In current documented studies,it has been observed that wavelength converters utilizing AlGaAsOI waveguides exhibit suboptimal on-chip wavelength conversion efficiency from the C-band to the 2μm band,generally fallin...In current documented studies,it has been observed that wavelength converters utilizing AlGaAsOI waveguides exhibit suboptimal on-chip wavelength conversion efficiency from the C-band to the 2μm band,generally falling below−20.0 dB.To address this issue,we present a novel wavelength conversion device assisted by a waveguide amplifier,incorporating both AlGaAs wavelength converter and erbium-ytterbium co-doped waveguide amplifier,thereby achieving a notable conversion efficiency exceeding 0 dB.The noteworthy enhancement in efficiency can be attributed to the specific dispersion design of the AlGaAs wavelength converter,which enables an upsurge in conversion efficiency to−15.54 dB under 100 mW of pump power.Furthermore,the integration of an erbium-ytterbium co-doped waveguide amplifier facilitates a loss compensation of over 15 dB.Avoiding the use of external optical amplifiers,this device enables efficient and high-bandwidth wavelength conversion,showing promising applications in various fields,such as optical communication,sensing,imaging,and beyond.展开更多
We propose for the first time,to the best of our knowledge,an on-chip integrated few-mode erbium–ytterbium co-doped waveguide amplifier based on an 800 nm thick Si_(3)N_(4)platform,which demonstrates high amplificati...We propose for the first time,to the best of our knowledge,an on-chip integrated few-mode erbium–ytterbium co-doped waveguide amplifier based on an 800 nm thick Si_(3)N_(4)platform,which demonstrates high amplification gains and low differential modal gains(DMGs)simultaneously.An eccentric waveguide structure and a co-propagating pumping scheme are adopted to balance the gain of each mode.A hybrid mode/polarization/wavelengthdivision(de)multiplexer with low insertion loss and crosstalk is used for multiplexing and demultiplexing in two operation wavebands centered at 1550 nm and 980 nm,where the light in these two bands serves as the signal light and pump light of the amplifier,respectively.The results demonstrate that with an input signal power of 0.1 mW,TE_(0)mode pump power of 300 mW,and TE_(1)mode pump power of 500 m W,the three signal modes(TE_(0)∕TM_(0)∕TE_(1))all exhibit amplification gains exceeding 30 dB,while maintaining a DMG of less than 0.1 dB.展开更多
Measuring the characteristics of seawater constituent is in great demand for studies of marine ecosystems and biogeochemistry.However,existing techniques based on remote sensing or in situ samplings present various tr...Measuring the characteristics of seawater constituent is in great demand for studies of marine ecosystems and biogeochemistry.However,existing techniques based on remote sensing or in situ samplings present various tradeoffs with regard to the diversity,synchronism,temporal-spatial resolution,and depth-resolved capacity of their data products.Here,we demonstrate a novel oceanic triple-field-of-view(FOV)high-spectral-resolution lidar(HSRL)with an iterative retrieval approach.This technique provides,for the first time,comprehensive,continuous,and vertical measurements of seawater absorption coefficient,scattering coefficient,and slope of particle size distribution,which are validated by simulations and field experiments.Furthermore,it depicts valuable application potentials in the accuracy improvement of seawater classification and the continuous estimation of depth-resolved particulate organic carbon export.The triple-FOV HSRL with high performance could greatly increase the knowledge of seawater constituents and promote the understanding of marine ecosystems and biogeochemistry.展开更多
The phase summation effect in sum-frequency mixing process is utilized to avoid a nonlinearity obstacle in the power scaling of single-frequency visible or ultraviolet lasers.Two single-frequency fundamental lasers ar...The phase summation effect in sum-frequency mixing process is utilized to avoid a nonlinearity obstacle in the power scaling of single-frequency visible or ultraviolet lasers.Two single-frequency fundamental lasers are spectrally broadened by phase modulation to suppress stimulated Brillouin scattering in fiber amplifier and achieve higher power.After sum-frequency mixing in a nonlinear optical crystal,the upconverted laser returns to single frequency due to phase summation,when the phase modulations on two fundamental lasers have a similar amplitude but opposite sign.The method was experimentally proved in a Raman fiber amplifier-based laser system,which generated a power-scalable sideband-free single-frequency 590 nm laser.The proposal manifests the importance of phase operation in wave-mixing processes for precision laser technology.展开更多
A continuous-wave(CW)single-longitudinal-mode(SLM)Raman laser at 1240 nm with power of up to 20.6 W was demonstrated in a free-running diamond Raman oscillator without any axial-mode selection elements.The SLM operati...A continuous-wave(CW)single-longitudinal-mode(SLM)Raman laser at 1240 nm with power of up to 20.6 W was demonstrated in a free-running diamond Raman oscillator without any axial-mode selection elements.The SLM operation was achieved due to the spatial-hole-burning free nature of Raman gain and was maintained at the highest available pump power by suppressing the parasitic stimulated Brillouin scattering(SBS).A folded-cavity design was employed for reducing the perturbing effect of resonances at the pump frequency.At a pump power of 69 W,the maximum Stokes output reached 20.6 W,corresponding to a 30%optical-to-optical conversion efficiency from 1064to 1240 nm.The result shows that parasitic SBS is the main physical process disturbing the SLM operation of Raman oscillator at higher power.In addition,for the first time,the spectral linewidth of a CW SLM diamond Raman laser was resolved using the long-delayed self-heterodyne interferometric method,which is 105 kHz at 20 W.展开更多
To obtain cold atom samples with temperatures lower than 100 pK in the cold atom physics rack experiment of the Chinese Space Station,we propose to use the momentum filtering method for deep cooling of atoms.This pape...To obtain cold atom samples with temperatures lower than 100 pK in the cold atom physics rack experiment of the Chinese Space Station,we propose to use the momentum filtering method for deep cooling of atoms.This paper introduces the experimental results of the momentum filtering method verified by our ground testing system.In the experiment,we designed a specific experimental sequence of standing-wave light pulses to control the temperature,atomic number,and size of the atomic cloud.The results show that the momentum filter can effectively and conveniently reduce the temperature of the atomic cloud and the energy of Bose–Einstein condensation,and can be flexibly combined with other cooling methods to enhance the cooling effect.This work provides a method for the atomic cooling scheme of the ultra-cold atomic system on the ground and on the space station,and shows a way of deep cooling atoms.展开更多
We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Consider...We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Considering the non-negligible loop delay, we optimize the loop natural frequency. Without error correction coding, a sensitivity of -37 dBm/-35 dBm is achieved, while the bit error rate is below 10-9 at 2.5 Gbaud/5 Gbaud rate.For the QPSK communication system, the bit rate is twice the baud rate. The loop natural frequency is 0.647 Mrad/s, and the minimized steady-state phase-error standard deviation is 3.83°.展开更多
A 1.5 J Nd:LuAG ceramic active mirror laser amplifier with a high beam quality is demonstrated in which a 0.8%(atomic fraction)Nd-doped Nd:LuAG ceramic disk with a diameter of 64 mm and a thickness of 5.5 mm is used a...A 1.5 J Nd:LuAG ceramic active mirror laser amplifier with a high beam quality is demonstrated in which a 0.8%(atomic fraction)Nd-doped Nd:LuAG ceramic disk with a diameter of 64 mm and a thickness of 5.5 mm is used as a laser gain medium.A maximum single-pass small-signal gain of 2.59 is measured when the pump energy is 11.5 J,with an injected seed energy of 0.4 J;a maximum output energy of 1.5 J is obtained at the repetition rate of 10 Hz.A far-field beam spot 1.25 times the diffraction limit(DL)is achieved by using a stimulated Brillouin scattering phase conjugation mirror(SBS-PCM)for wavefront correction.展开更多
A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd dope...A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd doped. When the pump energy was 26.8 J and the input energy was 0.3 J, the output pulse energy reached 5.4 J, and the pulse width of 11.3 ns at a 5 Hz repetition rate was obtained for the two gain modules in three-pass amplification, with corresponding optical-to-optical efficiency of 21.2%. The beam quality was measured as M_x^2=2.48 and M_y^2=2.43 in horizontal and vertical directions, respectively.展开更多
An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ...An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ of 473 nm blue laser pulse energy was achieved by cascade frequency doubling. The second harmonic conversion efficiency was 64.5%, and overall optical-optical efficiency was 4.2%, respectively. The blue laser pulse width was less than 10 ns, and beam quality factor was less than 2.4.展开更多
A diode-pumped master oscillator power amplifier system based on a cryogenic Yb:YAG active-mirror laser has been developed.The performances of the laser amplifier at low temperature and room temperature have been inve...A diode-pumped master oscillator power amplifier system based on a cryogenic Yb:YAG active-mirror laser has been developed.The performances of the laser amplifier at low temperature and room temperature have been investigated theoretically and experimentally.A maximum output energy of 3.05 J with an optical-to-optical efficiency of 14.7% has been achieved by using the master amplifier system.展开更多
One fast simulation method using Markov chains was introduced to simulate angular,energy,and temporal characteristics of pulsed laser beam propagation underwater.Angular dispersion of photons with a different number o...One fast simulation method using Markov chains was introduced to simulate angular,energy,and temporal characteristics of pulsed laser beam propagation underwater.Angular dispersion of photons with a different number of collisions was calculated based on scattering function and the state transition matrix of Markov chains.Temporal distribution and energy on the receiving plane were obtained,respectively,by use of a novel successive layering model and receiving ratio.The validity of this method was verified by comparing it with the Monte Carlo ray tracing(MCRT)method.The simulation results were close to those obtained by MCRT but were less time consuming and had smoother curves.展开更多
A highly efficient laser system output at the H-13 Fraunhofer line of 486.1 nm has been demonstrated. A high pulse energy single-frequency hybrid 1064 nm master oscillator power amplifier was frequency-tripled to achi...A highly efficient laser system output at the H-13 Fraunhofer line of 486.1 nm has been demonstrated. A high pulse energy single-frequency hybrid 1064 nm master oscillator power amplifier was frequency-tripled to achieve 355 nm laser pulses, which acted as the pmnp source of the beta barium borate nanosecond pulse optical para- metric oscillator. With pump energy of 190 mJ, the laser system generated a maximum output of 62 mJ blue laser pulses at 486.1 nm, corresponding to conversion efficiency of 32.6%. The laser spectrum width was measured to be around 0.1 ran, being in conformity with the spectrum width of the solar Fraunhofer line.展开更多
Clouds and aerosols can significantly affect global climate change and the atmospheric environment,and observing them three-dimensionally with high spatial and temporal resolutions is a long-standing issue.Spaceborne ...Clouds and aerosols can significantly affect global climate change and the atmospheric environment,and observing them three-dimensionally with high spatial and temporal resolutions is a long-standing issue.Spaceborne lidars are effective instruments for the vertical detection of clouds and aerosols globally.Numerous Mie scattering lidars were successfully launched and widely used,such as the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP)and Geoscience Laser Altimeter System.However,the retrieval of Mie scattering lidar data is an ill-posed problem that introduces a large uncertainty.The spaceborne Aerosol and Cloud High Spectral Resolution Lidar(ACHSRL)of China is currently under development and scheduled for launch in the near future.The ACHSRL attracted extensive attention,because it can separate Mie and Rayleigh scattering signals and avoid ill-posed retrieval.In this study,we conducted ACHSRL signal simulation and retrieval to explore the potential of the ACHSRL.First,we proposed a simplified scheme for retrieving optical parameters,which reduced the number of equations and intermediate variables of the traditional method and avoided false extrema in the backscatter coefficient retrieval.Additionally,the experiments showed that the backscatter coefficient retrieval was overestimated owing to the influence of the Poisson noise but can be corrected.Second,we examined the feasibility of the strategy of“first retrieving the lidar ratio then retrieving the extinction coefficient”to improve the extinction coefficient retrieval.We found that the retrieval error in the simulated cases can be reduced to less than 1%of the original retrieval error.Furthermore,we discussed the influence of the uncertainty of the iodine filter transmittance on the retrieval of the optical parameters and found that the average relative error was less than 1‰.Finally,we conducted simulation and retrieval based on the atmospheric parameters measured by the CALIOP.Results showed that the relative error in the backscatter and extinction coefficients at night was 12%and 28%for test cases,respectively,which was superior to that in the backscatter and extinction coefficients of the corresponding CALIOP product(i.e.,75%and 82%).This research is significant and useful for the development and application of satellite lidars in the future.展开更多
The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying...The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying the requirements,the nutation radius is less than 1.13μm,the accuracy of the nutation trail is less than 0.04μm,and the detection range is[?5μm,+5μm].The nutation frequency is 160 times spot position jitter frequency and 100 times intensity jitter frequency of incident light.The analysis is of great significance for determining nutation radius and frequency in the tracking system based on fiber nutation.展开更多
A single-resonant low-threshold type-Iβ-Ba_(2)BO_(4)(BBO) optical parametric oscillator (OPO) with tunable output from 410 nm to 630 nm at 5 k Hz repetition rate is reported.By taking the noncollinear phase matching ...A single-resonant low-threshold type-Iβ-Ba_(2)BO_(4)(BBO) optical parametric oscillator (OPO) with tunable output from 410 nm to 630 nm at 5 k Hz repetition rate is reported.By taking the noncollinear phase matching method,low-threshold OPO operation could be obtained compared with the configuration of collinear phase matching,and the maximum optical–optical conversion efficiency of 11.8%was achieved at 500 nm wavelength when 0.4 m J pump pulse energy was applied.When the noncollinearity angle was preset at 1.6°,4.8°,and 6.3°,a continuously tuning output with a total spectral range of 220 nm was successfully obtained by adjusting the phase matching angle of the BBO crystal.展开更多
An injection-seeded single-resonant optical parametric oscillator(SROPO) with single frequency nanosecond pulsed 2.05 μm wavelength output is presented. Based on two potassium titanyl phosphate crystals and pumped ...An injection-seeded single-resonant optical parametric oscillator(SROPO) with single frequency nanosecond pulsed 2.05 μm wavelength output is presented. Based on two potassium titanyl phosphate crystals and pumped by a 1064 nm single frequency laser pulse, injection seeding is performed successfully by using the ramp-hold-fire technique in a ring cavity with a bow-tie configuration. The SROPO provides 2.65 m J single frequency signal pulse output with a 17.6 ns pulse duration at a 20 Hz repetition rate. A near-diffraction-limited beam is achieved with a beam quality factor M^2 of about 1.2. The spectrum linewidth of the signal pulse is around 26.4 MHz,which is almost the Fourier-transform-limited value.展开更多
基金funded by the Key Program of the National Natural Science Foundation of China(Grant No.62035001)the International Partnership Program of Chinese Academy of Sciences(No.18123KYSB20210013)the Shanghai Science and Technology Innovation Action Plan(No.22dz208700).
文摘In current documented studies,it has been observed that wavelength converters utilizing AlGaAsOI waveguides exhibit suboptimal on-chip wavelength conversion efficiency from the C-band to the 2μm band,generally falling below−20.0 dB.To address this issue,we present a novel wavelength conversion device assisted by a waveguide amplifier,incorporating both AlGaAs wavelength converter and erbium-ytterbium co-doped waveguide amplifier,thereby achieving a notable conversion efficiency exceeding 0 dB.The noteworthy enhancement in efficiency can be attributed to the specific dispersion design of the AlGaAs wavelength converter,which enables an upsurge in conversion efficiency to−15.54 dB under 100 mW of pump power.Furthermore,the integration of an erbium-ytterbium co-doped waveguide amplifier facilitates a loss compensation of over 15 dB.Avoiding the use of external optical amplifiers,this device enables efficient and high-bandwidth wavelength conversion,showing promising applications in various fields,such as optical communication,sensing,imaging,and beyond.
基金Key Program of the National Natural Science Foundation of China(62035001)Shanghai Science and Technology Innovation Action Plan(22dz208700)International Partnership Program of Chinese Academy of Sciences(18123KYSB20210013)。
文摘We propose for the first time,to the best of our knowledge,an on-chip integrated few-mode erbium–ytterbium co-doped waveguide amplifier based on an 800 nm thick Si_(3)N_(4)platform,which demonstrates high amplification gains and low differential modal gains(DMGs)simultaneously.An eccentric waveguide structure and a co-propagating pumping scheme are adopted to balance the gain of each mode.A hybrid mode/polarization/wavelengthdivision(de)multiplexer with low insertion loss and crosstalk is used for multiplexing and demultiplexing in two operation wavebands centered at 1550 nm and 980 nm,where the light in these two bands serves as the signal light and pump light of the amplifier,respectively.The results demonstrate that with an input signal power of 0.1 mW,TE_(0)mode pump power of 300 mW,and TE_(1)mode pump power of 500 m W,the three signal modes(TE_(0)∕TM_(0)∕TE_(1))all exhibit amplification gains exceeding 30 dB,while maintaining a DMG of less than 0.1 dB.
基金supported by the National Key Research and Development Program of China(2022YFB3901704)the Excellent Young Scientist Program of Zhejiang Provincial Natural Science Foundation of China(LR19D050001 and LQ23F050011)+5 种基金the Fundamental Research Funds for the Central Universities(2021XZZX019)the National Natural Science Foundation of China(NSFC)(62205289)the Scientific Research Foundation for Talent Introduction of Zhejiang University Ningbo Campus(20201203Z0175 and 20201203Z0177)the Ningbo Natural Science Foundation(2022J153 and 2022J154)the State Key Laboratory of Modern Optical Instrumentation Innovation Programthe Zhejiang University Global Partnership Fund.
文摘Measuring the characteristics of seawater constituent is in great demand for studies of marine ecosystems and biogeochemistry.However,existing techniques based on remote sensing or in situ samplings present various tradeoffs with regard to the diversity,synchronism,temporal-spatial resolution,and depth-resolved capacity of their data products.Here,we demonstrate a novel oceanic triple-field-of-view(FOV)high-spectral-resolution lidar(HSRL)with an iterative retrieval approach.This technique provides,for the first time,comprehensive,continuous,and vertical measurements of seawater absorption coefficient,scattering coefficient,and slope of particle size distribution,which are validated by simulations and field experiments.Furthermore,it depicts valuable application potentials in the accuracy improvement of seawater classification and the continuous estimation of depth-resolved particulate organic carbon export.The triple-FOV HSRL with high performance could greatly increase the knowledge of seawater constituents and promote the understanding of marine ecosystems and biogeochemistry.
基金The work was partly supported by the National Natural Science Foundation of China(No.62075226).
文摘The phase summation effect in sum-frequency mixing process is utilized to avoid a nonlinearity obstacle in the power scaling of single-frequency visible or ultraviolet lasers.Two single-frequency fundamental lasers are spectrally broadened by phase modulation to suppress stimulated Brillouin scattering in fiber amplifier and achieve higher power.After sum-frequency mixing in a nonlinear optical crystal,the upconverted laser returns to single frequency due to phase summation,when the phase modulations on two fundamental lasers have a similar amplitude but opposite sign.The method was experimentally proved in a Raman fiber amplifier-based laser system,which generated a power-scalable sideband-free single-frequency 590 nm laser.The proposal manifests the importance of phase operation in wave-mixing processes for precision laser technology.
基金supported by the National Natural Science Foundation of China(No.62005073)the Program of the State Key Laboratory of Crystal Materials(No.KF2101)+3 种基金the National Key Research and Development Program of China(No.2020YFC2200300)the Program of the State Key Laboratory of Quantum Optics and Quantum Optics Devices(No.KF202207)the Research Funds of Hangzhou Institute for Advanced Study(No.2022ZZ01006)the Hangzhou Agricultural and Social Development initiative Design Project(No.2022ZDSJ0846).
文摘A continuous-wave(CW)single-longitudinal-mode(SLM)Raman laser at 1240 nm with power of up to 20.6 W was demonstrated in a free-running diamond Raman oscillator without any axial-mode selection elements.The SLM operation was achieved due to the spatial-hole-burning free nature of Raman gain and was maintained at the highest available pump power by suppressing the parasitic stimulated Brillouin scattering(SBS).A folded-cavity design was employed for reducing the perturbing effect of resonances at the pump frequency.At a pump power of 69 W,the maximum Stokes output reached 20.6 W,corresponding to a 30%optical-to-optical conversion efficiency from 1064to 1240 nm.The result shows that parasitic SBS is the main physical process disturbing the SLM operation of Raman oscillator at higher power.In addition,for the first time,the spectral linewidth of a CW SLM diamond Raman laser was resolved using the long-delayed self-heterodyne interferometric method,which is 105 kHz at 20 W.
基金supported by the National Natural Science Foundation of China(Nos.11920101004 and 11934002)the National Key Research and Development Program of China(Nos.2021YFA1400900 and 2021YFA0718300).
文摘To obtain cold atom samples with temperatures lower than 100 pK in the cold atom physics rack experiment of the Chinese Space Station,we propose to use the momentum filtering method for deep cooling of atoms.This paper introduces the experimental results of the momentum filtering method verified by our ground testing system.In the experiment,we designed a specific experimental sequence of standing-wave light pulses to control the temperature,atomic number,and size of the atomic cloud.The results show that the momentum filter can effectively and conveniently reduce the temperature of the atomic cloud and the energy of Bose–Einstein condensation,and can be flexibly combined with other cooling methods to enhance the cooling effect.This work provides a method for the atomic cooling scheme of the ultra-cold atomic system on the ground and on the space station,and shows a way of deep cooling atoms.
文摘We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Considering the non-negligible loop delay, we optimize the loop natural frequency. Without error correction coding, a sensitivity of -37 dBm/-35 dBm is achieved, while the bit error rate is below 10-9 at 2.5 Gbaud/5 Gbaud rate.For the QPSK communication system, the bit rate is twice the baud rate. The loop natural frequency is 0.647 Mrad/s, and the minimized steady-state phase-error standard deviation is 3.83°.
文摘A 1.5 J Nd:LuAG ceramic active mirror laser amplifier with a high beam quality is demonstrated in which a 0.8%(atomic fraction)Nd-doped Nd:LuAG ceramic disk with a diameter of 64 mm and a thickness of 5.5 mm is used as a laser gain medium.A maximum single-pass small-signal gain of 2.59 is measured when the pump energy is 11.5 J,with an injected seed energy of 0.4 J;a maximum output energy of 1.5 J is obtained at the repetition rate of 10 Hz.A far-field beam spot 1.25 times the diffraction limit(DL)is achieved by using a stimulated Brillouin scattering phase conjugation mirror(SBS-PCM)for wavefront correction.
文摘A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd doped. When the pump energy was 26.8 J and the input energy was 0.3 J, the output pulse energy reached 5.4 J, and the pulse width of 11.3 ns at a 5 Hz repetition rate was obtained for the two gain modules in three-pass amplification, with corresponding optical-to-optical efficiency of 21.2%. The beam quality was measured as M_x^2=2.48 and M_y^2=2.43 in horizontal and vertical directions, respectively.
基金supported by the National Key Research and Development Program of China(No.2016YFC1400902)
文摘An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ of 473 nm blue laser pulse energy was achieved by cascade frequency doubling. The second harmonic conversion efficiency was 64.5%, and overall optical-optical efficiency was 4.2%, respectively. The blue laser pulse width was less than 10 ns, and beam quality factor was less than 2.4.
基金the support of the Knowledge Innovation Project of the Chinese Academy of Sciencesthe National Natural Science Foundation of China(No.61008020)
文摘A diode-pumped master oscillator power amplifier system based on a cryogenic Yb:YAG active-mirror laser has been developed.The performances of the laser amplifier at low temperature and room temperature have been investigated theoretically and experimentally.A maximum output energy of 3.05 J with an optical-to-optical efficiency of 14.7% has been achieved by using the master amplifier system.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA22000000)the Ministry of Science and Technology of China (No. 2014AA093301)+1 种基金the Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology (No. 2017B04)the Natural Science Foundation of Shanghai (No. 19YF1453600)
文摘One fast simulation method using Markov chains was introduced to simulate angular,energy,and temporal characteristics of pulsed laser beam propagation underwater.Angular dispersion of photons with a different number of collisions was calculated based on scattering function and the state transition matrix of Markov chains.Temporal distribution and energy on the receiving plane were obtained,respectively,by use of a novel successive layering model and receiving ratio.The validity of this method was verified by comparing it with the Monte Carlo ray tracing(MCRT)method.The simulation results were close to those obtained by MCRT but were less time consuming and had smoother curves.
基金supported by the National Key Research and Development Program of China(No.2016YFC1400902)the National Key Scientific Instrument and Equipment Development Project(No.2013YQ120343)+1 种基金the Scientific Innovation Fund of Chinese Academy of Sciences(No.CXJJ-16S014)the Development Program of China(No.2014AA093301)
文摘A highly efficient laser system output at the H-13 Fraunhofer line of 486.1 nm has been demonstrated. A high pulse energy single-frequency hybrid 1064 nm master oscillator power amplifier was frequency-tripled to achieve 355 nm laser pulses, which acted as the pmnp source of the beta barium borate nanosecond pulse optical para- metric oscillator. With pump energy of 190 mJ, the laser system generated a maximum output of 62 mJ blue laser pulses at 486.1 nm, corresponding to conversion efficiency of 32.6%. The laser spectrum width was measured to be around 0.1 ran, being in conformity with the spectrum width of the solar Fraunhofer line.
基金supported by the National Natural Science Foundation of China(Grant Nos.41627804&41971285)the Natural Science Foundation of Hubei Province(Grant No.2020CFA003)the Fundamental Research Funds for the Central Universities(Grant No.2042020kf0216)。
文摘Clouds and aerosols can significantly affect global climate change and the atmospheric environment,and observing them three-dimensionally with high spatial and temporal resolutions is a long-standing issue.Spaceborne lidars are effective instruments for the vertical detection of clouds and aerosols globally.Numerous Mie scattering lidars were successfully launched and widely used,such as the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP)and Geoscience Laser Altimeter System.However,the retrieval of Mie scattering lidar data is an ill-posed problem that introduces a large uncertainty.The spaceborne Aerosol and Cloud High Spectral Resolution Lidar(ACHSRL)of China is currently under development and scheduled for launch in the near future.The ACHSRL attracted extensive attention,because it can separate Mie and Rayleigh scattering signals and avoid ill-posed retrieval.In this study,we conducted ACHSRL signal simulation and retrieval to explore the potential of the ACHSRL.First,we proposed a simplified scheme for retrieving optical parameters,which reduced the number of equations and intermediate variables of the traditional method and avoided false extrema in the backscatter coefficient retrieval.Additionally,the experiments showed that the backscatter coefficient retrieval was overestimated owing to the influence of the Poisson noise but can be corrected.Second,we examined the feasibility of the strategy of“first retrieving the lidar ratio then retrieving the extinction coefficient”to improve the extinction coefficient retrieval.We found that the retrieval error in the simulated cases can be reduced to less than 1%of the original retrieval error.Furthermore,we discussed the influence of the uncertainty of the iodine filter transmittance on the retrieval of the optical parameters and found that the average relative error was less than 1‰.Finally,we conducted simulation and retrieval based on the atmospheric parameters measured by the CALIOP.Results showed that the relative error in the backscatter and extinction coefficients at night was 12%and 28%for test cases,respectively,which was superior to that in the backscatter and extinction coefficients of the corresponding CALIOP product(i.e.,75%and 82%).This research is significant and useful for the development and application of satellite lidars in the future.
文摘The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying the requirements,the nutation radius is less than 1.13μm,the accuracy of the nutation trail is less than 0.04μm,and the detection range is[?5μm,+5μm].The nutation frequency is 160 times spot position jitter frequency and 100 times intensity jitter frequency of incident light.The analysis is of great significance for determining nutation radius and frequency in the tracking system based on fiber nutation.
基金This work was supported by the Natural Science Foundation of Shanghai(No.19YF1453600)the Key Task Project in Scientific and Technological Research on Social Development of Shanghai(No.20dz1206502)+2 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018SDKJ0102)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22000000)the Major Program of the National Natural Science Foundation of China(No.61991453)。
文摘A single-resonant low-threshold type-Iβ-Ba_(2)BO_(4)(BBO) optical parametric oscillator (OPO) with tunable output from 410 nm to 630 nm at 5 k Hz repetition rate is reported.By taking the noncollinear phase matching method,low-threshold OPO operation could be obtained compared with the configuration of collinear phase matching,and the maximum optical–optical conversion efficiency of 11.8%was achieved at 500 nm wavelength when 0.4 m J pump pulse energy was applied.When the noncollinearity angle was preset at 1.6°,4.8°,and 6.3°,a continuously tuning output with a total spectral range of 220 nm was successfully obtained by adjusting the phase matching angle of the BBO crystal.
基金supported by the National Natural Science Foundation of China(No.61505230)the National Key Research and Development Program of China(No.2016YFC1400902)
文摘An injection-seeded single-resonant optical parametric oscillator(SROPO) with single frequency nanosecond pulsed 2.05 μm wavelength output is presented. Based on two potassium titanyl phosphate crystals and pumped by a 1064 nm single frequency laser pulse, injection seeding is performed successfully by using the ramp-hold-fire technique in a ring cavity with a bow-tie configuration. The SROPO provides 2.65 m J single frequency signal pulse output with a 17.6 ns pulse duration at a 20 Hz repetition rate. A near-diffraction-limited beam is achieved with a beam quality factor M^2 of about 1.2. The spectrum linewidth of the signal pulse is around 26.4 MHz,which is almost the Fourier-transform-limited value.