Second harmonic generation (SHG) has been observed from zinc sulfide (ZnS) under linearly polarized and circularly polarized femtosecond laser excitations. The output power of SHG signal at 513 nm exhibits a quadratic relationship to the input power of femtosecond laser at 1026 nm, which can figure out the effective SHG response of 2.12 pm/V in ZnS. Additionally, the total, vertical, and horizontal SHG signals all demonstrate well defined cosine-like curves with approximate periods of 40°, indicating a textured crystallized material rather than randomly orientated crystals. Finally, the relative position between the laser focus point and ZnS surface could be detected by the relationship between the SHG power and sample step, due to the regulation of the SHG signal by the power density of incident laser, which is also determined by the relative position. This work may pave the way towards nonlinear optical architectures and femtosecond laser machining.

在线性偏振和圆偏振飞秒激光激发下，已观察到硫化锌（ZnS）产生二次谐波（SHG）。513 nm的SHG信号的输出功率与1026 nm的飞秒激光器的输入功率呈二次关系，这可以得出ZnS中有效的SHG响应为2.12 pm / V。此外，总的，垂直的和水平的SHG信号都显示出定义良好的余弦状曲线，周期约为40°，表明存在纹理化的结晶材料，而不是随机取向的晶体。最后，由于入射激光功率密度对SHG信号的调节，可以通过SHG功率和采样步长之间的关系来检测激光焦点和ZnS表面之间的相对位置，这也由相对位置决定。这项工作可以为非线性光学架构和飞秒激光加工铺平道路。