabit access to each room,which forms a two-tier cascaded network together with the FTTH segment.To optimize the capacity utilization of the cascaded network and reduce the overall system cost,a centralized architecture,known as Centralized Fixed Access Network(C-FAN),has been introduced.C-FAN centralizes the medium access control(MAC)modules of both the FTTH and FTTR networks at the FTTH’s Optical Line Terminal(OLT)for unified control and management of the cascaded network.We develop a unified bandwidth scheduling protocol by extending the ITU-T PON standard for both the upstream and downstream directions of C-FAN.We also propose a unified dynamic bandwidth allocation(UDBA)algorithm for efficient bandwidth allocation for multiple traffic flows in the two-tier cascaded network.Simulations are conducted to evaluate the performance of the proposed control protocol and the UDBA algorithm.The results show that,in comparison to the conventional DBA algorithm,the UDBA algorithm can utilize upstream bandwidth more efficiently to reduce packet delay and loss,without adversely impacting downstream transmission performance.展开更多
We demonstrate an integrating sphere to cool~(87)Rb atoms and measure the recoil-induced resonance and electromagnetically induced absorption spectrum.We measure the relationship between their linewidth and light shif...We demonstrate an integrating sphere to cool~(87)Rb atoms and measure the recoil-induced resonance and electromagnetically induced absorption spectrum.We measure the relationship between their linewidth and light shift with variation of the detuning and power of the cooling laser and study the performance of the diffuse laser cooling mechanism by the absorption linewidth radio?ν_E/?ν_R and light shift|?_R-?_E|using nonlinear spectroscopy.Specifically,when?ν_E/?ν_R reaches a value of 1.57,the temperature and number of cold atoms achieve the optimal cooling effect.This characterization of absorption linewidth and light shift will provide a method to estimate whether diffuse light cooling achieves the best cooling effect,contributing to the future development of isotropic laser cooling for application in quantum sensing.展开更多
Semiconductor colloidal quantum wells(CQWs)with atomic-precision layer thickness are rapidly gaining attention for next-generation optoelectronic applications due to their tunable optical and electronic properties.In ...Semiconductor colloidal quantum wells(CQWs)with atomic-precision layer thickness are rapidly gaining attention for next-generation optoelectronic applications due to their tunable optical and electronic properties.In this study,we investigate the dielectric and optical characteristics of CdSe CQWs with monolayer numbers ranging from 2 to 7,synthesized via thermal injection and atomic layer(c-ALD)deposition techniques.Through a combination of spectroscopic ellipsometry(SE)and first-principles calculations,we demonstrate the significant tunability of the bandgap,refractive index,and extinction coefficient,driven by quantum confinement effects.Our results show a decrease in bandgap from 3.1 to 2.0 eV as the layer thickness increases.Furthermore,by employing a detailed analysis of the absorption spectra,accounting for exciton localization and asymmetric broadening,we precisely capture the relationship between monolayer number and exciton binding energy.These findings offer crucial insights for optimizing CdSe CQWs in optoelectronic device design by leveraging their layer-dependent properties.展开更多
It is a pleasure to contribute a commentary on the very interesting review by Dr.Orcioli-Silva and colleagues1 on the simultaneous measurements of cerebral cortex and muscle tissue oxygenation during exercise in healt...It is a pleasure to contribute a commentary on the very interesting review by Dr.Orcioli-Silva and colleagues1 on the simultaneous measurements of cerebral cortex and muscle tissue oxygenation during exercise in healthy adults using near-infrared spectroscopy(NIRS).The first NIRS measurements of the cerebral cortex and muscle were performed on humans in 19772 and 1982,3 respectively.展开更多
This study presents a detailed photometric and spectroscopic analysis of the W UMa-type binary NR Cam,using data from the Transiting Exoplanet Survey Satellite(TESS)and ground-based observations.The light curves exhib...This study presents a detailed photometric and spectroscopic analysis of the W UMa-type binary NR Cam,using data from the Transiting Exoplanet Survey Satellite(TESS)and ground-based observations.The light curves exhibit significant variable,with a negative correlation between the brightness of the two maxima—a characteristic of W UMa-type binaries typically attributed to magnetic activity.To explain this behavior,we incorporated a starspot model into our Wilson–Devinney analysis.Our results confirm that NR Cam is a W-subtype,moderately contact binary with a low mass ratio of q=5.75(±0.03)and a fill-out factor of f=33.4(±3.1)%.We also analyzed the orbital period variation using all available times of minima.The resulting O−C diagram reveals a long-term decreasing trend in the orbital period at a rate of dP/dt=−5.18(±0.02)×10^(-8) day yr^(-1),superimposed with a periodic oscillation characterized by an amplitude of A_(3)=0.0019(±0.0001)day and an oscillation period of P_(3)=7.776(±0.003)yr.The long-term decrease is likely due to mass transfer between the binary components,with an estimated mass transfer rate of dM_(2)/dt=1.33(±0.01)×10^(-8)M_(⊙)yr^(-1).The periodic oscillations are likely driven by the light-travel time effect caused by a tertiary companion,with a minimum mass of M_(3)=0.0956(1)M_(⊙)and a maximum separation of 3.841(6)au.Additionally,we considered the possibility that the periodic variation could result from changes in the gravitational quadrupole moment due to magnetic activity cycles,as described by the Applegate mechanism.Our findings confirm that NR Cam is an active binary system,where magnetic activity plays a significant role in its orbital evolution.These results contribute to our understanding of the magnetic dynamics and evolutionary processes in contact binary systems.展开更多
The integrated waveguide polarizer is essential for photonic integrated circuits,and various designs of waveguide polarizers have been developed.As the demand for dense photonic integration increases rapidly,new strat...The integrated waveguide polarizer is essential for photonic integrated circuits,and various designs of waveguide polarizers have been developed.As the demand for dense photonic integration increases rapidly,new strategies to minimize the device size are needed.In this paper,we have inversely designed an integrated transverse electric pass(TE-pass)polarizer with a footprint of 2.88μm×2.88μm,which is the smallest footprint ever achieved.A direct binary search algorithm is used to inversely design the device for maximizing the transverse electric(TE)transmission while minimizing transverse magnetic(TM)transmission.Finally,the inverse-designed device provides an average insertion loss of 0.99 dB and an average extinction ratio of 33 dB over a wavelength range of 100 nm.展开更多
Atherosclerosis(AS),a chronic vascular lesion,constitutes the primary pathological basis for a variety of cardiovascular diseases that account for 85%of total cardiovascular mortality.The accurate identification of AS...Atherosclerosis(AS),a chronic vascular lesion,constitutes the primary pathological basis for a variety of cardiovascular diseases that account for 85%of total cardiovascular mortality.The accurate identification of AS is of critical significance for early clinical diagnosis and therapeutic interventions for associated diseases.Herein,we report a changeableπ-conjugated probe(ASOCl-1)capable of specific AS imaging with resistance to serum protein interference and microenvironmental perturbations.ASOCl-1 itself was non-conjugated and non-fluorescent.Upon the activation by inflammatory biomarker hypochlorite(OCl^(−)),the probe underwent a molecular rearrangement to generate a near-infrared fluorophore oxazine,with environmental-insusceptible response and anti-interference from serum protein.ASOCl-1 has been used to image OCl^(−)inside foam cells,a type of cell derived from macrophages at the AS sites.Most importantly,ASOCl-1 could achieve in vivo,ex vivo and slice imaging of AS mice.The satisfactory imaging performance and anti-interference capability of ASOCl-1 make it a potential tool for AS imaging diagnosis and disease progression monitoring.展开更多
This paper mainly focuses on the influence of colloidal silica polishing on the damage performance of fused silica optics. In this paper, nanometer sized colloidal silica and micron sized ceria are used to polish fuse...This paper mainly focuses on the influence of colloidal silica polishing on the damage performance of fused silica optics. In this paper, nanometer sized colloidal silica and micron sized ceria are used to polish fused silica optics. The colloidal silica polished samples and ceria polished samples exhibit that the root-mean-squared （RMS） average surface roughness values are 0.7 nm and 1.0 rim, respectively. The subsurface defects and damage performance of the polished optics are analyzed and discussed. It is revealed that colloidal silica polishing will introduce much fewer absorptive con- taminant elements and subsurface damages especially no trailing indentation fracture. The 355-nm laser damage test reveals that each of the fused silica samples polished with colloidal silica has a much higher damage threshold and lower damage density than ceria polished samples. Colloidal silica polishing is potential in manufacturing high power laser optics.展开更多
Laser-induced damage in fused silica optics greatly restricts the performances of laser facilities. Gray haze damage,which is always initiated on ceria polished optics, is one of the most important damage morphologies...Laser-induced damage in fused silica optics greatly restricts the performances of laser facilities. Gray haze damage,which is always initiated on ceria polished optics, is one of the most important damage morphologies in fused silica optics.In this paper, the laser-induced gray haze damages of four fused silica samples polished with CeO2, Al2O3, ZrO2, and colloidal silica slurries are investigated. Four samples all present gray haze damages with much different damage densities.Then, the polishing-induced contaminant and subsurface damages in four samples are analyzed. The results reveal that the gray haze damages could be initiated on the samples without Ce contaminant and are inclined to show a tight correlation with the shallow subsurface damages.展开更多
Due to ever-increasing concerns about safety issues in using Li ionic batteries,solid electrolytes have extensively explored.The Li-rich antiperovskite Li_(3)OBr has been considered as a promising solid electrolyte ca...Due to ever-increasing concerns about safety issues in using Li ionic batteries,solid electrolytes have extensively explored.The Li-rich antiperovskite Li_(3)OBr has been considered as a promising solid electrolyte candidate,but it still suffers challenges to achieve a high ionic conductivity owing to the high intrinsic symmetry of the crystal lattice.Herein,we presented a design strategy that introduces various point defects and grain boundaries to break the high lattice symmetry of Li_(3)OBr crystal,and their effect and microscopic mechanism of promoting the migration of Li-ion were explored theoretically.It has been found that Li_(i)are the dominant defects responsible for the fast Li-ion diffusion in bulk Li_(3)OBr and its surface,but they are easily trapped by the grain boundaries,leading to the annihilating of the Frenkel defect pair V'_(Li)+Li_(i),and thus limits the V'_(Li)diffusion at the grain boundaries.The V_(Br)defect near the grain boundaries can effectively drive V'_(Li)across the grain boundary,thereby converting the carrier of Li^(+)migration from Li,in the bulk and surface to V'_(Li)at the grain boundary,and thus improving the ionic conductivity in the whole Li_(3)OBr crystal.This work provides a comprehensive insight into the Li^(+)transport and conduction mechanism in the Li_(3)OBr electrolyte.It opens a new way of improving the conductivity for all-solid-state Li electrolyte material through the defect design.展开更多
V0405 Dra is a W UMa-type binary star.Based on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the system.The orbital period study reveals that the O-C curve for V0405 ...V0405 Dra is a W UMa-type binary star.Based on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the system.The orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by an amplitude of A_(3)=0.0032 day and a period of P_(3)=1.413 years.The orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2013 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact binary.The fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum loss.With further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries.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
Environmental pollution,such as water contamination,is a critical issue that must be absolutely addressed.Here,three different morphologies of tungsten-based photocatalysts(WO_(3)nanorods,WO_(3)/WS_(2)nanobricks,WO_(3...Environmental pollution,such as water contamination,is a critical issue that must be absolutely addressed.Here,three different morphologies of tungsten-based photocatalysts(WO_(3)nanorods,WO_(3)/WS_(2)nanobricks,WO_(3)/WS_(2)nanorods)are made using a simple hydrothermal method by changing the solvents(H_(2)O,DMF,aqueous HCl solution).The as-prepared nanocatalysts have excellent thermal stability,large porosity,and high hydrophilicity.The results show all materials have good photocatalytic activity in aqueous media,with WO_(3)/WS_(2)nanorods(NRs)having the best activity in the photodegradation of bisphenol A(BPA)under visible-light irradiation.This may originate from increased migration of charge carriers and effective prevention of electron–hole recombination in WO_(3)/WS_(2)NRs,whereby this photocatalyst is able to generate more reactive·OH and·O_(2)^(–)species,leading to greater photocatalytic activity.About 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO_(3)/WS_(2)NRs and 5.0 mg/L BPA at pH 7.0.Additionally,the optimal conditions(pH,catalyst dosage,initial BPA concentration)for WO_(3)/WS_(2)NRs are also elaborately investigated.These rod-like heterostructures are expressed as potential catalysts with excellent photostability,efficient reusability,and highly active effectivity in different types of water.In particular,the removal efficiency of BPA by WO_(3)/WS_(2)NRs reduces by only 1.5% after five recycling runs and even reaches 89.1%in contaminated lake water.This study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources,which is advantageous to various applications in environmental remediation.展开更多
In thiswork,the perovskite LaZnO_(3) was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole(SMZ)antibiotics under visible light activation.SMZ was almost completely degraded(99.2...In thiswork,the perovskite LaZnO_(3) was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole(SMZ)antibiotics under visible light activation.SMZ was almost completely degraded(99.2%±0.3%)within 4 hr by photocatalyst LaZnO_(3) at the optimal dosage of 1.1 g/L,with amineralization proportion of 58.7%±0.4%.The efficient performance of LaZnO_(3) can be attributed to itswide-range light absorption and the appropriate energy band edge levels,which facilitate the formation of active agents such as·O_(2)^(−),h^(+),and·OH.The integration of RP-HPLC/Q-TOF-MS and DFT-based computational techniques revealed three degradation pathways of SMZ,which were initiated by the deamination reaction at the aniline ring,the breakdown of the sulfonamidemoieties,and a process known as Smile-type rearrangement and SO2 intrusion.Corresponding toxicity of SMZ and the intermediateswere analyzed by quantitative structure activity relationship(QSAR),indicating the effectiveness of LaZnO_(3)-based photocatalysis in preventing secondary pollution of the intermediates to the ecosystem during the degradation process.The visible-light-activated photocatalyst LaZnO_(3) exhibited efficient performance in the occurrence of inorganic anions and maintained high durability across multiple recycling tests,making it a promising candidate for practical antibiotic treatment.展开更多
Cubic phase Tm^(3+)/Yb^(3+):Y_(2)O_(3) and Tm^(3+)/Yb^(3+)/Gd^(3+):Y_(2)O_(3) phosphors were prepared by low temperature combustion technique for upconversion emission in UV-visible range.The 980 nm excitation has gen...Cubic phase Tm^(3+)/Yb^(3+):Y_(2)O_(3) and Tm^(3+)/Yb^(3+)/Gd^(3+):Y_(2)O_(3) phosphors were prepared by low temperature combustion technique for upconversion emission in UV-visible range.The 980 nm excitation has generated UV emission at 314 nm in tridoped phosphor due to the energy transfer from Tm^(3+) to Gd^(3+)ion.Characteristic emission bands from Tm^(3+) are also observed in both the phosphors.Thermally coupled Stark sublevels ^(1)G_(4(a))(476 nm) and ^(1)G_(4(b))(488 nm) of Tm^(3+) ion were utilised for optical thermometry using fluorescent intensity ratio(FIR) method.The result shows that maximum absolute sensitivity in tridoped phosphor is observed to be 1.33 × 10^(-3) K^(-1) at 298 K.Moreover,temperature rise of phosphor at various pump power densities was also measured and it is estimated to achieve 407 K at the pump power density of 38.46 W/cm^(2).展开更多
The laser-induced damage threshold(LIDT) of optical coating is a limited factor for development of a high peak power laser. The automatic damage testing facility was built to determine the LIDT of optics at 1 064 nm a...The laser-induced damage threshold(LIDT) of optical coating is a limited factor for development of a high peak power laser. The automatic damage testing facility was built to determine the LIDT of optics at 1 064 nm and 355 nm.. The cleanning and processing procedure of the substrate and coating technique were improved, and the damage resistance of high-reflective coating at 1 064 nm was increased.展开更多
In this review paper on heavy ion inertial fusion(HIF),the state-of-the-art scientific results are presented and discussed on the HIF physics,including physics of the heavy ion beam(HIB)transport in a fusion reactor,t...In this review paper on heavy ion inertial fusion(HIF),the state-of-the-art scientific results are presented and discussed on the HIF physics,including physics of the heavy ion beam(HIB)transport in a fusion reactor,the HIBs-ion illumination on a direct-drive fuel target,the fuel target physics,the uniformity of the HIF target implosion,the smoothing mechanisms of the target implosion non-uniformity and the robust target implosion.The HIB has remarkable preferable features to release the fusion energy in inertial fusion:in particle accelerators HIBs are generated with a high driver efficiency of~30%-40%,and the HIB ions deposit their energy inside of materials.Therefore,a requirement for the fusion target energy gain is relatively low,that would be~50-70 to operate a HIF fusion reactor with the standard energy output of 1 GWof electricity.The HIF reactor operation frequency would be~10-15 Hz or so.Several-MJ HIBs illuminate a fusion fuel target,and the fuel target is imploded to about a thousand times of the solid density.Then the DT fuel is ignited and burned.The HIB ion deposition range is defined by the HIB ions stopping length,which would be~1 mm or so depending on the material.Therefore,a relatively large density-scale length appears in the fuel target material.One of the critical issues in inertial fusion would be a spherically uniform target compression,which would be degraded by a non-uniform implosion.The implosion non-uniformity would be introduced by the Rayleigh-Taylor(R-T)instability,and the large densitygradient-scale length helps to reduce the R-T growth rate.On the other hand,the large scale length of the HIB ions stopping range suggests that the temperature at the energy deposition layer in a HIF target does not reach a very-high temperature:normally about 300 eV or so is realized in the energy absorption region,and that a direct-drive target would be appropriate in HIF.In addition,the HIB accelerators are operated repetitively and stably.The precise control of the HIB axis manipulation is also realized in the HIF accelerator,and the HIB wobbling motion may give another tool to smooth the HIB illumination non-uniformity.The key issues in HIF physics are also discussed and presented in the paper.展开更多
Disordered-structure crystals have drawn increasing attention as promising ultrashort laser material hosts owing to their broad linewidth.Herein,a novel disordered Nd:YSr_(3)(PO_(4))_(3)(Nd:YSP)crystal with good quali...Disordered-structure crystals have drawn increasing attention as promising ultrashort laser material hosts owing to their broad linewidth.Herein,a novel disordered Nd:YSr_(3)(PO_(4))_(3)(Nd:YSP)crystal with good quality was successfully grown via the Czochralski pulling technique.The absorption and fluorescence spectra of the Nd:YSP single crystal were recorded at ambient temperature.The maximum absorption cross section for Nd:YSP single crystal is found to be approximately 3.89×10^(-20) cm^(2).The stimulated emission cross section for Nd:YSP crystal at~1060 nm was determined to be 7.64×10^(20) cm^(2) with the full width half maximum value of 22 nm.The fluorescence lifetime of the Nd3+ions in the Nd:YSP crystal is fitted to be 288μs.Diode-pumped continuous-wave laser operation is firstly realized at approximately 1060 nm.The maximum output power value from the Nd:YSP crystal is 714 mW,corresponding to a slope efficiency of-12.8%.The results indicate that the Nd:YSP crystal with a disordered structure may be a promising disordered laser host.展开更多
基金supported by National Nature Science Founding of China(62101372)Open Fund of IPOC(BUPT,IPOC2022A07)+1 种基金State Key Laboratory of Advanced Optical Communication Systems and Networks(2023GZKF11)Leading Youth Talents of Innovation and Entrepreneurship of Gusu(ZXL2023162).
文摘Time Division Multiplexing-Passive Optical Networks(TDM-PONs)play a vital role in Fiberto-the-Home(FTTH)deployments.To improve the service quality of home networks,FTTH is expanding to the Fiber-to-the-Room(FTTR)scenario,where fibers are deployed to connect individual rooms(i.e.,Fiber In-premises Network(FIN)in the ITU-T G.9940 standard).In this scenario,a point-to-multipoint(P2MP)fiber network is deployed as FTTR FIN to offer gigabit access to each room,which forms a two-tier cascaded network together with the FTTH segment.To optimize the capacity utilization of the cascaded network and reduce the overall system cost,a centralized architecture,known as Centralized Fixed Access Network(C-FAN),has been introduced.C-FAN centralizes the medium access control(MAC)modules of both the FTTH and FTTR networks at the FTTH’s Optical Line Terminal(OLT)for unified control and management of the cascaded network.We develop a unified bandwidth scheduling protocol by extending the ITU-T PON standard for both the upstream and downstream directions of C-FAN.We also propose a unified dynamic bandwidth allocation(UDBA)algorithm for efficient bandwidth allocation for multiple traffic flows in the two-tier cascaded network.Simulations are conducted to evaluate the performance of the proposed control protocol and the UDBA algorithm.The results show that,in comparison to the conventional DBA algorithm,the UDBA algorithm can utilize upstream bandwidth more efficiently to reduce packet delay and loss,without adversely impacting downstream transmission performance.
基金Project supported by Shandong Provincial Natural Science Foundation(Grant No.ZR2023LLZ003)the National Natural Science Foundation of China(Grant No.62005145)Fundamental Research Fund of Shandong University,and Shandong Provincial Postdoctoral Science Foundation(Grant No.SDBX202302002)。
文摘We demonstrate an integrating sphere to cool~(87)Rb atoms and measure the recoil-induced resonance and electromagnetically induced absorption spectrum.We measure the relationship between their linewidth and light shift with variation of the detuning and power of the cooling laser and study the performance of the diffuse laser cooling mechanism by the absorption linewidth radio?ν_E/?ν_R and light shift|?_R-?_E|using nonlinear spectroscopy.Specifically,when?ν_E/?ν_R reaches a value of 1.57,the temperature and number of cold atoms achieve the optimal cooling effect.This characterization of absorption linewidth and light shift will provide a method to estimate whether diffuse light cooling achieves the best cooling effect,contributing to the future development of isotropic laser cooling for application in quantum sensing.
基金supported by the National Natural Science Foundation of China(62205180)the Natural Science Foundation of Shandong Province(ZR2022QF029)the Taishan Scholar Program of Shandong Province(Young Scientist).
文摘Semiconductor colloidal quantum wells(CQWs)with atomic-precision layer thickness are rapidly gaining attention for next-generation optoelectronic applications due to their tunable optical and electronic properties.In this study,we investigate the dielectric and optical characteristics of CdSe CQWs with monolayer numbers ranging from 2 to 7,synthesized via thermal injection and atomic layer(c-ALD)deposition techniques.Through a combination of spectroscopic ellipsometry(SE)and first-principles calculations,we demonstrate the significant tunability of the bandgap,refractive index,and extinction coefficient,driven by quantum confinement effects.Our results show a decrease in bandgap from 3.1 to 2.0 eV as the layer thickness increases.Furthermore,by employing a detailed analysis of the absorption spectra,accounting for exciton localization and asymmetric broadening,we precisely capture the relationship between monolayer number and exciton binding energy.These findings offer crucial insights for optimizing CdSe CQWs in optoelectronic device design by leveraging their layer-dependent properties.
文摘It is a pleasure to contribute a commentary on the very interesting review by Dr.Orcioli-Silva and colleagues1 on the simultaneous measurements of cerebral cortex and muscle tissue oxygenation during exercise in healthy adults using near-infrared spectroscopy(NIRS).The first NIRS measurements of the cerebral cortex and muscle were performed on humans in 19772 and 1982,3 respectively.
基金supported by the College Students’ Innovation and Entrepreneurship Training Program (grant Nos.202410649025 and S202410649206)the Sichuan Science and Technology Program (grant No.2025Z NSFSC0315)+1 种基金the Key Laboratory of Detection and Application of Space Effect in Southwest Sichuan at Leshan Normal University,Education Department of Sichuan Province (grant No.ZDXM202401002)supported by National Astronomical Observatories,Chinese Academy of Sciences
文摘This study presents a detailed photometric and spectroscopic analysis of the W UMa-type binary NR Cam,using data from the Transiting Exoplanet Survey Satellite(TESS)and ground-based observations.The light curves exhibit significant variable,with a negative correlation between the brightness of the two maxima—a characteristic of W UMa-type binaries typically attributed to magnetic activity.To explain this behavior,we incorporated a starspot model into our Wilson–Devinney analysis.Our results confirm that NR Cam is a W-subtype,moderately contact binary with a low mass ratio of q=5.75(±0.03)and a fill-out factor of f=33.4(±3.1)%.We also analyzed the orbital period variation using all available times of minima.The resulting O−C diagram reveals a long-term decreasing trend in the orbital period at a rate of dP/dt=−5.18(±0.02)×10^(-8) day yr^(-1),superimposed with a periodic oscillation characterized by an amplitude of A_(3)=0.0019(±0.0001)day and an oscillation period of P_(3)=7.776(±0.003)yr.The long-term decrease is likely due to mass transfer between the binary components,with an estimated mass transfer rate of dM_(2)/dt=1.33(±0.01)×10^(-8)M_(⊙)yr^(-1).The periodic oscillations are likely driven by the light-travel time effect caused by a tertiary companion,with a minimum mass of M_(3)=0.0956(1)M_(⊙)and a maximum separation of 3.841(6)au.Additionally,we considered the possibility that the periodic variation could result from changes in the gravitational quadrupole moment due to magnetic activity cycles,as described by the Applegate mechanism.Our findings confirm that NR Cam is an active binary system,where magnetic activity plays a significant role in its orbital evolution.These results contribute to our understanding of the magnetic dynamics and evolutionary processes in contact binary systems.
基金supported by the National Natural Science Foundation of China(Nos.62175076,62105028,62475085)the Natural Science Foundation of Hubei Province of China(Nos.2024AFA016,2024AFB612)the Open Project Program of Hubei Optical Fundamental Research Center.
文摘The integrated waveguide polarizer is essential for photonic integrated circuits,and various designs of waveguide polarizers have been developed.As the demand for dense photonic integration increases rapidly,new strategies to minimize the device size are needed.In this paper,we have inversely designed an integrated transverse electric pass(TE-pass)polarizer with a footprint of 2.88μm×2.88μm,which is the smallest footprint ever achieved.A direct binary search algorithm is used to inversely design the device for maximizing the transverse electric(TE)transmission while minimizing transverse magnetic(TM)transmission.Finally,the inverse-designed device provides an average insertion loss of 0.99 dB and an average extinction ratio of 33 dB over a wavelength range of 100 nm.
基金support from the National Natural Science Foundation of China(Grant Nos.82060626,22164022,22374153)Talents of Guizhou Science and Technology Cooperation Platform([2020]4104)+2 种基金Science and Technology Innovation Team of Higher Education of Guizhou Provincial Education Department(Qianjiaoji[2023]073)Future Science and Technology Elite Talent Cultivation Project of Zunyi Medical University(ZYSE-2021-01)Zunyi Science and Technology Plan Project(Zunshi Keren Platform[2023]2).
文摘Atherosclerosis(AS),a chronic vascular lesion,constitutes the primary pathological basis for a variety of cardiovascular diseases that account for 85%of total cardiovascular mortality.The accurate identification of AS is of critical significance for early clinical diagnosis and therapeutic interventions for associated diseases.Herein,we report a changeableπ-conjugated probe(ASOCl-1)capable of specific AS imaging with resistance to serum protein interference and microenvironmental perturbations.ASOCl-1 itself was non-conjugated and non-fluorescent.Upon the activation by inflammatory biomarker hypochlorite(OCl^(−)),the probe underwent a molecular rearrangement to generate a near-infrared fluorophore oxazine,with environmental-insusceptible response and anti-interference from serum protein.ASOCl-1 has been used to image OCl^(−)inside foam cells,a type of cell derived from macrophages at the AS sites.Most importantly,ASOCl-1 could achieve in vivo,ex vivo and slice imaging of AS mice.The satisfactory imaging performance and anti-interference capability of ASOCl-1 make it a potential tool for AS imaging diagnosis and disease progression monitoring.
文摘This paper mainly focuses on the influence of colloidal silica polishing on the damage performance of fused silica optics. In this paper, nanometer sized colloidal silica and micron sized ceria are used to polish fused silica optics. The colloidal silica polished samples and ceria polished samples exhibit that the root-mean-squared （RMS） average surface roughness values are 0.7 nm and 1.0 rim, respectively. The subsurface defects and damage performance of the polished optics are analyzed and discussed. It is revealed that colloidal silica polishing will introduce much fewer absorptive con- taminant elements and subsurface damages especially no trailing indentation fracture. The 355-nm laser damage test reveals that each of the fused silica samples polished with colloidal silica has a much higher damage threshold and lower damage density than ceria polished samples. Colloidal silica polishing is potential in manufacturing high power laser optics.
文摘Laser-induced damage in fused silica optics greatly restricts the performances of laser facilities. Gray haze damage,which is always initiated on ceria polished optics, is one of the most important damage morphologies in fused silica optics.In this paper, the laser-induced gray haze damages of four fused silica samples polished with CeO2, Al2O3, ZrO2, and colloidal silica slurries are investigated. Four samples all present gray haze damages with much different damage densities.Then, the polishing-induced contaminant and subsurface damages in four samples are analyzed. The results reveal that the gray haze damages could be initiated on the samples without Ce contaminant and are inclined to show a tight correlation with the shallow subsurface damages.
基金supported by grants from the National Science Foundation of Shandong Province(no.ZR2020ZD35)the Young Talent Cultivation Program of the State Key Laboratory of Crystal Materials,Shandong University
文摘Due to ever-increasing concerns about safety issues in using Li ionic batteries,solid electrolytes have extensively explored.The Li-rich antiperovskite Li_(3)OBr has been considered as a promising solid electrolyte candidate,but it still suffers challenges to achieve a high ionic conductivity owing to the high intrinsic symmetry of the crystal lattice.Herein,we presented a design strategy that introduces various point defects and grain boundaries to break the high lattice symmetry of Li_(3)OBr crystal,and their effect and microscopic mechanism of promoting the migration of Li-ion were explored theoretically.It has been found that Li_(i)are the dominant defects responsible for the fast Li-ion diffusion in bulk Li_(3)OBr and its surface,but they are easily trapped by the grain boundaries,leading to the annihilating of the Frenkel defect pair V'_(Li)+Li_(i),and thus limits the V'_(Li)diffusion at the grain boundaries.The V_(Br)defect near the grain boundaries can effectively drive V'_(Li)across the grain boundary,thereby converting the carrier of Li^(+)migration from Li,in the bulk and surface to V'_(Li)at the grain boundary,and thus improving the ionic conductivity in the whole Li_(3)OBr crystal.This work provides a comprehensive insight into the Li^(+)transport and conduction mechanism in the Li_(3)OBr electrolyte.It opens a new way of improving the conductivity for all-solid-state Li electrolyte material through the defect design.
基金supported by the Joint Research Fund in Astronomy(grant No.U1631108)under a cooperative agreement between the National Natural Science Foundation of China(NSFC)the Chinese Academy of Sciences(CAS)the Chinese National Natural Science Foundation of China(NSFC,grant No.12103030)。
文摘V0405 Dra is a W UMa-type binary star.Based on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the system.The orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by an amplitude of A_(3)=0.0032 day and a period of P_(3)=1.413 years.The orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2013 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact binary.The fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum loss.With further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries.
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The Vietnam National Foundation for Science and Technology Development(NAFOSTED)and the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(Grant No.NRF-2022R1A2C1012996)。
文摘Environmental pollution,such as water contamination,is a critical issue that must be absolutely addressed.Here,three different morphologies of tungsten-based photocatalysts(WO_(3)nanorods,WO_(3)/WS_(2)nanobricks,WO_(3)/WS_(2)nanorods)are made using a simple hydrothermal method by changing the solvents(H_(2)O,DMF,aqueous HCl solution).The as-prepared nanocatalysts have excellent thermal stability,large porosity,and high hydrophilicity.The results show all materials have good photocatalytic activity in aqueous media,with WO_(3)/WS_(2)nanorods(NRs)having the best activity in the photodegradation of bisphenol A(BPA)under visible-light irradiation.This may originate from increased migration of charge carriers and effective prevention of electron–hole recombination in WO_(3)/WS_(2)NRs,whereby this photocatalyst is able to generate more reactive·OH and·O_(2)^(–)species,leading to greater photocatalytic activity.About 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO_(3)/WS_(2)NRs and 5.0 mg/L BPA at pH 7.0.Additionally,the optimal conditions(pH,catalyst dosage,initial BPA concentration)for WO_(3)/WS_(2)NRs are also elaborately investigated.These rod-like heterostructures are expressed as potential catalysts with excellent photostability,efficient reusability,and highly active effectivity in different types of water.In particular,the removal efficiency of BPA by WO_(3)/WS_(2)NRs reduces by only 1.5% after five recycling runs and even reaches 89.1%in contaminated lake water.This study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources,which is advantageous to various applications in environmental remediation.
文摘In thiswork,the perovskite LaZnO_(3) was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole(SMZ)antibiotics under visible light activation.SMZ was almost completely degraded(99.2%±0.3%)within 4 hr by photocatalyst LaZnO_(3) at the optimal dosage of 1.1 g/L,with amineralization proportion of 58.7%±0.4%.The efficient performance of LaZnO_(3) can be attributed to itswide-range light absorption and the appropriate energy band edge levels,which facilitate the formation of active agents such as·O_(2)^(−),h^(+),and·OH.The integration of RP-HPLC/Q-TOF-MS and DFT-based computational techniques revealed three degradation pathways of SMZ,which were initiated by the deamination reaction at the aniline ring,the breakdown of the sulfonamidemoieties,and a process known as Smile-type rearrangement and SO2 intrusion.Corresponding toxicity of SMZ and the intermediateswere analyzed by quantitative structure activity relationship(QSAR),indicating the effectiveness of LaZnO_(3)-based photocatalysis in preventing secondary pollution of the intermediates to the ecosystem during the degradation process.The visible-light-activated photocatalyst LaZnO_(3) exhibited efficient performance in the occurrence of inorganic anions and maintained high durability across multiple recycling tests,making it a promising candidate for practical antibiotic treatment.
基金supported by the DST-SERB,New Delhi,India (EMR/000228/2017)TEQIP-Ⅲ,Ministry of Education,Government of India。
文摘Cubic phase Tm^(3+)/Yb^(3+):Y_(2)O_(3) and Tm^(3+)/Yb^(3+)/Gd^(3+):Y_(2)O_(3) phosphors were prepared by low temperature combustion technique for upconversion emission in UV-visible range.The 980 nm excitation has generated UV emission at 314 nm in tridoped phosphor due to the energy transfer from Tm^(3+) to Gd^(3+)ion.Characteristic emission bands from Tm^(3+) are also observed in both the phosphors.Thermally coupled Stark sublevels ^(1)G_(4(a))(476 nm) and ^(1)G_(4(b))(488 nm) of Tm^(3+) ion were utilised for optical thermometry using fluorescent intensity ratio(FIR) method.The result shows that maximum absolute sensitivity in tridoped phosphor is observed to be 1.33 × 10^(-3) K^(-1) at 298 K.Moreover,temperature rise of phosphor at various pump power densities was also measured and it is estimated to achieve 407 K at the pump power density of 38.46 W/cm^(2).
文摘The laser-induced damage threshold(LIDT) of optical coating is a limited factor for development of a high peak power laser. The automatic damage testing facility was built to determine the LIDT of optics at 1 064 nm and 355 nm.. The cleanning and processing procedure of the substrate and coating technique were improved, and the damage resistance of high-reflective coating at 1 064 nm was increased.
基金supported by JSPS,MEXT,CORE(Center for Optical Research and Education,Utsunomiya University),ASHULA,ILE/Osaka University,and CDI(Cre-ative Department for Innovation,Utsunomiya University).
文摘In this review paper on heavy ion inertial fusion(HIF),the state-of-the-art scientific results are presented and discussed on the HIF physics,including physics of the heavy ion beam(HIB)transport in a fusion reactor,the HIBs-ion illumination on a direct-drive fuel target,the fuel target physics,the uniformity of the HIF target implosion,the smoothing mechanisms of the target implosion non-uniformity and the robust target implosion.The HIB has remarkable preferable features to release the fusion energy in inertial fusion:in particle accelerators HIBs are generated with a high driver efficiency of~30%-40%,and the HIB ions deposit their energy inside of materials.Therefore,a requirement for the fusion target energy gain is relatively low,that would be~50-70 to operate a HIF fusion reactor with the standard energy output of 1 GWof electricity.The HIF reactor operation frequency would be~10-15 Hz or so.Several-MJ HIBs illuminate a fusion fuel target,and the fuel target is imploded to about a thousand times of the solid density.Then the DT fuel is ignited and burned.The HIB ion deposition range is defined by the HIB ions stopping length,which would be~1 mm or so depending on the material.Therefore,a relatively large density-scale length appears in the fuel target material.One of the critical issues in inertial fusion would be a spherically uniform target compression,which would be degraded by a non-uniform implosion.The implosion non-uniformity would be introduced by the Rayleigh-Taylor(R-T)instability,and the large densitygradient-scale length helps to reduce the R-T growth rate.On the other hand,the large scale length of the HIB ions stopping range suggests that the temperature at the energy deposition layer in a HIF target does not reach a very-high temperature:normally about 300 eV or so is realized in the energy absorption region,and that a direct-drive target would be appropriate in HIF.In addition,the HIB accelerators are operated repetitively and stably.The precise control of the HIB axis manipulation is also realized in the HIF accelerator,and the HIB wobbling motion may give another tool to smooth the HIB illumination non-uniformity.The key issues in HIF physics are also discussed and presented in the paper.
基金Project supported by the National Natural Science Foundation of China(51872165)the Primary Research&Development Plan of Shandong Province(2019JZZY010313)。
文摘Disordered-structure crystals have drawn increasing attention as promising ultrashort laser material hosts owing to their broad linewidth.Herein,a novel disordered Nd:YSr_(3)(PO_(4))_(3)(Nd:YSP)crystal with good quality was successfully grown via the Czochralski pulling technique.The absorption and fluorescence spectra of the Nd:YSP single crystal were recorded at ambient temperature.The maximum absorption cross section for Nd:YSP single crystal is found to be approximately 3.89×10^(-20) cm^(2).The stimulated emission cross section for Nd:YSP crystal at~1060 nm was determined to be 7.64×10^(20) cm^(2) with the full width half maximum value of 22 nm.The fluorescence lifetime of the Nd3+ions in the Nd:YSP crystal is fitted to be 288μs.Diode-pumped continuous-wave laser operation is firstly realized at approximately 1060 nm.The maximum output power value from the Nd:YSP crystal is 714 mW,corresponding to a slope efficiency of-12.8%.The results indicate that the Nd:YSP crystal with a disordered structure may be a promising disordered laser host.
