红外与激光工程, 2017, 46 (4): 0406004, 网络出版: 2017-06-30
高稳定紧凑型内腔连续光参量振荡器
Highly stable compact intra-cavity continuous-wave optical parametric oscillator
摘要
为了改善内腔连续光参量振荡器(IC-OPO)输出功率不稳定, 弛豫振荡严重等问题, 对IC-OPO进行了改进: (1) 采用热透镜补偿设计, 改善模式匹配; (2) 使用光阑限模, 抑制高阶模振荡; (3) 在腔内加入KTP晶体, 利用二次谐波产生(SHG)过程的非线性损耗抑制弛豫振荡。通过改进, 获得了稳定的紧凑型2.2~4.2 μm的可调谐连续波中红外光源。输出功率波动标准偏差(RMS) 0.52%, 峰值波动范围1.8%, 光束质量因子M2=1.72, 弛豫振荡得到有效抑制。当腔内不加入KTP晶体时, 阈值(808 nm)仅为1.5 W。据笔者所知, 该阈值为国内相关工作报道中的最低值。
Abstract
An Intra-cavity Continuous-Wave Optical Parametric Oscillator(IC-OPO) was developed in order to resolve problems inherent in IC-OPO such as instability of output power, long-lived bursts of relaxation-oscillations, etc. First, compensative design of thermal lens effect was devised to improve pattern matching. Second, an aperture slot was used to suppress the oscillations of high-order transverse mode. Finally, by placing a KTP crystal in the cavity for the purpose of SHG, the relaxation oscillation was suppressed by nonlinear loss. After these improvements, the compact tunable infrared to mid-infrared(2.2-4.2 μm) continuous source with high-stability was obtained. The amplitude stability of output power is 0.52%(RMS) and peak-to-peak amplitude stability is less than ±1.8%. The beam quality M2 is 1.72. Especially, a series of observations show that the relaxation-oscillation is suppressed effectively. Without KTP crystal, the threshold (808 nm) is as low as 1.5 W.
李宇昕, 李世凤, 居盼盼, 赵刚, 吕新杰, 秦亦强. 高稳定紧凑型内腔连续光参量振荡器[J]. 红外与激光工程, 2017, 46(4): 0406004. Li Yuxin, Li Shifeng, Ju Panpan, Zhao Gang, Lv Xinjie, Qin Yiqiang. Highly stable compact intra-cavity continuous-wave optical parametric oscillator[J]. Infrared and Laser Engineering, 2017, 46(4): 0406004.