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Q: Quantenoptik und Photonik
Q 32: Poster Laserspektroskopie und Laser in der Umweltmesstechnik
Q 32.5: Poster
Thursday, March 25, 2004, 14:00–16:00, Schellingstr. 3
Laser frequency offset locking using a side of filter technique — •Gunnar Ritt1, Giovanni Cennini1, Carsten Geckeler1, Martin Weitz1, and Sebastian Fray2 — 1Physikalisches Institut der Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen — 2Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching
Applications of lasers in the areas of spectroscopy, laser cooling and trapping usually require for a precise control and stabilization of frequencies. We have developed a novel scheme for frequency offset locking that is based on generating the error signal from the amplitude response of a sharp electronic rf bandpass filter. Following standard techniques, a beat signal is generated between the laser to be frequency stabilized and a second laser with known frequency. A frequency dependent error signal is generated from this beat signal by using the amplitude response of an electronic bandpass filter. The steep slope of the error signal near the zero-crossing allows for precise frequency locking by a servo loop, while simultaneously a very broad capture range of several hundreds of MHz is obtained. We have demonstrated the scheme by locking the frequency of two diode lasers to a difference frequency of 6.8 GHz. Moreover, we have generated frequency jumps up to 200 MHz within ms time intervals by electronically varying the frequency of a microwave local oscillator used in the setup. The locking scheme is succesfully being operated in an experiment creating Bose-Einstein condensation in a CO2-laser dipole trap.