利用Z-Scan量測硒化鋅微晶玻璃薄膜之非線性光學性質

Abstract

我們利用氟化氪準分子雷射濺鍍由溶膠-凝膠方法備製的硒化鋅玻璃靶材於石英玻璃上，形成硒化鋅微晶玻璃薄膜。由螢光和穿透光譜中能隙的藍位移，顯示量子侷限的效應。由拉曼光譜譜線及空間相關模型估算了同調長度，以描述硒化鋅微晶玻璃薄膜的品質。並用鈦藍寶石脈衝雷射為光源（波長790nm），以Z-Scan的方式量測薄膜的n2值，約為1.92~6.78×10-8(esu)，比ZnSe塊材在光源波長532nm量測的n2約為-4.4×10-11，大了許多，確定量子侷限效應能提高非線性項n2的大小。

ZnSe doped glass thin films were deposited on quartz substrates by KrF pulsed laser deposition form sol-gel targets. The structure of this thin film is semiconductor quantum dots in glass and clearly exhibiting quantum confinement. The property can induce an enhancement of third-order optical nonlinearityχ(3) . The blue shift of the photoluminescence (PL) spectrum shows the effect of quantum confinement. We calculate the coherent length to describe the quality of the thin films from Raman spectra and spatial correlation model. The nonlinear refractive index which were measured by Z-Scan method with Ti: sapphire ultrafast pulse laser (wavelength=790nm) were +1.92×10-8esu to +6.78×10-8esu. This constitutes a significant enhancement over bulk ZnSe.