针对可用于微弱红外图像探测的光学参量变频与增强技术,进行了仿真与实验探索.针对高增益光参量放大器(OPA)过程中的参量荧光背景噪声,提出了基于外接圆模型的空间滤波技术,通过仿真优化设计,利用空域、频域滤波与像传递系统相结合的方...针对可用于微弱红外图像探测的光学参量变频与增强技术,进行了仿真与实验探索.针对高增益光参量放大器(OPA)过程中的参量荧光背景噪声,提出了基于外接圆模型的空间滤波技术,通过仿真优化设计,利用空域、频域滤波与像传递系统相结合的方法,将参量荧光背景的抑制比例超过70%,其增强后的成像质量较之前有明显改善,峰值信噪比提升22%.基于10 Hz,355 nm的大能量皮秒紫外抽运激光,实现了红外波段到可见光波段的参量频率上转换,得到了超过1.3×108(82 d B)的光学图像增益.实验结果表明,采用高增益OPA作为光学预放大级之后,常规非制冷电荷耦合器件可实现微弱红外成像的有效探测,灵敏度可达每像素7.4个光子.该方案有望用于单光子级高灵敏红外成像场合.展开更多
The ionization of magnesium vapor by resonant and off-resonant laser irradiation was investigated for the first time.Enhancement of ion signals was observed at the 3s^(2)-3s4d ^(1)D and 3s^(2)-3s5s ^(1)S two-photon at...The ionization of magnesium vapor by resonant and off-resonant laser irradiation was investigated for the first time.Enhancement of ion signals was observed at the 3s^(2)-3s4d ^(1)D and 3s^(2)-3s5s ^(1)S two-photon atomic resonances.A"hybrid resonance"was detected which involves the production of 3s3p-^(1)P atoms from molecular magnesium.Doubly charged ions by laser radiation tuned to one and two-photon resonance levels of Mgll were produced.展开更多
A new experimental phenomenon-resonance dip(weakening)of multiphoton ionization in Mg vapor with 3s,3p ^(1)P as an intermediate state has been observed.Photoionization and coherent radiation at 5183.7Å,accompanie...A new experimental phenomenon-resonance dip(weakening)of multiphoton ionization in Mg vapor with 3s,3p ^(1)P as an intermediate state has been observed.Photoionization and coherent radiation at 5183.7Å,accompanied by ionization dip when Mg vapor pressure was high enough,were studied simultaneously as functions of vapor pressure,laser power density and buffer gas pressure.Possible contributions to ionization dip and coherent radiation are discussed.展开更多
We demonstrate an all-solid quasi-continuous-wave(QCW) narrow-band source tunable to sodium D2 aline at589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal.The...We demonstrate an all-solid quasi-continuous-wave(QCW) narrow-band source tunable to sodium D2 aline at589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal.The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd:YAG master oscillator power amplifier(MOPA) laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M2= 1.25,frequency stability better than ±0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled,and a sodium laser guided star has been successfully observed in the field test.展开更多
Tunable coherent emission is generated in a single-pass,cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate(PPLN).Three ranges of wavelength,including vis...Tunable coherent emission is generated in a single-pass,cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate(PPLN).Three ranges of wavelength,including visible output from 628 nm to 639 nm,near-infrared output from 797 nm to 816 nm,and mid-infrared output from 3167 nm to 3459 nm,were obtained from the monolithic PPLN,which consists of a 10-mm section for 532-nm-pumped optical parametric generation(OPG)and a 7-mm section for 1064-nm-pumped sum frequency generation(SFG).A pump-to-signal conversion efficiency of 23.4%for OPG at 50°C and a quantum efficiency of 26.2%for SFG at 200°C were obtained.展开更多
A diode-end-pumped Q-switched high-efficiency Nd,Cr:YAG laser with simultaneous dual-wavelength emission at 946 nm and 1.3μm is demonstrated.The maximum output power of 1.93 W with simultaneous dual-wavelength operat...A diode-end-pumped Q-switched high-efficiency Nd,Cr:YAG laser with simultaneous dual-wavelength emission at 946 nm and 1.3μm is demonstrated.The maximum output power of 1.93 W with simultaneous dual-wavelength operation is achieved at an absorbed pump power of 13.32 W and an absorbed slope efficiency of 15.15%.The maximum optical-optical efficiency is 14.49% with pulse widths of 16.38 ns at 946 nm and 26.65 ns at 1.3 μm.A maximum total repetition rate of 43.25 kHz is obtained.展开更多
We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off c...We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics,respectively.The highest power is 3.72 mW at 193 nm,and the fluctuation at 2.85 mW in 130 min is less than ±2%.展开更多
A 785 nm diode-side-pumped high-power high-pulse-repetition-frequency Q-switched 2 μm Tm:YAG laser system is reported.Under a pump power of 1300 W,a 171.4 W average output power is achieved at a pulse repetition freq...A 785 nm diode-side-pumped high-power high-pulse-repetition-frequency Q-switched 2 μm Tm:YAG laser system is reported.Under a pump power of 1300 W,a 171.4 W average output power is achieved at a pulse repetition frequency of 10 kHz.To our knowledge,this is the highest average output power for a diode-pumped all solid-state Q-switched 2 μm Tm:YAG laser.The laser output corresponds to an optical-to-optical conversion efficiency of 13.3% and a slope efficiency of 18.9%.展开更多
Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO:LiNbO 3 crystals...Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO:LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 × 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.展开更多
We demonstrate the output characteristic of broadband parametric amplification of incoherent light pulses in a 355-nm pumped degenerate picosecond optical parametric amplification with either saturated or unsaturated ...We demonstrate the output characteristic of broadband parametric amplification of incoherent light pulses in a 355-nm pumped degenerate picosecond optical parametric amplification with either saturated or unsaturated amplification.The optical parametric amplifier is seeded by the fluorescence generated in a solution of pyridine-1 dye in ethanol.With the saturated amplification,we can obtain high energy incoherent light pulses,whose full width at half maximum bandwidth varies from 16 nm to 53 nm for the different phase matching angles near degeneracy.Moreover,the unsaturated bandwidth of the amplified pulses fits well to the calculated result at degeneracy.Selecting s-polarized fluorescence with a Glan-Taylor prism,the maximum bandwidth of the amplified fluorescence is found to be 59 nm for a purely s-polarized seed.The maximum output energy is 0.67 mJ for the optical parametric amplifier.By using an optical filter and compressor,the generated high energy incoherent light has great potential as the incoherent pump,signal or idler wave of a parametric down-conversion process,so that a wave with a high degree of coherence can be generated from an incoherent pump light.展开更多
Tomographic imaging and three-dimensional reconstruction based on a high-gain picosecond optical parametric amplifier (OPA) is demonstrated. More than 40dB intensity amplification of the image is achieved from the hig...Tomographic imaging and three-dimensional reconstruction based on a high-gain picosecond optical parametric amplifier (OPA) is demonstrated. More than 40dB intensity amplification of the image is achieved from the high-gain OPA.The images of various longitudinal positions of the target are extracted by the gated nature of the OPA,then a three-dimensional (3-D) surface topography of the target is reconstructed.The gated and high-gain property of the OPA allows tomographic optical imaging together with 3-D profile reconstruction of the target in turbid media.展开更多
We report on a polarization-adjustable picosecond deep-ultraviolet (DUV) laser at 177.3 nm.The DUV laser was produced by second harmonic generation from a mode-locked laser at 355 nm in nonlinear optical crystal KBBF....We report on a polarization-adjustable picosecond deep-ultraviolet (DUV) laser at 177.3 nm.The DUV laser was produced by second harmonic generation from a mode-locked laser at 355 nm in nonlinear optical crystal KBBF.The laser delivered a maximum average output power of 1.1 m W at 177.3 nm.The polarization of the 177.3nm beam was adjusted with linear and circular polarization by means of λ/4 and λ/2 wave plates.To the best of our knowledge,the laser has been employed as the circularly polarized and linearly polarized DUV light source for a spin- and angle-resolved photoemission spectroscopy with high resolution for the first time.展开更多
We demonstrate a high power high beam quality diode-pumped 1 112-nm Nd:YAG master-oscillator poweramplifier(MOPA)laser system.To increase the extraction efficiency and output power,a four-pass amplifier scheme is empl...We demonstrate a high power high beam quality diode-pumped 1 112-nm Nd:YAG master-oscillator poweramplifier(MOPA)laser system.To increase the extraction efficiency and output power,a four-pass amplifier scheme is employed.Finally,the injected laser output power is amplified from 26 to 64 W with beam quality factor M2=2.85.Furthermore,a theoretical model that takes the temporal overlap inversion number dynamics into account is employed to analyze the performance of the MOPA laser system,and a good agreement with the experimental data is obtained.展开更多
A weak infrared(IR) image amplifier with more than 60-dB optical gain and frequency up-conversion is developed from a picosecond(PS) 355-nm pumped gated optical parametric amplifier(OPA) in a β-BaB2O4(BBO) crystal. T...A weak infrared(IR) image amplifier with more than 60-dB optical gain and frequency up-conversion is developed from a picosecond(PS) 355-nm pumped gated optical parametric amplifier(OPA) in a β-BaB2O4(BBO) crystal. The IR image at 1064 nm is amplified and up-converted into the visible region at 532 nm by parametric amplification and up-conversion. With the optimized optical gain, the lowest detectable energy of the image can be as low as 1.8 femto-Joule per pulse, which is three orders of magnitude lower than the detection limit of a charge-coupled device(CCD) camera. The transversal resolution of the OPA imaging is investigated, and the approaches for higher detection sensitivity and higher transversal resolution are proposed.展开更多
文摘针对可用于微弱红外图像探测的光学参量变频与增强技术,进行了仿真与实验探索.针对高增益光参量放大器(OPA)过程中的参量荧光背景噪声,提出了基于外接圆模型的空间滤波技术,通过仿真优化设计,利用空域、频域滤波与像传递系统相结合的方法,将参量荧光背景的抑制比例超过70%,其增强后的成像质量较之前有明显改善,峰值信噪比提升22%.基于10 Hz,355 nm的大能量皮秒紫外抽运激光,实现了红外波段到可见光波段的参量频率上转换,得到了超过1.3×108(82 d B)的光学图像增益.实验结果表明,采用高增益OPA作为光学预放大级之后,常规非制冷电荷耦合器件可实现微弱红外成像的有效探测,灵敏度可达每像素7.4个光子.该方案有望用于单光子级高灵敏红外成像场合.
文摘The ionization of magnesium vapor by resonant and off-resonant laser irradiation was investigated for the first time.Enhancement of ion signals was observed at the 3s^(2)-3s4d ^(1)D and 3s^(2)-3s5s ^(1)S two-photon atomic resonances.A"hybrid resonance"was detected which involves the production of 3s3p-^(1)P atoms from molecular magnesium.Doubly charged ions by laser radiation tuned to one and two-photon resonance levels of Mgll were produced.
文摘A new experimental phenomenon-resonance dip(weakening)of multiphoton ionization in Mg vapor with 3s,3p ^(1)P as an intermediate state has been observed.Photoionization and coherent radiation at 5183.7Å,accompanied by ionization dip when Mg vapor pressure was high enough,were studied simultaneously as functions of vapor pressure,laser power density and buffer gas pressure.Possible contributions to ionization dip and coherent radiation are discussed.
文摘We demonstrate an all-solid quasi-continuous-wave(QCW) narrow-band source tunable to sodium D2 aline at589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal.The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd:YAG master oscillator power amplifier(MOPA) laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M2= 1.25,frequency stability better than ±0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled,and a sodium laser guided star has been successfully observed in the field test.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB632704)
文摘Tunable coherent emission is generated in a single-pass,cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate(PPLN).Three ranges of wavelength,including visible output from 628 nm to 639 nm,near-infrared output from 797 nm to 816 nm,and mid-infrared output from 3167 nm to 3459 nm,were obtained from the monolithic PPLN,which consists of a 10-mm section for 532-nm-pumped optical parametric generation(OPG)and a 7-mm section for 1064-nm-pumped sum frequency generation(SFG).A pump-to-signal conversion efficiency of 23.4%for OPG at 50°C and a quantum efficiency of 26.2%for SFG at 200°C were obtained.
基金Supported by the National Basic Research Program of China under Grant No 2013CB632704
文摘A diode-end-pumped Q-switched high-efficiency Nd,Cr:YAG laser with simultaneous dual-wavelength emission at 946 nm and 1.3μm is demonstrated.The maximum output power of 1.93 W with simultaneous dual-wavelength operation is achieved at an absorbed pump power of 13.32 W and an absorbed slope efficiency of 15.15%.The maximum optical-optical efficiency is 14.49% with pulse widths of 16.38 ns at 946 nm and 26.65 ns at 1.3 μm.A maximum total repetition rate of 43.25 kHz is obtained.
基金supported by the State Key Program for Basic Research of China (Grant No. 2010CB630706)National High Technology Research and Development Program of Chinathe National Natural Science Foundation of China (Grant No. 61138004)
文摘We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics,respectively.The highest power is 3.72 mW at 193 nm,and the fluctuation at 2.85 mW in 130 min is less than ±2%.
基金Supported by the National High-Technology Research and Development Program of Chinathe National Basic Research Pro-gram of China,the National Natural Science Foundation of Chinathe Knowledge Innovation Program of Chinese Academy of Sciences.
文摘A 785 nm diode-side-pumped high-power high-pulse-repetition-frequency Q-switched 2 μm Tm:YAG laser system is reported.Under a pump power of 1300 W,a 171.4 W average output power is achieved at a pulse repetition frequency of 10 kHz.To our knowledge,this is the highest average output power for a diode-pumped all solid-state Q-switched 2 μm Tm:YAG laser.The laser output corresponds to an optical-to-optical conversion efficiency of 13.3% and a slope efficiency of 18.9%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61078005)the National Basic ResearchProgram of China (Grant No. 2007CB613205)the China Postdoctoral Science Foundation
文摘Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO:LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 × 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.
基金Project supported by the National Basic Research Program of China (Grant No. 2007CB613205)the National Natural Science Foundation of China (Grant No. 61078005)
文摘We demonstrate the output characteristic of broadband parametric amplification of incoherent light pulses in a 355-nm pumped degenerate picosecond optical parametric amplification with either saturated or unsaturated amplification.The optical parametric amplifier is seeded by the fluorescence generated in a solution of pyridine-1 dye in ethanol.With the saturated amplification,we can obtain high energy incoherent light pulses,whose full width at half maximum bandwidth varies from 16 nm to 53 nm for the different phase matching angles near degeneracy.Moreover,the unsaturated bandwidth of the amplified pulses fits well to the calculated result at degeneracy.Selecting s-polarized fluorescence with a Glan-Taylor prism,the maximum bandwidth of the amplified fluorescence is found to be 59 nm for a purely s-polarized seed.The maximum output energy is 0.67 mJ for the optical parametric amplifier.By using an optical filter and compressor,the generated high energy incoherent light has great potential as the incoherent pump,signal or idler wave of a parametric down-conversion process,so that a wave with a high degree of coherence can be generated from an incoherent pump light.
文摘Tomographic imaging and three-dimensional reconstruction based on a high-gain picosecond optical parametric amplifier (OPA) is demonstrated. More than 40dB intensity amplification of the image is achieved from the high-gain OPA.The images of various longitudinal positions of the target are extracted by the gated nature of the OPA,then a three-dimensional (3-D) surface topography of the target is reconstructed.The gated and high-gain property of the OPA allows tomographic optical imaging together with 3-D profile reconstruction of the target in turbid media.
基金Supported by the National Basic Research Program of China under Grant No 2010CB630706the National High-Technology Research and Development Program of Chinathe National Natural Science Foundation of China,and the Knowledge Innovation Program of Chinese Academy of Sciences.
文摘We report on a polarization-adjustable picosecond deep-ultraviolet (DUV) laser at 177.3 nm.The DUV laser was produced by second harmonic generation from a mode-locked laser at 355 nm in nonlinear optical crystal KBBF.The laser delivered a maximum average output power of 1.1 m W at 177.3 nm.The polarization of the 177.3nm beam was adjusted with linear and circular polarization by means of λ/4 and λ/2 wave plates.To the best of our knowledge,the laser has been employed as the circularly polarized and linearly polarized DUV light source for a spin- and angle-resolved photoemission spectroscopy with high resolution for the first time.
基金supported by the State Key Program for Basic Research of China(No.2010CB630706)the National High Technology Research and Development Program of China(No.2011AA30202)the Major Program of the National Natural Science Foundation of China(Nos.51132008 and 61138004)
文摘We demonstrate a high power high beam quality diode-pumped 1 112-nm Nd:YAG master-oscillator poweramplifier(MOPA)laser system.To increase the extraction efficiency and output power,a four-pass amplifier scheme is employed.Finally,the injected laser output power is amplified from 26 to 64 W with beam quality factor M2=2.85.Furthermore,a theoretical model that takes the temporal overlap inversion number dynamics into account is employed to analyze the performance of the MOPA laser system,and a good agreement with the experimental data is obtained.
基金supported by the State Key Program for Basic Research of China(No.2010CB630706)the Knowledge Innovation Program of Chinese Academy of Sciences
文摘A weak infrared(IR) image amplifier with more than 60-dB optical gain and frequency up-conversion is developed from a picosecond(PS) 355-nm pumped gated optical parametric amplifier(OPA) in a β-BaB2O4(BBO) crystal. The IR image at 1064 nm is amplified and up-converted into the visible region at 532 nm by parametric amplification and up-conversion. With the optimized optical gain, the lowest detectable energy of the image can be as low as 1.8 femto-Joule per pulse, which is three orders of magnitude lower than the detection limit of a charge-coupled device(CCD) camera. The transversal resolution of the OPA imaging is investigated, and the approaches for higher detection sensitivity and higher transversal resolution are proposed.
