泵浦光聚焦特性对高重频1064 nm被动调Q激光器的影响

Influence of Pump Light Focused Characteristics on High Repetition Frequency 1064 nm Passively Q-switched Laser

研究了泵浦光聚焦特性对被动调Q激光器输出激光特性的影响。使用10 W激光二极管(LD)和焦距为4 mm的耦合聚焦镜,在不改变LD和谐振腔结构与间距(15 mm)的情况下,选取5个耦合聚焦镜位置,研究对应泵浦光聚焦特性对输出激光特性的影响,特别是对输出脉冲稳定性的影响。泵浦功率为3.550 W时,相较于其他耦合聚焦镜位置,在耦合聚焦镜距离LD 7.50 mm处,被动调Q激光器实现了更高重复频率(160 kHz)、更高平均输出功率(360 mW)、更高单脉冲能量(2.250μJ)、更低时域抖动(120 ns)的稳定脉冲输出。实验数据说明,耦合聚焦镜距离LD 7.50 mm处,泵浦光聚焦光斑与谐振腔基模光斑的匹配程度较好。理论计算得出,耦合聚焦镜距离LD 7.50 mm时,谐振腔基模光斑尺寸与泵浦光聚焦光斑束腰尺寸的比值为0.854,该比值对今后开展高重频被动调Q激光器相关研究具有一定的借鉴意义。

The effect of pump focusing characteristic on output laser characteristics of passively Q-switched solidstate(PQS)laser is studied.Using a 10 W laser diode(LD)and a coupling focusing lens with focal length of 4 mm,without changing the cavity structure and the distance between LD and resonator(15 mm),five coupling focusing lens positions were selected to research the effect of pump focusing characteristic on output laser characteristics,especially on the stability of the output pulse.When the distance between LD and the coupling focusing lens is 7.50 mm,at a continuous-wave pump power of 3.550 W,a passively Q-switched laser with higher repetition rate(160 kHz),higher average output power(360 mW),higher single-pulse energy(2.250μJ)and lower time jitter(120 ns)was obtained.The experimental results indicate that the match degree between pump focusing spot and fundamental mode spot is good when the distance between LD and the coupling focusing lens is 7.50 mm.The theoretical calculation results indicate that the ratio of the fundamental mode spot size to the focusing spot size is 0.854 when the distance between LD and the coupling focusing lens is 7.50 mm.The ratio can be used as a reference for the research of high repetition-frequency PQS laser.