Zoubir Arnaud, Richardson Martin, Rivero Clara, Schulte Alfons, Lopez Cedric, Richardson Kathleen, Hô Nicolas, Vallée Réal
School of Optics and Center for Research and Education in Optics and Lasers, University of Central Florida, Orlando, Florida 32816, USA.
Opt Lett. 2004 Apr 1;29(7):748-50. doi: 10.1364/ol.29.000748.
Single-channel waveguides and Y couplers were fabricated in chalcogenide thin films by use of femtosecond laser pulses from a 25-MHz repetition rate Ti:sapphire laser. Refractive-index differentials (delta n > 10(-2)) were measured through interferometric microscopy and are higher than the typical values reported for oxide glasses. The dependence of the index differential on the peak intensity reveals the nonlinear nature of the photosensitivity in arsenic trisulfide below its bandgap energy, and the refractive-index change is correlated to the photoinduced structural changes inferred by Raman spectroscopy data. A free-electron model to predict the parametric dependence of delta n is proposed.
利用重复频率为25MHz的钛宝石激光器产生的飞秒激光脉冲，在硫系化合物薄膜中制备了单通道波导和Y型耦合器。通过干涉显微镜测量了折射率差（δn>10^(-2)），该值高于报道的氧化物玻璃的典型值。折射率差对峰值强度的依赖性揭示了三硫化砷在其带隙能量以下光敏性的非线性本质，并且折射率变化与拉曼光谱数据推断的光致结构变化相关。提出了一个自由电子模型来预测δn的参数依赖性。
