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

TL;DR

This paper introduces a two-mode laser spectrometer technique for precisely tuning an incident laser to an optical cavity in ultra-cold atom experiments, avoiding radiation pressure and enabling better control of atom-light interactions.

Contribution

A simple, reliable experimental scheme using a two-mode laser spectrometer for cavity tuning that prevents radiation pressure on ultra-cold atoms.

Findings

Successful cavity resonance observation without radiation pressure

Enhanced control of atom-field interactions

Improved laser cooling techniques

Abstract

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 one and tuned close to a fundamental cavity mode drives the coherent atom-field dynamics.