基于复合腔的波长可调谐连续橙红色激光器

Continuous Output Orange-red Laser with Tunable Wavelength Based on Composite Cavity

设计并研制了一种基于复合腔结构的波长可调谐、瓦级连续输出的橙红色激光器.该激光器是由半导体激光侧泵Nd∶GdVO_4晶体产生p-偏振1 062.9nm基频光的谐振腔和使用周期性极化晶体MgO∶PPLN(三个极化周期为29.0μm、29.8μm和30.8μm)的单共振光学参量振荡器组成.在两个谐振腔的重叠区域,利用Ⅱ类临界相位匹配KTP晶体对s-偏振信号光与p-偏振1 062.9nm基频光进行腔内和频.通过对MgO∶PPLN晶体进行三个不同极化周期的调谐和30℃~200℃范围内的温度调谐,在三个波段(613.4~619.2nm@29.0μm、620.2~628.9nm@29.8μm和634.4~649.1nm@30.8μm)获得了波长可调谐的橙红色激光连续输出,并在相应波段(3 980.0~3 758.5nm@29.0μm、3 714.2~3 438.3nm@29.8μm和3 278.0~2 940.2nm@30.8μm)获得了波长可调谐的中红外闲频光的连续输出.在30℃最低调谐温度,通过改变晶体的极化周期,在613.4nm、620.2nm和634.4nm处测得最大连续输出功率分别为1.52 W、2.21 W和3.03 W,对应的三束闲频光最大连续输出功率分别为2.36 W@3 980.0nm、3.17 W@3 714.2nm和4.13 W@3 278.0nm.

An orange-red laser was designed and developed based on a composite cavity structure with tunable wavelength, W-level continuous output.It consisted of a resonant cavity which generated p-polarized 1 062.9 nm fundamental frequency light based on laser diode side pumped Nd∶GdVO4 crystal and a single resonant optical parametric oscillator using a periodically poled crystal MgO∶PPLN with three-poling periods （29.0 μm, 29.8 μm, and 30.8 μm）.In the overlap region of the two resonant cavities, the type-II critical phase-matched crystal KTP was used to bring about inner-cavity sum-frequency generation with the s-polarized signal light and the p-polarized 1 062.9 nm fundamental frequency light.By the tuning of three different polarizations of MgO∶PPLN crystal and the temperature tuning in the range of 30℃-200℃, the wavelength tunable orange-red laser with W-level continuous outputs in three bands（613.4-619.2 nm at 29.0 μm,620.2-628.9 nm at 29.8 μm and 634.4-649.1 nm at 30.8 μm） were obtained.In addition, the wavelength tunable mid-infrared idlers were gained in the corresponding bands（3 980.0-3 758.5 nm at 29.0 μm,3 714.2-3 438.3 nm at 29.8 μm and 3 278.0-2 940.2 nm at 30.8 μm）.By changing the poling periods at 30℃ minimum temperature, the maximum continuous output powers were measured as 1.52 W （at 613.4 nm）, 2.21 W （at 620.2 nm） and 3.03 W （at 634.4 nm）.At the same time, the maximum continuous output powers of the three corresponding idlers were measured as 2.36 W（at 3 980.0 nm）, 3.17 W（at 3 714.2 nm） and 4.13 W（at 3 278.0 nm）, respectively.