摘要
水汽分子的3ν强振动吸收带位于935 nm附近,差分吸收激光雷达在这个波段具有高探测灵敏度。不幸这一波段位于Ti:Sapphire激光器增益带宽的边缘和Cr:Alexandrite激光器增益带宽之外,染料激光器有较高的自发荧光成分而使其光谱纯度不高,光参量频率转换器可以用作该波段水汽差分吸收激光雷达的发射机。动态稳定的环形谐振腔中有一对走离补偿的、70.7°切角的KTP非线性晶体。它由种子注入单纵模Nd:YAG激光器的二倍频532 nm光脉冲泵浦,脉冲重复频率10 Hz。通过935 nm分布反馈半导体激光器种子注入和"ramp-hold-fire"方法,主动锁定光参量振荡器谐振腔的腔长。发射机平均输出功率达到4.5 W,脉冲长度6 ns,光(532 nm)-光(935 nm)转换效率大于17%,光频的短程和长程频率稳定性30 MHz(RMS)。光束质量M2大约7.8,光谱纯度可以达到99.9%。它将是空间探测大气水汽廓线遥感器的候选光源之一。
3νvibrational absorption band of water vapor lies in the935nm spectral region.Differential absorption lidar has much higher measurement sensitivity in this region.Unfortunately,this spectral region is already at the edge of the gain bandwidth of Ti:Sapphire lasers and outside gain bandwidth of Cr:Alexandrite laser.Spontaneous fluorescence radiation of tunable dye laser is higher,which makes their spectral purity declinable.So optical parametric frequency convertor can be used as the transmitter for water-vapor differential absorption lidar(DIAL).The dynamically-stable ring resonator contains dual70.7°cut,walk-off-compensated KTP nonlinear crystals,which is pumped with an injection seeded,frequency-doubled532nm Nd:YAG laser with repetition frequency of10Hz pulse.The resonator length of OPO was actively locked by injecting the distributed feedback semiconductor lasers of935nm and using"ramp-hold-fire"technique.The average output power of the transmitter was4.5W,the pulse length was6ns,the conversion efficiency of light(532nm)to light(935nm)was more than17%,and the short-range and long-range frequency stability of light frequency was30MHz(RMS).The beam quality M^2was about7.8,and the spectral purity can reach99.9%.It will be one of the candidate light sources for remote sensing of atmospheric water vapor profiles.
作者
洪光烈
梁新栋
肖春雷
孔伟
舒嵘
ong Guanglie;Liang Xindong;Xiao Chunlei;Kong Wei;Shu Rong(Key Laboratory of Space Active Opto-Electronics Technology,Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2018年第12期113-121,共9页
Infrared and Laser Engineering
基金
国家自然科学基金(61775227)
关键词
差分吸收激光雷达
发射机
光参量频率转换器
KTP晶体
腔长稳定
differential absorption lidar
transmitter
optical parametric frequency convertor
KTP crystal
length-stabilized resonator
