CONTINUOUS-WAVE TOTAL-INTERNAL-REFLECTION OPTICAL PARAMETRIC OSCILLATOR PUMPED AT 1064 NM

We report what is to our knowledge the first cw 1064-nm-pumped optical parametric oscillator (OPO), using a critically phase-matched (theta(pm) = 45.5-degrees), monolithic total-internal-reflection, doubly resonant OPO fabricated from congruent LiNbO3. Frustrated total-internal-reflection provides variable output coupling for the signal and the idler. The measured finesse of 6000 at 2014 nm implies a round-trip power loss of 0.1%. The low round-trip power losses compensate the 2-degrees Poynting vector walk-off and give a threshold of 130 mW. A passive thermal feedback mechanism causes the OPO to oscillate stably in a single axial-mode pair for more than 30 min. The OPO output tunes in 0.1-nm steps from 2040 to 2225 nm by tuning the pump frequency.