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Q: Quantenoptik
Q 10: Poster: Nonlinear Optics
Q 10.8: Poster
Tuesday, April 3, 2001, 12:30–15:00, AT2
Generation of Intense Transform-Limited Narrow-Bandwidth Mid-IR Laser Pulses by Difference Frequency Mixing of Chirped Pulses — •Elmar Schreiber1, Gedeminas Veitas2, and Romas Danielius2 — 1Center for Ultrafast Laser Applications, Princeton University, Princeton, NJ 08544, USA — 2Laser Research Center, Vilnius University, Sauletekio Avenue 9, 2040 Vilnius, Lithuania
The 3 to 5 µm spectral regime certainly attracts many spectroscopists, since it allows direct access to highly selective time-resolved vibrational spectroscopy. To generate intense transform-limited pulses of narrow bandwidth in this wavelength region, we use difference frequency mixing / parametric amplification of stretched pulses. Half of the output power of a titanium-sapphire amplifier (1 kHz, 800 nm, 2 mJ, 1.3 ps) is used to pump a frequency-doubled optical parametric amplifier. The resulting idler pulses seed the difference mixer / amplifier. They are mixed with the residual (∼1 mJ) 800 nm pump pulse in a 15 mm KTA crystal. To obtain narrow-bandwidth pulses, we equally stretch (linear chirp) seed and pump pulses in two seperate grating stretchers wavelength-dependent to 6 to 11 ps duration. The generated pulses have similar pulse duration and are nearly transform-limited. Their spectral bandwidth varies wavelength-dependent between 2 and 3 cm−1 and the pulse energies reach 50 µJ at 3 µm decreasing to ∼10 µm at 5 µm.