CONTINUOUS-WAVE PARAMETRIC OSCILLATOR PUMPED IN THE ULTRAVIOLET

We demonstrate what is to our knowledge the first continuous-wave opti cal parametric oscillator pumped by an ultraviolet source. An argon-io n laser operating at 364 nm is used to pump the nonlinear material lit hium triborate, which generates tunable radiation in the blue-green an d near-infrared spectral regions. With the cavity stabilized to stay o n a single-frequency mode pair, we measure a threshold of 115 mW and a maximum output power of 103 mW. By use of a noncritical phase-matched , type II geometry, tuning ranges from 502 to 494 nm (signal) and 1.32 to 1.38 mum (idler) are observed.