250-MHz synchronously pumped optical parametric oscillator at 2.25-2.6 µm and 4.1-4.9 µm.

ABSTRACT

A compact and versatile femtosecond mid-IR source is presented, based on an optical parametric oscillator (OPO) synchronously pumped by a commercial 250-MHz Erfiber laser. The mid-IR spectrum can be tuned in the range 2.25-2.6 µm (signal) and 4.1-4.9 µm (idler), with average power from 20 to 60 mW. At 2.5 µm a minimum pulse duration of 110 fs and a power of 40 mW have been obtained. Active stabilization of the OPO cavity length has been achieved in the whole tuning range.