Ultra-cold atoms in an optical cavity : two-mode laser locking to the cavity avoiding radiation pressure

• Published in: Applied physics. B, Lasers and optics Vol. 89; no. 2-3; pp. 181 - 186
• Main Authors: BUX, S, KRENZ, G, SLAMA, S, ZIMMERMANN, C, COURTEILLE, Ph. W
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-11-2007
• Subjects: Atomic and molecular physics; Atomic properties and interactions with photons; Coherence; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Holes; Laser spectrometers; Lasers; Magnetic resonance; Mechanical effects of light on atoms, molecules, electrons, and ions; Optical cooling of atoms; trapping; Optics; Photon interactions with atoms; Physics; Pumps; Quantum optics; Radiation pressure; Tuning; Two mode laser; Ultracold atom; Magnetooptical trap; Magnetic traps; Optical resonators; Laser cooling; Rubidium Atoms; Phase locking; Experimental study; Radiation pressure
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-007-2793-5

The combination of ultra-cold atomic clouds with the light fields of optical cavities provides a powerful model system for the development of new types of laser cooling and for studying cooperative phenomena. These experiments critically depend on the precise tuning of an incident pump laser with respect to a cavity resonance. Here, we present a simple and reliable experimental tuning scheme based on a two-mode laser spectrometer. The scheme uses a first laser for probing higher-order transversal modes of the cavity having an intensity minimum near the cavity's optical axis, where the atoms are confined by a magnetic trap. In this way the cavity resonance is observed without exposing the atoms to unwanted radiation pressure. A second laser, which is phase locked to the first and tuned close to a fundamental cavity mode, drives the coherent atom-field dynamics.