Processing for laser radar range images

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.     

基于法珀标准具的激光稳频方法理论研究

介绍了使用法珀(Fabry-Perot,F-P)标准具作为频率标准的三种稳频方法,并且进行理论分析,分别得出了各种方法的鉴频曲线.通过对鉴频曲线进行比较发现边频锁定技术具有斜率大、信号强、控制范围广的优点,优于另外两种方法,是一种理想的激光稳频技术.     

Incoherent and coherent master oscillator/power stimulated Brillouin beam combination for amplifier system with scattering mirror

In this paper, we studied incoherent and coherent beam combining for the master oscillator/power amplifier （MOPA） system with stimulated Brillouin scattering （SBS） mirror. Optic field intensity distributions in the near and far field are numerically calculated for the two kinds of system. The results show that good beam quality in the far field could be obtained. It provides a theoretical basis for experimental research in the future.     

1047-nm all-solid-state laser based on Nd:LuLF

A compact all-solid-state continuous-wave (CW) laser at 1047 nm is developed based on Nd:LuLF, which is grown through the Czochralski technique. From the laser system, 1.3-W laser can be obtained, which corresponds to the slope efficiencies of 20.1% and 49.5% with respect to the incident and absorbed pump powers, respectively. To the best of our knowledge, this is the highest power level achieved at 1047 nm based on the Nd:LuLF crystal.     

Compact waveguide CO2 laser excited by a RF power supply

The design and performance of radio frequency (RF) excited partial Z-fold waveguide CO2 laser with two channels are exposed. The length of the partial Z-fold channel is 3×460 mm and that of the single channel is 460 mm. The electrodes for the two channels are common and excited by a same RF source. According to our analysis, this kind of structure can greatly improve the laser offset frequency stability. In the experiments, we studied the variation of laser output power with gas pressure for two different channels.The maximum laser output power is about 23 W for the partial Z-fold channel and about 6 W for the single channel.     

射频激励双通道不等长电极波导CO2激光器的外差频率调制研究

报道了采用不等长电极结构的射频激励双通道波导CO₂激光器,通过调节射频电源功率的方法可以调谐双通道输出激光的外差频率,其调谐率约为0.1 MHz/W。在未采取任何稳频措施时,其短期外差频率稳定性可达10-10。还在理论上分析了射频功率调谐外差频率的原理。     

激光测深系统中大动态范围压缩技术的实验研究

分析了分通道、距离选通、光电倍增管变增益、正交偏振等多种技术相结合的方法,用以改善机载激光测深系统中激光回波的动态范围。并研制了相应的变增益部件,开展了水池试验以及海上现场试验。试验结果表明,多种方法相结合的技术可对水底信号的动态范围进行有效压缩,满足机载测深系统对浅海测量的动态范围要求;但正交偏振技术对信号测量压缩的改善效果并不明显。报道了试验过程中出现的光电倍增管后脉冲对水深测量的影响。对动态范围压缩技术进一步研究提供了有价值的参考。     

High-Efficient Nd：YLF Q-Switched Laser Operating at 523.5 nm

An intracavity frequency doubling electro-optically Q-switched Nd： YLF 523.5 nm laser is developed. An appropriate cylindrical lens is employed in the oscillator to optimize the mode size and to improve the stability of the cavity. With an incident pump pulse energy of 58 mJ at a 500 Hz repetition rate, a green pulse energy of 16.8 mJ at 523.5 nm is obtained, corresponding to an optical-optical conversion efficiency of 29%. The pulse width is less than 8 ns, and the beam quality factor is M^2≤ 2.5.     

Single-frequency high-energy Yb-doped pulsed all-fiber laser

A single-frequency pulsed all-fiber laser with a master oscillator power amplifier configuration is presented. While maintaining the properties of single mode, linear polarization, and narrow linewidth, a single-pulse energy of 260 μJ and over 500-W peak power is experimentally demonstrated at 1 kHz by employing tensile strain gradient and pulse-shape control methods. In addition, approximately 55 dB of optical signal to noise ratio is also achieved.     

Polarization-locked VCSEL with PM fiber pigtail for quantum communication

Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser (VCSEL) with polarization maintaining (PM) fiber pigtail is fabricated as a decoy state laser source. The VCSEL is packaged in a standard butterfly box integrated with thermoelectric coder (TEC) and thermistor. The optical pulse width of full-width at half-maximum (FWHM) is smaller than 400 ps with a 100-MHz on/off modulation frequency. The results reveal that modulation range is better than 4. Moreover, the polarization is stable, and the power extinction ratio is larger than 25. The center wavelength is 850 nm, and the SMSR is better than 40 dB.