Highly efficient second harmonic generation by using four pass quadrature frequency conversion

Abstract

A novel frequency converter architecture of four-pass quadrature frequency conversion scheme was developed aiming to achieve high conversion efficiency. A high conversion efficiency of more than 80% has been achieved in this scheme for frequency doubling of 1064-nm in KTP with a low input fundamental laser intensity of 76 MW/cm2. A second- harmonic output of 486 mJ was obtained with 607 mJ of the input 1064-nm fundamental laser at 10 Hz.