Nonlinear spectroscopy of cold atoms in a spontaneous-force optical trap

Abstract
Probe-wave amplification and absorption spectra are reported for cesium atoms cooled and confined in a Zeeman-shift spontaneous-force optical trap. Novel spectral features are observed with narrow frequency widths and with single-pass gain of 20% in some cases. Negative radiation pressure is demonstrated as the mechanical consequence of optical gain and is investigated as a possible means for optical implosion of a trapped sample.