Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 40: Laser Development: Nonlinear Effects

Q 40.2: Vortrag

Mittwoch, 25. März 2015, 11:15–11:30, K/HS2

Difference frequency generation in the mid-IR at 80 MHz high repetition rate using a compact green-pumped soliton optical parametric amplifier — •Florian Mörz, Tobias Steinle, Andy Steinmann, and Harald Giessen — 4th Physics Institute and Research Center Scope, University of Stuttgart

We present a novel approach to generate mid-IR radiation at high repetition rates by using amplified solitons as a seed source for difference frequency generation in GaSe. A 3.4 times higher DFG output power is observed when compared to a non-amplified soliton seed. About 0.35 mW of idler power is generated at 5.4 µm wavelength. The power is currently limited by strong dispersion effects.

The solitons are generated in a tapered fiber and further amplified in a green-pumped OPA. By using a NIR 4 W Yb:CALGO laser source with a pulse width of 80 fs, the often reported soliton instability is negligible. The solitons exhibit a wavelength drift of only 1% over 2 hours. A 10 mm long PPLN crystal is used in the OPA, which is pumped by the frequency-doubled Yb laser and seeded by the solitons. Our system is extremely stable, compact and has a footprint of less than 0.5 m². The OPA gain could be increased about 3 times by applying spectral-focusing for SHG instead of frequency doubling in a standard LBO crystal.

We give an outlook concerning future applications of the MIR DFG system and present further steps to increase the green-pumped OPA gain, to further stabilize the solitons and to compensate for the dispersion effects.