Preparation and Nonlinear Optical Properties of Quantum‐Sized CuCl‐Doped Silica Glass by the Sol–Gel Process

Abstract

The sol–gel process has been applied successfully to the preparation of small‐sized CuCl‐doped silica glass with a significant quantum‐sized effect. Gel synthesized by the hydrolysis of a complex solution of Si(OC2H5)4 and CuCl with an HCl catalyst is heated to 900°C to form fine, cubic CuCl crystals. Above 700°C, absorption peaks observed at ∼370 and ∼380 nm are attributed to the excitation of confined Z1,2 and Z3 excitons, respectively, in the CuCl microcrystals. As the size of the CuCl crystals decreases, exciton energy shifts to the higher‐energy side. The resonant third‐order nonlinear susceptibility at 77 K is 1.1 × 10−8 esu, which originates from the enhancement by the quantum‐sized effect of the exciton.