Two Step Deceleration of Cesium Atomic Beam by Frequency Modulated Diode Lasers

Toshio Yoneyama, Shunichi Sato

Richard N. Watts

Toru Hirayama, Shunichi Sato

The velocity of a cesium atomic beam was controlled using two broadband frequency-modulated, external-cavity diode lasers. One laser beam was used to decelerate faster atoms and the other was used to accelerate slower atoms. The central velocity of the atoms was readily tuned in a wide range while maintaining the width and peak height of a velocity distribution. In addition, the velocity distribution of cesium atoms was calculated on the basis of the scattering force caused by two frequency-modulated laser beams. The calculated peak ratio was in good agreement with the experimental result.

Takeshi Ikegami, Takayuki Kurosu, Shinichi Ohshima +1 more

Present status of laser cooling experiments in NRLM is presented. Laser cooling and trapping experiments for cesium atoms are continued in NRLM to develop an atomic fountain frequency standard. As a first step, we performed Cs atomic beam deceleration and trapping experiments. Atomic beam cesium atoms were decelerated by counterpropagating radiation from semiconductor laser diodes. The laser frequency was chirped to keep it in resonance with the decelerated atoms. The decelerated atoms were trapped by six mutually orthogonal laser beams in a magneto-optical trap configuration. The atoms could also be trapped directly from ambient cesium gas in a glass cell without using the deceleration laser beam. The characteristics of the trapped atoms are reported.

Yuji Fukaya, Shunichi Sato

A simple control method for the velocity distribution of cesium atoms is demonstrated using a frequency modulated diode laser with a wider spectrum. Current to the diode laser was modulated and the laser spectrum was broadened to overlap the Doppler broadening of the atomic beam. The reduction of the atom velocity was achieved on the basis of the laser cooling technique and a single narrow peak at approximately 45 m/s was observed. From a view point of a novel purification process, the possibility to deflect this cooled cesium atomic beam was discussed to spatially separate the beam from impurities.

Kristen Oldja, Matthew J. Wright