Berlin 2001 – wissenschaftliches Programm

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AMPD: EPS AMPD

AMPD 10: Sitzung 10

AMPD 10.5: Vortrag

Freitag, 6. April 2001, 15:00–15:25, H104

Generation of blue sub-6-fs pulses with quasi-phase-matching — •G. Steinmeyer¹, L. Gallmann¹, U. Keller¹, G. Imeshev², M.M. Fejer², and J.-P. Meyn³ — ¹Inst. of Quantum Electronics, ETH Zürich Hönggerberg HPT, CH-8093 Zürich, Switzerland — ²Ginzton Lab., Stanford University, Stanford, CA 94305, USA — ³FB Physik, Universität Kaiserslautern, D-67663 Kaiserslautern

With the availibility of robust femtosecond pulse sources in the near infrared, there is growing interest in a wavelength conversion of these ultrashort pulses, in particular, into the visible and uv spectral range. Using conventional birefringent phase matching, 8-fs pulses were recently demonstrated by second-harmonic generation of a Ti:sapphire laser [1]. We follow a different approach based on quasi-phase-matching. By electric-field poling in a 300-µm-thick LiTaO₃ substrate, we manufactured an aperiodic grating structure with periods ranging from 1.8 to 6.5 µm. The grating is designed such that a positively chirped Ti:sapphire laser pulse is directly converted into a bandwidth-limited blue pulse, without any need for further dispersion adjustment of the blue light pulses [2]. The pulses have been completely characterized in amplitude and phase with a novel cross-correlation technique. With this first demonstration of quasi-phase-matching in the sub-10-fs range, we readily generated blue pulses of 5.3 fs duration covering a 220-THz bandwidth, which sets a new world record. These pulses are very interesting, e.g. for spectroscopic experiments.
[1] A. Fürbach et al., Appl. Phys. B 70, S37 (2000)
[2] G. Imeshev et al., JOSA B 17 1420 (2000)