As microsatellite technology develops,precise inter-satellite measurement shows its significance in distributed satellite systems.In this Letter,a novel technique is proposed for measuring the inter-satellite distance...As microsatellite technology develops,precise inter-satellite measurement shows its significance in distributed satellite systems.In this Letter,a novel technique is proposed for measuring the inter-satellite distance,which adopts optoelectronic resonance and has a function of self-referencing.Resonance cavities have a high spectral purity and a high oscillation frequency.By utilizing the accumulative amplification principle to convert the measurement of distance to that of the frequency,high accuracy is achieved.In the experiment,this measuring scheme has a large measuring range between 1 and 6 km（can be potentially larger）,and the accuracy is better than 1.5 urn.The relative accuracy reaches the level of 10^-10.展开更多
Imaging laser radar can give intensity and range images,which provide integrated 3-dimensional (3D) information about objects.However, dropouts and range anomalies exacerbate range images, which makes their background...Imaging laser radar can give intensity and range images,which provide integrated 3-dimensional (3D) information about objects.However, dropouts and range anomalies exacerbate range images, which makes their background cluttered and target blurred.For background suppression,a new algorithm that combines intensity image and its mean is presented.By using this algorithm to process actual laser radar range images, most background noises are suppressed.According to range anomalies characteristics,multitemplate selection order mean filtering algorithm is presented and used for actual ladar range images where the distance between two targets is 77 m. This algorithm obtains the clear range image in which the interval of two objects is 75 m.The result shows that the processing algorithm is correct and effective.展开更多
A high-efficiency eye-safe Raman laser was demonstrated by use of the third Stokes radiation in a Ba（NO3）2 crystal pumped by a 1064-nm Nd：YAG laser. The output wavelength of the Raman laser was 1598.5 nm with a ful...A high-efficiency eye-safe Raman laser was demonstrated by use of the third Stokes radiation in a Ba（NO3）2 crystal pumped by a 1064-nm Nd：YAG laser. The output wavelength of the Raman laser was 1598.5 nm with a full-width at half-maximum （FWHM） of 1.5 nm. With an incident pump energy of 140 mJ, a maximum of 18-mJ Raman output energy was generated at a repetition rate of 30 Hz, corresponding to an optical-to-optical conversion efficiency of 12.9%. The Raman pulse duration was shortened to 2.9 ns compared with that of the pump pulse of 19.3 ns. The eye-safe solid-state Raman laser is expected to have wide applications in range-finding, telemetry, laser radar, and other aspects.展开更多
A laser ranging system using all fiber high speed pseudorandom （PN） coded laser at 1550 nm and photon counting is proposed to realize high spatial resolution. Different lengths of PN code are employed in the optical...A laser ranging system using all fiber high speed pseudorandom （PN） coded laser at 1550 nm and photon counting is proposed to realize high spatial resolution. Different lengths of PN code are employed in the optical fiber delay ranging test, the results show the improvement in both ranging accuracy and signal-tonoise ratio （SNR） as PN code trains increase. A ranging accuracy of 3 cm is acquired when transmitting pulses propagate to a target of 1.77 km away and received by an InGaAs/InP avalanche photodiode （APD）. Simulation is also carried out under space borne condition based on current system. The system is demonstrated to have a potential for remote ranging and imaging.展开更多
A Nd:YAG master oscillator power amplifier (MOPA) system, pumped by a pulse flash-lamps as the pump source of optical parametric oscillator (OPO), is employed to improve the pump beam quality of OPO pump source. A bac...A Nd:YAG master oscillator power amplifier (MOPA) system, pumped by a pulse flash-lamps as the pump source of optical parametric oscillator (OPO), is employed to improve the pump beam quality of OPO pump source. A back amplifying configuration with stimulated Brillouin scattering (SBS) phase conjugation mirror is used. OPO pump laser energy of 611 mJ/pulse with 30-ns pulse duration is obtained, and near diffraction limited beam quality is achieved. Based on the type Ⅱ degenerate non-critically phase-matched KTP crystal, the OPO is used to convert pump beam from 1.064 μm to 1.57 μm, eye-safe near infrared laser range source. 1.57-μm output energy of 209 mJ/pulse with 18-ns pulse duration is attained with a short cavity KTP OPO, when pump laser energy is approximately 611 mJ. OPO conversion efficiency is up to 38.7% when pump laser energy is approximately 200 mJ.展开更多
基金supported in part by the Chinese National Natural Science Foundation(Nos.61427817 and61405142)the Independent Innovation Fund of Tianjin University(No.1601)
文摘As microsatellite technology develops,precise inter-satellite measurement shows its significance in distributed satellite systems.In this Letter,a novel technique is proposed for measuring the inter-satellite distance,which adopts optoelectronic resonance and has a function of self-referencing.Resonance cavities have a high spectral purity and a high oscillation frequency.By utilizing the accumulative amplification principle to convert the measurement of distance to that of the frequency,high accuracy is achieved.In the experiment,this measuring scheme has a large measuring range between 1 and 6 km（can be potentially larger）,and the accuracy is better than 1.5 urn.The relative accuracy reaches the level of 10^-10.
文摘Imaging laser radar can give intensity and range images,which provide integrated 3-dimensional (3D) information about objects.However, dropouts and range anomalies exacerbate range images, which makes their background cluttered and target blurred.For background suppression,a new algorithm that combines intensity image and its mean is presented.By using this algorithm to process actual laser radar range images, most background noises are suppressed.According to range anomalies characteristics,multitemplate selection order mean filtering algorithm is presented and used for actual ladar range images where the distance between two targets is 77 m. This algorithm obtains the clear range image in which the interval of two objects is 75 m.The result shows that the processing algorithm is correct and effective.
基金This work was supported by the National High Technology Project (No. 2004AA846020) and the National Natural Science Foundation of China (No. 10334110).
文摘A high-efficiency eye-safe Raman laser was demonstrated by use of the third Stokes radiation in a Ba（NO3）2 crystal pumped by a 1064-nm Nd：YAG laser. The output wavelength of the Raman laser was 1598.5 nm with a full-width at half-maximum （FWHM） of 1.5 nm. With an incident pump energy of 140 mJ, a maximum of 18-mJ Raman output energy was generated at a repetition rate of 30 Hz, corresponding to an optical-to-optical conversion efficiency of 12.9%. The Raman pulse duration was shortened to 2.9 ns compared with that of the pump pulse of 19.3 ns. The eye-safe solid-state Raman laser is expected to have wide applications in range-finding, telemetry, laser radar, and other aspects.
基金the Fund of Chinese Academy of Sciences under Grant No. 61501010304.
文摘A laser ranging system using all fiber high speed pseudorandom （PN） coded laser at 1550 nm and photon counting is proposed to realize high spatial resolution. Different lengths of PN code are employed in the optical fiber delay ranging test, the results show the improvement in both ranging accuracy and signal-tonoise ratio （SNR） as PN code trains increase. A ranging accuracy of 3 cm is acquired when transmitting pulses propagate to a target of 1.77 km away and received by an InGaAs/InP avalanche photodiode （APD）. Simulation is also carried out under space borne condition based on current system. The system is demonstrated to have a potential for remote ranging and imaging.
基金This work was supported by the National Key Laboratory Foundation (No. 51402010301ZS62010), and Harbin Institute of Technology Science Foundation (No. HIT.2001.02).
文摘A Nd:YAG master oscillator power amplifier (MOPA) system, pumped by a pulse flash-lamps as the pump source of optical parametric oscillator (OPO), is employed to improve the pump beam quality of OPO pump source. A back amplifying configuration with stimulated Brillouin scattering (SBS) phase conjugation mirror is used. OPO pump laser energy of 611 mJ/pulse with 30-ns pulse duration is obtained, and near diffraction limited beam quality is achieved. Based on the type Ⅱ degenerate non-critically phase-matched KTP crystal, the OPO is used to convert pump beam from 1.064 μm to 1.57 μm, eye-safe near infrared laser range source. 1.57-μm output energy of 209 mJ/pulse with 18-ns pulse duration is attained with a short cavity KTP OPO, when pump laser energy is approximately 611 mJ. OPO conversion efficiency is up to 38.7% when pump laser energy is approximately 200 mJ.
