Development of Large Diameter Faraday Rotator Using TGG Ceramic for High-Average-Power Laser System

Abstract

A large diameter Faraday isolator for kW class average laser systems was developed using a 53-mm diameter TGG (Tb3Ga5O12) ceramic. The wavefront distortion of TGG ceramic was 0.1 ~ 0.2λ . The maximum magnetic field provided by a permanent magnet was 1.4 ~ 1.5 T. A 53-mm diameter Faraday isolator was demonstrated using a TGG compensation for thermal induced depolarization. The compensated depolarization Faraday rotator is over 4% at incident laser power of over 900 W. This Faraday rotator is scalable to large apertures for kW class (few 10 J pulse at 100 Hz repetition rate) average- power laser systems.