München 2019 – wissenschaftliches Programm
K 2.1: Vortrag
Dienstag, 19. März 2019, 11:00–11:20, HS 3
Robust difference frequency generation scheme tunable from 6 to 16 µm circumventing spatial beam offset from angular phase-matching — •Florian Mörz1, Tobias Steinle2, Heiko Linnenbank1, Andy Steinmann1, and Harald Giessen1 — 14th Physics Institute, University of Stuttgart, Research Center SCoPE, Pfaffenwaldring 57, 70569 Stuttgart — 2ICFO - The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
As many molecular vibrations are located in the fingerprint region, laser sources covering this wavelength range are of high interest for spectroscopy, due to their high brilliance, beam quality, and low noise. Especially parametric frequency conversion schemes are beneficial, due to their broad tuning range and high conversion efficiencies. Many mid-IR setups are based on difference frequency generation (DFG) between signal and idler beams of optical parametric oscillators (OPOs) or amplifiers (OPAs). However, as the signal and idler wavelengths depend on each other, wavelength tuning requires crystal rotation to satisfy phase-matching. This causes a spatial beam offset, which needs to be compensated accurately. Here, we present a robust DFG scheme, which prevents crystal rotation. The crystal angle is fixed and phase-matching is satisfied by matching the input wavelengths, which can be tuned independently. Thus, a DFG tuning range spanning from 6 to 16 µm with several mW output power, excellent long-term stability and low noise is achieved. Furthermore, we compare the performance of this setup to a signal- and idler-seeded DFG, as well as the performance of AgGaSe2 and GaSe crystals.