Stuttgart 2012 – wissenschaftliches Programm
Q 40.2: Vortrag
Donnerstag, 15. März 2012, 10:45–11:00, V38.01
Milliwatt-level mid-infrared difference frequency generation with a femtosecond dual-signal-wavelength optical parametric oscillator — •Robin Hegenbarth1, Andy Steinmann1, György Tóth2, János Hebling2, and Harald Giessen1 — 14th Physics Institute and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany — 2Department of Experimental Physics, University of Pécs, Pécs, Hungary
We employed a novel method of generating mid-infrared radiation, namely difference frequency generation with the two signal wavelengths of a dual-signal-wavelength femtosecond optical parametric oscillator (OPO). We achieved up to 1.2 mW average power at 13.5 µm and tunability between 11 and 18 µm wavelength, with more than 400 µW average power in several wavelength regions, at femtosecond pulse duration and 42 MHz repetition rate. The OPO was pumped by a mode-locked Yb:KGW laser with 530 fs pulse duration and 7.4 W average power. The OPO employed a 1 mm MgO:PPLN crystal with 31.0 µm poling period and the total intracavity group delay dispersion was equal to zero at 1740 nm wavelength. Thus, two different signal wavelengths with identical group delay were generated that traveled simultaneously in one output beam. One of the signal wavelengths can be tuned between 1582 and 1611 nm, the other one between 1795 and 1809 nm. In order to do difference frequency generation, we focused the signal output beam containing the two different signal wavelengths into a 1 mm long gallium selenide crystal. The difference frequency signal was tuned solely by tuning the OPO signal wavelengths.