The infrared emission from an external-cavity-tapered diode laser is frequency doubled in a 5-mm β-BaB2O4 crystal that is placed in a resonant-enhancement cavity. For a coupled diode power of 535 mW, 100 mW of continuous-wave, second-harmonic power is generated at λ=392 nm. The ultraviolet (UV) beam is measured to have a nearly ideal beam-quality parameter, M2≃1, in both meridians even though substantial double refraction is present in the nonlinear crystal. Printing of an array of submicron dots on a phase-change film is demonstrated with this UV beam. Also, by printing on photochemical film we demonstrate that improved film sensitivity is possible when a UV source is used.
© 1999 Optical Society of America
[Optical Society of America ]
Anish K. Goyal, Jayant D. Bhawalkar, Yves Conturie, Paul Gavrilovic, Yalan Mao, Hong Po, and John Guerra, "High beam quality of ultraviolet radiation generated through resonant enhanced frequency doubling of a diode laser," J. Opt. Soc. Am. B 16, 2207-2216 (1999)