To address the challenge of achieving stable in-phase coherent optical field in high-power laser arrays,we propose a novel dual Talbot diffraction coupling method that combines the on-chip self-injection effect with a...To address the challenge of achieving stable in-phase coherent optical field in high-power laser arrays,we propose a novel dual Talbot diffraction coupling method that combines the on-chip self-injection effect with a mixed-resonant cavity diode laser array(MDLA).The designed MDLA incorporates two types of resonant cavities and an integrated external fractional Talbot cavity to compensate for in-phase mode phase delays.Numerical simulations demonstrate that the nearfield optical pattern can be self-imaged via self-organized phase-locking,while the far-field optical pattern of in-phase mode can be coherently enhanced and modulated to exhibit a single-lobe pattern successfully.Furthermore,this method could inherently provide strong optical coupling and overcome the limited scalability of the weakly-coupled laser arrays.Ultimately,by leveraging self-organized phase-locking and Talbot-induced mode discrimination,our approach offers a robust platform for realizing high-power coherent laser sources with scalable integration potential.展开更多
Currently,laser-induced structural modifications in optical materials have been an active field of research.In this paper,we reported structural modifications in the bulk of sapphire due to picosecond(ps)laser filamen...Currently,laser-induced structural modifications in optical materials have been an active field of research.In this paper,we reported structural modifications in the bulk of sapphire due to picosecond(ps)laser filamentation and analyzed the ionization dynamics of the filamentation.Numerical simulations uncovered that the high-intensity ps laser pulses generate plasma through multi-photon and avalanche ionizations that leads to the creation of two distinct types of structural changes in the material.The experimental bulk modifications consist of a void like structures surrounded by cracks which are followed by a submicrometer filamentary track.By increasing laser energy,the length of the damage and filamentary track appeared to increase.In addition,the transverse diameter of the damage zone increased due to the electron plasma produced by avalanche ionizations,but no increase in the filamentary zone diameter was observed with increasing laser energy.展开更多
The influence of the picosecond(ps) pulsed burst with a nanosecond scale of temporal separation(50 ns) on filamentary traces in sapphire substrate is investigated. The spatiotemporal evolution of the filamentary plasm...The influence of the picosecond(ps) pulsed burst with a nanosecond scale of temporal separation(50 ns) on filamentary traces in sapphire substrate is investigated. The spatiotemporal evolution of the filamentary plasma string induced by sub-pulses of the burst-mode is revealed according to the analysis of the instantaneous photoluminescence images. Due to the presence of residual plasma, the energy loss of sub-pulse during the balancing of self-focusing effect is reduced, and thus refreshes the plasma via refocusing. The refreshed plasma peak generated by the subsequent subpulse appears at relatively low density positions in the formed filamentary plasma string, which results in more uniform densities and less spatial overlap among the plasma peaks. The continuity and uniformity of the filamentary trace in sapphire are enhanced by the burst-mode. Besides, the burst filamentary propagation can also remain effective when the sub-pulse energy is below the self-focusing threshold. Based on this uniform and precise energy propagation mode, the feasibility of its use for the laser lift-off(LLO) process is verified.展开更多
In this study,to improve the unsatisfactory mechanical properties of polyamide-12 materials formed via selective laser sintering,an independent soaking and rapid cooling device is developed to improve the internal mic...In this study,to improve the unsatisfactory mechanical properties of polyamide-12 materials formed via selective laser sintering,an independent soaking and rapid cooling device is developed to improve the internal microstructural defects of the materials via sintering.The maximum tensile strength of the material after heat treatment is 57.3±0.5 MPa at the optimum temperature.Meanwhile,its elongation at break is 293%-297% and 22%-25% at -80℃ and+80℃,respectively.At+80℃,its fracture strength and elongation at break are 53.5±3.2 MPa and 539%-582%,respectively.After heat treatment,its maximum bearing capacity of the triply periodic minimal surface(TPMS)in the elastic stage increased significantly by 106%-119%.Among them,the d-type TPMS after heat treatment shows the best comprehensive bearing capacity;the maximum bearing capacity in the elastic stage is 7.2 kN,which is accompanied by favorable thermal insulation.At lower-surface temperatures of+80℃ and-80℃,the equivalent thermal conductivities are 0.02975 and 0.01592 W/(m·K),respectively.展开更多
High-precision tissue incision in cardiovascular interventions remains hindered by thermal damage and mechanical trauma from conventional tools.Herein,we present a high-peak-power,all-fiber femtosecond laser system in...High-precision tissue incision in cardiovascular interventions remains hindered by thermal damage and mechanical trauma from conventional tools.Herein,we present a high-peak-power,all-fiber femtosecond laser system integrat-ing gain-managed nonlinear(GMN)amplification and hollow-core photonic bandgap fiber(HC-PBGF)compres-sion.The system delivers direct output pulses with durations of~50 fs and peak powers of>10 MW across a repetition rate range of 0.1-5.6 MHz.Notably,at the lowest repetition rate of 0.1 MHz,the system achieves pulse durations as short as 45 fs with a peak power reaching 14.4 MW,representing the highest peak power ever reported for a fully fiber-integrated femtosecond laser architecture.Experimental evaluations via myocardial incision and atrial septal puncture confirmed exceptional tissue-selective incision performance of the system,with no detectable thermal injury or carbonization observed following the procedure.These results overcome critical limitations of existing minimally invasive cardiac instruments,such as collateral thermal effects and inflexible optical configura-tions.By synergizing GMN spectral control with HC-PBGF dispersion engineering,this compact platform enables sub-100 fs pulse compression within<1 m fibers,resolving key barriers to clinical translation.The technology establishes a transformative pathway for cardiovascular catheter-based interventions,offering unprecedented precision for functional tissue preservation and postoperative recovery.展开更多
In recent years,there has been significant growth in the demand from both domestic and international markets for ceramic 3D printing technology.This surge in interest has led to rapid advancements in research and appl...In recent years,there has been significant growth in the demand from both domestic and international markets for ceramic 3D printing technology.This surge in interest has led to rapid advancements in research and applica-tion.Ceramic 3D printing has been applied successfully in diverse fields,including healthcare,cultural creativity,and architectural decoration.Its appeal lies in eliminating the need for molds during manufacturing,resulting in cost-effectiveness,high production efficiency,and unparalleled freedom in structural design.Compared to traditional ceramic molding processes,various industries have widely embraced the advantages of ceramic 3D printing.The current focus of researchers lies in strategic emerging fields,such as healthcare,aerospace,and elec-tronic communication.Researchers conduct multifaceted research on ceramic 3D printing technology in these areas and are eager to invest in industrial development.This article overviews the latest research and application progress in ceramic 3D printing technology in the fields above.In addition,it analyzes the challenges and tech-nical bottlenecks faced by ceramic 3D printing technology in different domains.Moreover,this study explores the opportunities and demands for further development in materials research and development,equipment man-ufacturing,and application field expansion.By examining these aspects,this study sheds light on the immense potential that ceramic 3D printing holds for future growth and innovation.展开更多
The regeneration of the injured nerve and recovery of its function have brought attention in the medical field. Electrical stimulation(ES) can enhance the cellular biological behavior and has been widely studied in th...The regeneration of the injured nerve and recovery of its function have brought attention in the medical field. Electrical stimulation(ES) can enhance the cellular biological behavior and has been widely studied in the treatment of neurological diseases. Microfluidic technology can provide a cell culture platform with the well-controlled environment. Here a novel microfluidic/microelectrode composite microdevice was developed by embedding the microelectrodes to the microfluidic platform, in which microfluidics provided a controlled cell culture platform, and ES promoted the NSCs proliferation. We performed ES on rat neural stem cells(NSCs) to observe the effect on their growth, differentiation, proliferation, and preliminary explored the ES influence on cells in vitro. The results of immunofluorescence showed that ES had no significant effect on the NSCs specific expression, and the NSCs specific expression reached 98.9%± 0.4% after three days of ES. In addition, ES significantly promoted cell growth and the cell proliferation rate reached 49.41%. To conclude, the microfluidic/microelectrode composite microdevice can play a positive role in the nerve injury repair and fundamental research of neurological diseases.展开更多
The transient dynamics of anisotropic properties of Ga As was systematically studied by polarization-dependent ultrafast time-resolved transient absorption.Our findings revealed that the anisotropy of reflectivity was...The transient dynamics of anisotropic properties of Ga As was systematically studied by polarization-dependent ultrafast time-resolved transient absorption.Our findings revealed that the anisotropy of reflectivity was enhanced in both pump-induced and probe-induced processes,suggesting an extraordinary resonance absorption of photon-phonon coupling(PPC)with intrinsic anisotropic characteristic in carrier relaxation,regardless of the concrete crystallinity and orientation of GaAs sample.The results,delivering in-depth cognition about the polarization-dependent ultrafast carrier dynamics,also proved the paramount importance of interaction between polarized laser and semiconductor.展开更多
Ultrafast laser filamentation results from the interaction of ultrafast laser with Kerr media.During filamentary propagation,the transparent medium is altered by numerous linear and nonlinear effects of ultrashort las...Ultrafast laser filamentation results from the interaction of ultrafast laser with Kerr media.During filamentary propagation,the transparent medium is altered by numerous linear and nonlinear effects of ultrashort laser pulses.Filamentation can cause material modification in solids through laser energy deposition and ionization processes,which creates a new opportunity for ultrafast laser processing of materials when combined with filamentary propagation characteristics,such as intensity champing and long propagation distance.This paper reviews the research on ultrafast laser filamentation in solids for micro-and nano-processing,including the fundamental physics,filamentation characteristics,and applications in solids for ultrafast laser filamentation-induced processing.Additionally highlighted are the difficulties and potential applications for solid-based filamentation-induced processing.展开更多
Hollow-core-fiber(HCF)gas lasers(GLs)have garnered significant interest as a novel approach for generating mid-infrared lasers,owing to their inherent benefits of rich emission wavelength,high beam quality,and high ou...Hollow-core-fiber(HCF)gas lasers(GLs)have garnered significant interest as a novel approach for generating mid-infrared lasers,owing to their inherent benefits of rich emission wavelength,high beam quality,and high output power potential.However,they are mostly achieved by a free-space coupling structure,which has a major drawback of being prone to vibrations and other environmental variations.Here,we devise and implement an all-fiber-structure gas-filled HCF amplified spontaneous emission(ASE)source at 3.1μm based on the reverse tapering and angle-cleaved fusion splicing techniques.By optimizing the C_(2)H_(2) gas pressure,a maximum mid-infrared output power of 6.59 W was obtained,corresponding to a slope efficiency of 19.74%and neardiffraction-limited beam qualities of M_(x)^(2)=1.03 and M_(y)^(2)=1.06.Furthermore,with a similar all-fiber configuration,a CO_(2)-filled HCF ASE source at 4.3μm with output power exceeding 1.4 W was generated.To the best of our knowledge,the proposed all-fiber-structure HCF gas light source demonstrates the longest wavelength and highest power reported to date.The development of mid-infrared HCF gas light sources in an all-fiber configuration represents a significant step toward miniaturized HCF lasers,which hold promise as powerful new tools for application in laser medicine,space communication,and other scientific research.展开更多
The self-mixing interferometry(SMI)technique is an emerging sensing technology in microscale particle classification.However,due to the nature of the SMI effect raised by a microscattering particle,the signal analysis...The self-mixing interferometry(SMI)technique is an emerging sensing technology in microscale particle classification.However,due to the nature of the SMI effect raised by a microscattering particle,the signal analysis suffers from many problems compared with a macro target,such as lower signal-to-noise ratio(SNR),short transit time,and time-varying modulation strength.Therefore,the particle sizing measurement resolution is much lower than the one in typical displacement measurements.To solve these problems,in this paper,first,a theoretical model of the phase variation of a singleparticle SMI signal burst is demonstrated in detail.The relationship between the phase variation and the particle size is investigated,which predicts that phase observation could be another alternative for particle detection.Second,combined with continuous wavelet transform and Hilbert transform,a novel phase-unwrapping algorithm is proposed.This algorithm can implement not only efficient individual burst extraction from the noisy raw signal,but also precise phase calculation for particle sizing.The measurement shows good accuracy over a range from 100 nm to 6μm with our algorithm,proving that our algorithm enables a simple and reliable quantitative particle characteristics retrieval and analysis methodology for microscale particle detection in biomedical or laser manufacturing fields.展开更多
Vortex beams carrying orbital angular momentum have important applications in high dimensional optical information processing,manipulations of tiny particles,super-resolution imaging and so on.Among various optical co...Vortex beams carrying orbital angular momentum have important applications in high dimensional optical information processing,manipulations of tiny particles,super-resolution imaging and so on.Among various optical components,metasurface represents an ideal platform for realizing vortex beams with multiple optical functionalities due to its strong ability in manipulating the phase,polarization and amplitude of light.A metasurface combing the functions of a lens and a vortex beam generator can greatly shrink the size of many optical systems.Here,we alternatively propose a new metasurface design based on the concept of a Fresnel zone plate to generate,focus the vortex beams,and perform on-axis interference between different vortex beams.These functions are experimentally demonstrated through encoding the spiral phase profiles into the odd and even zones of a dielectric metasurface.The proposed vortex beam generation strategy employs the advantages of both the Fresnel zone plate and the metasurface,and may open new routes for high-dimensional optical information processing.展开更多
Zirconia(ZrO_(2))ceramics have potential applications in the field of oral medicine owing to their desirable me-chanical properties,biocompatibility,chemical stability,and aesthetic properties.To realize clinical appl...Zirconia(ZrO_(2))ceramics have potential applications in the field of oral medicine owing to their desirable me-chanical properties,biocompatibility,chemical stability,and aesthetic properties.To realize clinical applications,ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics for all-ceramic dental implants were prepared using vat photopolymerization 3D printing technology,and their process optimization,microstructure,mechanics,tribology,and biological proper-ties were studied.The results indicate that when the sintering temperature and holding time are 1600℃and 3 h,respectively,the density of ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics reaches 98.79%,and its Vickers hardness,compressive strength,flexural strength,and fracture toughness also reach their maximum values.Furthermore,the in vitro sim-ulated oral environment wear tests showed that artificial saliva provides a lubricating effect on ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics and improves wear resistance.The biosafety of ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics was evaluated and ZrO_(2)(3Y)/Al_(2)O_(3)had no obvious cytotoxicity and promoted cell proliferation,growth,and adhesion.In addition,its surface has appropriate roughness and good wettability.In conclusion,ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics prepared by vat photopolymerization are promising biomaterials with broad application prospects in dental restoration.展开更多
基金funded by the Science and Technology Commission Foundation of the Central Military Commission(Grant No.2023-JCJQ-JJ-1008)。
文摘To address the challenge of achieving stable in-phase coherent optical field in high-power laser arrays,we propose a novel dual Talbot diffraction coupling method that combines the on-chip self-injection effect with a mixed-resonant cavity diode laser array(MDLA).The designed MDLA incorporates two types of resonant cavities and an integrated external fractional Talbot cavity to compensate for in-phase mode phase delays.Numerical simulations demonstrate that the nearfield optical pattern can be self-imaged via self-organized phase-locking,while the far-field optical pattern of in-phase mode can be coherently enhanced and modulated to exhibit a single-lobe pattern successfully.Furthermore,this method could inherently provide strong optical coupling and overcome the limited scalability of the weakly-coupled laser arrays.Ultimately,by leveraging self-organized phase-locking and Talbot-induced mode discrimination,our approach offers a robust platform for realizing high-power coherent laser sources with scalable integration potential.
基金National Natural Science Foundation of China(51575013,51275011)National Key R&D Program of China(2018 YFB1107500)
文摘Currently,laser-induced structural modifications in optical materials have been an active field of research.In this paper,we reported structural modifications in the bulk of sapphire due to picosecond(ps)laser filamentation and analyzed the ionization dynamics of the filamentation.Numerical simulations uncovered that the high-intensity ps laser pulses generate plasma through multi-photon and avalanche ionizations that leads to the creation of two distinct types of structural changes in the material.The experimental bulk modifications consist of a void like structures surrounded by cracks which are followed by a submicrometer filamentary track.By increasing laser energy,the length of the damage and filamentary track appeared to increase.In addition,the transverse diameter of the damage zone increased due to the electron plasma produced by avalanche ionizations,but no increase in the filamentary zone diameter was observed with increasing laser energy.
基金Project(51975017) supported by the National Natural Science Foundation of ChinaProject(KZ202110005012) supported by the Scientific Research Project of Beijing Educational Committee+1 种基金ChinaProject(2018YFB1107500) supported by the National Key R&D Program of China。
文摘The influence of the picosecond(ps) pulsed burst with a nanosecond scale of temporal separation(50 ns) on filamentary traces in sapphire substrate is investigated. The spatiotemporal evolution of the filamentary plasma string induced by sub-pulses of the burst-mode is revealed according to the analysis of the instantaneous photoluminescence images. Due to the presence of residual plasma, the energy loss of sub-pulse during the balancing of self-focusing effect is reduced, and thus refreshes the plasma via refocusing. The refreshed plasma peak generated by the subsequent subpulse appears at relatively low density positions in the formed filamentary plasma string, which results in more uniform densities and less spatial overlap among the plasma peaks. The continuity and uniformity of the filamentary trace in sapphire are enhanced by the burst-mode. Besides, the burst filamentary propagation can also remain effective when the sub-pulse energy is below the self-focusing threshold. Based on this uniform and precise energy propagation mode, the feasibility of its use for the laser lift-off(LLO) process is verified.
基金supported by Beijing Nova Program(Grant No.20220484008)Foundation of the National Key Laboratory of Human Factors Engineering(Grant No.HFNKL2023WW09).
文摘In this study,to improve the unsatisfactory mechanical properties of polyamide-12 materials formed via selective laser sintering,an independent soaking and rapid cooling device is developed to improve the internal microstructural defects of the materials via sintering.The maximum tensile strength of the material after heat treatment is 57.3±0.5 MPa at the optimum temperature.Meanwhile,its elongation at break is 293%-297% and 22%-25% at -80℃ and+80℃,respectively.At+80℃,its fracture strength and elongation at break are 53.5±3.2 MPa and 539%-582%,respectively.After heat treatment,its maximum bearing capacity of the triply periodic minimal surface(TPMS)in the elastic stage increased significantly by 106%-119%.Among them,the d-type TPMS after heat treatment shows the best comprehensive bearing capacity;the maximum bearing capacity in the elastic stage is 7.2 kN,which is accompanied by favorable thermal insulation.At lower-surface temperatures of+80℃ and-80℃,the equivalent thermal conductivities are 0.02975 and 0.01592 W/(m·K),respectively.
基金National Natural Science Foundation of China(62035002)Natural Science Foundation of Beijing Municipality(1244050).
文摘High-precision tissue incision in cardiovascular interventions remains hindered by thermal damage and mechanical trauma from conventional tools.Herein,we present a high-peak-power,all-fiber femtosecond laser system integrat-ing gain-managed nonlinear(GMN)amplification and hollow-core photonic bandgap fiber(HC-PBGF)compres-sion.The system delivers direct output pulses with durations of~50 fs and peak powers of>10 MW across a repetition rate range of 0.1-5.6 MHz.Notably,at the lowest repetition rate of 0.1 MHz,the system achieves pulse durations as short as 45 fs with a peak power reaching 14.4 MW,representing the highest peak power ever reported for a fully fiber-integrated femtosecond laser architecture.Experimental evaluations via myocardial incision and atrial septal puncture confirmed exceptional tissue-selective incision performance of the system,with no detectable thermal injury or carbonization observed following the procedure.These results overcome critical limitations of existing minimally invasive cardiac instruments,such as collateral thermal effects and inflexible optical configura-tions.By synergizing GMN spectral control with HC-PBGF dispersion engineering,this compact platform enables sub-100 fs pulse compression within<1 m fibers,resolving key barriers to clinical translation.The technology establishes a transformative pathway for cardiovascular catheter-based interventions,offering unprecedented precision for functional tissue preservation and postoperative recovery.
基金supported by Beijing Nova Program of China(Grant No.20220484008)the General Program of Science and Technology Development Project of the Beijing Municipal Education Commission Fund of China(Grant No.KM202010005003).
文摘In recent years,there has been significant growth in the demand from both domestic and international markets for ceramic 3D printing technology.This surge in interest has led to rapid advancements in research and applica-tion.Ceramic 3D printing has been applied successfully in diverse fields,including healthcare,cultural creativity,and architectural decoration.Its appeal lies in eliminating the need for molds during manufacturing,resulting in cost-effectiveness,high production efficiency,and unparalleled freedom in structural design.Compared to traditional ceramic molding processes,various industries have widely embraced the advantages of ceramic 3D printing.The current focus of researchers lies in strategic emerging fields,such as healthcare,aerospace,and elec-tronic communication.Researchers conduct multifaceted research on ceramic 3D printing technology in these areas and are eager to invest in industrial development.This article overviews the latest research and application progress in ceramic 3D printing technology in the fields above.In addition,it analyzes the challenges and tech-nical bottlenecks faced by ceramic 3D printing technology in different domains.Moreover,this study explores the opportunities and demands for further development in materials research and development,equipment man-ufacturing,and application field expansion.By examining these aspects,this study sheds light on the immense potential that ceramic 3D printing holds for future growth and innovation.
基金financially supported by the Key Scientific and Technological Projects of the Beijing Education Commission (No.KZ201910005009)。
文摘The regeneration of the injured nerve and recovery of its function have brought attention in the medical field. Electrical stimulation(ES) can enhance the cellular biological behavior and has been widely studied in the treatment of neurological diseases. Microfluidic technology can provide a cell culture platform with the well-controlled environment. Here a novel microfluidic/microelectrode composite microdevice was developed by embedding the microelectrodes to the microfluidic platform, in which microfluidics provided a controlled cell culture platform, and ES promoted the NSCs proliferation. We performed ES on rat neural stem cells(NSCs) to observe the effect on their growth, differentiation, proliferation, and preliminary explored the ES influence on cells in vitro. The results of immunofluorescence showed that ES had no significant effect on the NSCs specific expression, and the NSCs specific expression reached 98.9%± 0.4% after three days of ES. In addition, ES significantly promoted cell growth and the cell proliferation rate reached 49.41%. To conclude, the microfluidic/microelectrode composite microdevice can play a positive role in the nerve injury repair and fundamental research of neurological diseases.
基金supported by the National Natural Science Foundation of China(Grant Nos.51875006 and 51705009)。
文摘The transient dynamics of anisotropic properties of Ga As was systematically studied by polarization-dependent ultrafast time-resolved transient absorption.Our findings revealed that the anisotropy of reflectivity was enhanced in both pump-induced and probe-induced processes,suggesting an extraordinary resonance absorption of photon-phonon coupling(PPC)with intrinsic anisotropic characteristic in carrier relaxation,regardless of the concrete crystallinity and orientation of GaAs sample.The results,delivering in-depth cognition about the polarization-dependent ultrafast carrier dynamics,also proved the paramount importance of interaction between polarized laser and semiconductor.
基金supported by the National Natural Science Foundation of China (no.51975017)the National Key R&D Program of China (no.2018YFB1107500)the Scientific Research Project of Beijing Educational Committee (no.KZ202110005012)。
文摘Ultrafast laser filamentation results from the interaction of ultrafast laser with Kerr media.During filamentary propagation,the transparent medium is altered by numerous linear and nonlinear effects of ultrashort laser pulses.Filamentation can cause material modification in solids through laser energy deposition and ionization processes,which creates a new opportunity for ultrafast laser processing of materials when combined with filamentary propagation characteristics,such as intensity champing and long propagation distance.This paper reviews the research on ultrafast laser filamentation in solids for micro-and nano-processing,including the fundamental physics,filamentation characteristics,and applications in solids for ultrafast laser filamentation-induced processing.Additionally highlighted are the difficulties and potential applications for solid-based filamentation-induced processing.
基金National Natural Science Foundation of China(62035002)。
文摘Hollow-core-fiber(HCF)gas lasers(GLs)have garnered significant interest as a novel approach for generating mid-infrared lasers,owing to their inherent benefits of rich emission wavelength,high beam quality,and high output power potential.However,they are mostly achieved by a free-space coupling structure,which has a major drawback of being prone to vibrations and other environmental variations.Here,we devise and implement an all-fiber-structure gas-filled HCF amplified spontaneous emission(ASE)source at 3.1μm based on the reverse tapering and angle-cleaved fusion splicing techniques.By optimizing the C_(2)H_(2) gas pressure,a maximum mid-infrared output power of 6.59 W was obtained,corresponding to a slope efficiency of 19.74%and neardiffraction-limited beam qualities of M_(x)^(2)=1.03 and M_(y)^(2)=1.06.Furthermore,with a similar all-fiber configuration,a CO_(2)-filled HCF ASE source at 4.3μm with output power exceeding 1.4 W was generated.To the best of our knowledge,the proposed all-fiber-structure HCF gas light source demonstrates the longest wavelength and highest power reported to date.The development of mid-infrared HCF gas light sources in an all-fiber configuration represents a significant step toward miniaturized HCF lasers,which hold promise as powerful new tools for application in laser medicine,space communication,and other scientific research.
基金supported by the National Natural Science Foundation of China(Nos.61905005 and 52175375)the General Program of Science and Technology Development Project of Beijing Municipal Education Commission(No.KM202110005004)。
文摘The self-mixing interferometry(SMI)technique is an emerging sensing technology in microscale particle classification.However,due to the nature of the SMI effect raised by a microscattering particle,the signal analysis suffers from many problems compared with a macro target,such as lower signal-to-noise ratio(SNR),short transit time,and time-varying modulation strength.Therefore,the particle sizing measurement resolution is much lower than the one in typical displacement measurements.To solve these problems,in this paper,first,a theoretical model of the phase variation of a singleparticle SMI signal burst is demonstrated in detail.The relationship between the phase variation and the particle size is investigated,which predicts that phase observation could be another alternative for particle detection.Second,combined with continuous wavelet transform and Hilbert transform,a novel phase-unwrapping algorithm is proposed.This algorithm can implement not only efficient individual burst extraction from the noisy raw signal,but also precise phase calculation for particle sizing.The measurement shows good accuracy over a range from 100 nm to 6μm with our algorithm,proving that our algorithm enables a simple and reliable quantitative particle characteristics retrieval and analysis methodology for microscale particle detection in biomedical or laser manufacturing fields.
基金supported by the National Natural Science Foundation of China(91950114,11774145)China Postdoctoral Science Foundation(No.2020 M680271)+3 种基金Guangdong Provincial Innovation and Entrepreneurship Project(2017ZT07C071)Natural Science Foundation of Shenzhen Innovation Commission(JCYJ20200109140808088)Shenzhen DRC project[2018]1433Beijing Postdoctoral Research Foundation(Q6101013202101).
文摘Vortex beams carrying orbital angular momentum have important applications in high dimensional optical information processing,manipulations of tiny particles,super-resolution imaging and so on.Among various optical components,metasurface represents an ideal platform for realizing vortex beams with multiple optical functionalities due to its strong ability in manipulating the phase,polarization and amplitude of light.A metasurface combing the functions of a lens and a vortex beam generator can greatly shrink the size of many optical systems.Here,we alternatively propose a new metasurface design based on the concept of a Fresnel zone plate to generate,focus the vortex beams,and perform on-axis interference between different vortex beams.These functions are experimentally demonstrated through encoding the spiral phase profiles into the odd and even zones of a dielectric metasurface.The proposed vortex beam generation strategy employs the advantages of both the Fresnel zone plate and the metasurface,and may open new routes for high-dimensional optical information processing.
基金supported by Beijing Municipal Science and Tech-nology Project(Grant No.KM202010005003)General Program of Science and Technology Development Project of the Beijing Municipal Education Commission.
文摘Zirconia(ZrO_(2))ceramics have potential applications in the field of oral medicine owing to their desirable me-chanical properties,biocompatibility,chemical stability,and aesthetic properties.To realize clinical applications,ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics for all-ceramic dental implants were prepared using vat photopolymerization 3D printing technology,and their process optimization,microstructure,mechanics,tribology,and biological proper-ties were studied.The results indicate that when the sintering temperature and holding time are 1600℃and 3 h,respectively,the density of ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics reaches 98.79%,and its Vickers hardness,compressive strength,flexural strength,and fracture toughness also reach their maximum values.Furthermore,the in vitro sim-ulated oral environment wear tests showed that artificial saliva provides a lubricating effect on ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics and improves wear resistance.The biosafety of ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics was evaluated and ZrO_(2)(3Y)/Al_(2)O_(3)had no obvious cytotoxicity and promoted cell proliferation,growth,and adhesion.In addition,its surface has appropriate roughness and good wettability.In conclusion,ZrO_(2)(3Y)/Al_(2)O_(3)bioceramics prepared by vat photopolymerization are promising biomaterials with broad application prospects in dental restoration.
