Fundamental mode, single-frequency laser amplifier for gravitational wave detectors

An amplifier design for efficient amplification of linearly polarized fundamental mode lasers is presented. The concept was verified by amplifying single-frequency input powers from 1 W to 20 W into output power ranges of 35 W up to 65 W. Beam quality measurements with a mode-analyzer cavity showed only minor beam quality degradation due to the amplification process. (c) 2007 Optical Society of America.