Continuous-wave mode-locked singly resonant optical parametric oscillator synchronously pumped by a laser diode-pumped Nd:YLF laser

The wide bandwidth of the parametric interaction in nonlinear crystals makes the synchronously pumped optical parametric oscillator (OPO) potentially the most widely tunable source of ultrashort pulses. For practical use, a continuous wave (cw) pump source is desirable, so that each pulse in the train is identical. A desirable feature of a practical and reliable system would be the use of laser diode-pumped sources. To get sufficient peak power for cw synchronous pumping of a singly resonant oscillator (SRO) from the present generation of mode-locked diode pumped lasers, somewhat shorter pulses are needed than those typically generated by active mode-locking. Utilizing the techniques of additive-pulse mode-locking and efficient second-harmonic generation in an external resonant enhancement cavity, we have developed an ultrashort pulse cw mode-locked source pumped by a diode laser, with sufficiently high peak power for synchronous pumping of a SRO in an extracavity configuration