The Optical Properties of Novel Microchip Laser with Polycrystalline Gain Media, Solid Solutions of Neodymium-Doped YAG and YSAG

Abstract

A novel laser media, Nd:Y₃Sc_xAl_5-xO₁₂ poly-crystals, have been fabricated by the solid-state reaction method under the vacuum sintering. These are the solid-solution composed of Nd³⁺-doped Y₃Al₅O₁₂ (YAG) and Y₃Sc₂Al₃O₁₂ (YSAG), and are the first polycrystalline laser media which are made from 5 kinds of elements, and designable laser media according to compositional parameter x. In this paper we report the dependence of the absorption and emission cross sections of Nd: Y₃Sc_xAl_5-xO₁₂ on x. Using the Judd-Ofelt theory to analyze the optical strength measured in absorption spectra, the parameters of oscillator strengths and fluorescence branch ratios were calculated and found to be the linear dependence on x. The emission studies of Nd: Y₃Sc_xAl_5-xO₁₂revealed the broad emission bandwidth of 5.5 nm around 1.06 mm with x=1. Moreover, we have succeeded in laser oscillation, in which the slope efficiency of 29.6% (the total optical-optical efficiency of 24.7%) was obtained with an uncoated sample.