Comparison of Seed Sources for a High-Power, Picosecond Mid-IR Optical Parametric Amplifier: Optical Parametric Generation Versus Supercontinuum

The usage of coherent radiation in the mid-infrared (mid-IR) wavelength range (2 – 8 μm) covers a wide spectrum of applications in many different fields [1]. To satisfy the demand for a high-power, picosecond mid-IR source, we are developing an optical parametric system tunable between 1.45 and 3.5 μm in wavelength, which is pumped by an in-house built Yb:YAG thin-disk laser, delivering 80 W of average power at 92 kHz pulse repetition rate, 1030 nm wavelength and ∼1.3 ps pulse duration [2,3]. A stable seed of the mid-IR system, which needs to be tunable between 1.45 and 2.06 μm can be provided e.g. by an optical parametric generator (OPG) (Fig. 1a), or a supercontinuum (SC) (Fig. 1b) stemming from the pump pulses. Here we experimentally compare both seed sources themselves and their effects on the following optical parametric amplifier (OPA) based on a pair of 10 mm long, walk-off compensating KTA crystals.