论文标题
SNP $ _2 $ S $ _6 $：有前途的红外非线性光学晶体，具有强烈的非谐振第二谐波生成和相匹配性
SnP$_2$S$_6$: A Promising Infrared Nonlinear Optical Crystal with Strong Non-Resonant Second Harmonic Generation and Phase-matchability
论文作者
论文摘要
具有宽带可调性的高功率红外激光系统非常重要，因为它们在光谱和自由空间通信中的广泛应用。这些系统分别使用总和/差异频率产生分别需要非线性光学（NLO）晶体进行波长上/向下转换。 NLO晶体需要满足许多竞争标准，包括大型非线性光学敏感性，大激光诱导的损伤阈值（LIDT），宽透明度范围和相匹配性。在这里，我们报告了SNP_2S_6的散装单晶，其较大的非共振SHG系数为D33 = 53 pm/v，在1550nm时为53 pm/v，对于飞秒激光脉冲，大的LIDT为350 gw/cm^2。它的透明度范围还范围为0.54μm至8.5μm（带隙为〜2.3 eV），并且可以是I型和II型相匹配的范围。测量完整的线性和SHG张量以及第一原理计算的预测，它们非常同意。对于基本和SHG光的电子带结构中的近距离双共振条件，可增强非共振SHG响应。因此，SNP2S6是红外激光应用的出色候选者。
High-power infrared laser systems with broadband tunability are of great importance due to their wide range of applications in spectroscopy and free-space communications. These systems require nonlinear optical (NLO) crystals for wavelength up/down conversion using sum/difference frequency generation, respectively. NLO crystals need to satisfy many competing criteria, including large nonlinear optical susceptibility, large laser induced damage threshold (LIDT), wide transparency range and phase-matchability. Here, we report bulk single crystals of SnP_2S_6 with a large non-resonant SHG coefficient of d33= 53 pm/V at 1550nm and a large LIDT of 350 GW/cm^2 for femtosecond laser pulses. It also exhibits a broad transparency range from 0.54 μm to 8.5μm (bandgap of ~2.3 eV) and can be both Type I and Type II phase-matched. The complete linear and SHG tensors are measured as well as predicted by first principles calculations, and they are in excellent agreement. A proximate double-resonance condition in the electronic band structure for both the fundamental and the SHG light is shown to enhance the non-resonant SHG response. Therefore, SnP2S6 is an outstanding candidate for infrared laser applications.
