Hannover 2013 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 27: Ultrashort laser pulses: Generation I
Q 27.4: Talk
Tuesday, March 19, 2013, 11:45–12:00, F 342
Broadly tunable femtosecond near- and mid-IR source by direct pumping of an OPA with a 7.4 W Yb:KGW oscillator — Joachim Krauth1, •Tobias Steinle1, Andy Steinmann1, Robin Hegenbarth1, Matteo Conforti2, and Harald Giessen1 — 14th Physics Institute and Research Center SCOPE, University of Stuttgart, Germany — 2CNISM, Dipartimento di Ingegneria dell’Informazione, Università di Brescia, Italy
Tunable mid-infrared laser sources provide access to a versatile field of spectroscopic applications such as near-field and FTIR spectroscopy. In contrast to quantum cascade lasers, parametric light sources based on difference frequency generation, such as optical parametric amplifiers (OPAs) and optical parametric oscillators (OPOs), are able to provide broadly tunable spectra in the near- and mid-IR. We demonstrate a femtosecond OPA that generates more than half a watt of tunable near-IR (1380-1830 nm) and several hundred milliwatts in the mid-IR (2.4-4.2 µm) as well as milliwatt level mid-IR (4.9-9.3 µm) radiation. The OPA is directly pumped by a simple diode-pumped solid-state 7.4 W Yb:KGW oscillator at 41.7 MHz repetition rate, without the need for any amplifier or cavity dumping. We use 5 mm periodically poled lithium niobate (PPLN) and 2 mm GaSe as downconversion crystals and seed this process by a supercontinuum from a tapered fiber. Due to its simplicity and stability, the system is most suitable to replace more complex OPOs as tunable light sources. Simulations predict that using one nonlinear crystal as pre-amplifier to seed a second OPA process leads to even higher output power, conversion efficiency and stability.