基于周期极化掺镁铌酸锂晶体的中红外同步抽运皮秒光参量振荡器

Mid-Infrared Synchronously Pumped Picosecond Optical Parametric Oscillator Based on PPMgLN Crystal

采用全光纤主振荡功率放大(MOPA)结构皮秒脉冲激光器作为抽运源,搭建同步抽运光参量振荡器(OPO),实现了中红外波段的皮秒脉冲激光输出。光纤激光器输出脉冲重复频率为52MHz,脉宽约20ps,中心波长1064nm。使用一块长50mm、极化光栅周期为30.5μm的周期极化掺镁铌酸锂(PPMgLN)作为非线性频率转换晶体,采用信号光单谐振腔结构,在抽运功率5.2W时获得了平均功率为0.67 W的闲频光输出,中红外参量转换效率为12.9%,斜率效率达14.5%。通过改变晶体温度的方式实现了输出波长在1.544～1.608μm(信号光)和3.15～3.42μm(闲频光)范围内的调谐。从腔长同步匹配的角度讨论了该OPO系统的输出稳定性。

A picosecond mid-infrared optical parametric oscillator （OPO） synchronously pumped by an Yb-doped fiber laser is reported. The OPO is pumped by an all fiber master oscillator power amplifier （MOPA） centered at 1064 nm picosecond pulses with duration of 20 ps at a repetition rate of 52 MHz. A 50 mm periodically poled MgO-doped LiNbO3 （PPMgLN） with a poled grating period of 30.5μm is used as the nonlinear crystal and a single resonant cavity is adopted. At room temperature, 0. 67 W average idler power is obtained at pump power of 5. 2 W with the conversion efficiency from pump to idler being 12.9% and the slope efficiency being 14.5%. By controlling the temperature of PPMgLN crystal, the wavelength tuning range can cover 1. 544--1. 608 μm （singal） and 3.15～3.43μm （idler）. Additionally, the stability of this OPO system is discussed.