New Laser and Non-Linear Optical Materials

Abstract

Abstract : Our research under the contract is to investigate crystalline laser host materials and not the glasses. However, even with crystalline laser host materials where the thermal conductivity is much higher, it is still necessary to use slab geometry for high power operations with high repetition. Given the same geometry, material that has high thermal conductivity and high thermal mechanical strength is definitely preferred. Under this contract, we conducted a serious research on high thermal conducting laser host materials. We find the limitation on how far we can push the material. Unfortunately, it is in total conflict between the need of high thermal conductivity and the capability to host large active lazing elements. Materials with high thermal conductivity are in general very simple structure with low coordination and low atomic number elements with covalent bonding. Good examples high thermal conducting materials include diamond, silicon, SiC, BeO, GaAs, etc. We normally consider sapphire (AI203) the best thermal conducting solid state laser host material for Cr32+ and Ti3+. In reality, it is only a mediocre thermal conductor. In recent work of GaN on sapphire, the poor thermal conductivity of sapphire was sited as the major problem for the performance of high brightness blue LEDs and LDs.