RESUMEN
This Letter reports the demonstration of laser cooling without spontaneous emission, and thereby addresses a significant controversy. It works by restricting the atom-light interaction to a time short compared to a cycle of absorption followed by natural decay. It is achieved by using the bichromatic force on an atomic transition with a relatively long excited state lifetime and a relatively short cooling time so that spontaneous emission effects are minimized. The observed width of the one-dimensional velocity distribution is reduced by ×2 thereby reducing the "temperature" by ×4. Moreover, our results comprise a compression in phase space because the spatial expansion of the atomic sample is limited. This accomplishment is of interest to direct laser cooling of molecules or in experiments where working space or time is limited.
RESUMEN
We present a novel interferometric technique for the accurate measurement of acoustic velocity based on an optical phase shifter consisting of a pair of properly aligned acousto-optic modulators (AOMs). Results for the z-axis longitudinal mode velocities in lead molybdate (PbMoO(4)) and tellurium dioxide (TeO(2)) at 80 MHz are reported and compared with earlier results. A longstanding inconsistency in the PbMoO(4) velocity is resolved.