Efficient 2(nd) and 4(th) harmonic generation of a single-frequency, continuous-wave fiber amplifier.
We demonstrate efficient cavity-enhanced second and fourth harmonic generation of an air-cooled, continuous-wave (cw), single-frequency 1064 nm fiber-amplifier system. The second harmonic generator achieves up to 88% total external conversion efficiency, generating more than 20-W power at 532 nm wavelength in a diffraction-limited beam (M(2) < 1.05). The nonlinear medium is a critically phase-matched, 20-mm long, anti-reflection (AR) coated LBO crystal operated at 25 degrees C. The fourth harmonic generator is based on an AR-coated, Czochralski-grown beta-BaB(2)O(4) (BBO) crystal optimized for low loss and high damage threshold. Up to 12.2 W of 266-nm deep-UV (DUV) output is obtained using a 6-mm long critically phase-matched BBO operated at 40 degrees C. This power level is more than two times higher than previously reported for cw 266-nm generation. The total external conversion efficiency from the fundamental at 1064 nm to the fourth harmonic at 266 nm is >50%.
Laser and Optics Development Department, Core Technology Development Group, Sony Corporation, 6-7-35, Kitashinagawa Shinagawa-ku, Tokyo 141-0001, Japan.
Thomas
T
Sudmeyer
Yutaka
Y
Imai
Hisashi
H
Masuda
Naoya
N
Eguchi
Masaki
M
Saito
Shigeo
S
Kubota
D000669:Amplifiers, Electronic; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008029:Lighting / Q000295:instrumentation*; D014466:Ultraviolet Rays