走离补偿结构的纳秒脉冲光参量振荡器

Nanosecond optical parametric oscillator with walkoff-compensating crystals

采用光参量振荡器(OPO)作为差分吸收(IPDA)雷达发射器实现对大气中CO2浓度的主动探测是目前研究的热点,针对双晶体走离补偿结构的纳秒脉冲KTA光参量振荡器进行了详细的研究。将单频脉冲激光器作为泵浦源,采用环形OPO谐振腔设计,两块临界切割KTA晶体走离补偿放置,实现了脉冲重复频率为100 Hz,脉冲宽度为6.8 ns,单脉冲能量为1.43 mJ的1.57μm激光输出,泵浦光-信号光能量转换效率为13.1%,同时对信号光输出功率、光谱的稳定性进行了测量。为实现双波长OPO运转,提出并测量种子注入接收带宽,为下一步的种子注入实验提供设计依据。实验结果表明:稳定环形腔结构的纳秒OPO能够满足IPDA发射器的需要。

The active measurement of the global carborn cycle was one of the most important topics with Integrated Path Differential Absorption（IPDA） lidar systems. Optical Parametric Oscillators（OPOs） operating at 1.57 Ixm wavelength appear favorable the laser transmitter of IPDA lidar. A nanosecond KTA optical parametric oscillator was sufficiently investigated with walkoff-compensating configuration in a four-mirror ring cavity. With two identical KTA crystals, nanosecond OPO operation was realized by utilizing a single frequency Nd： YAG master oscillator power amplifier （MOPA） laser as pump source. The maximum signal pulse energy of 1.43 mJ and pulse width of 6.8 ns was attained at 100 Hz pulse repetition frequency, the energy conversion efficiency was 13.1%. The output power stability of signal was experimentally measured, as well as the spectrum. For dual-wavelength operation, the seeding acceptable bandwidth was introduced and measured, which provided the basis of the becoming work of injection seeding OPO. Experimentalresults reveal that the nanosecond OPO with ring stable configuration was a promising design to meet the need of IPDA＇s transmitter.