Laser cooling system for caesium.

Abstract

In this final year project, a laser system was built for cooling 133Cs. We build 2 external

cavity diode lasers (ECDL) at 852nm, serving as the lasers for cooling and repumping of

133Cs. The power from one of the ECDL was ampli ed with a tapered ampli er(TA) in the

master oscillator power ampli er (MOPA) con guration. Both lasers are frequency stabilized

to within 1MHz by two di erent techniques: AC locking using saturated absorption

spectroscopy, and trombone locking using beat signal. Then acousto-optic modulators

(AOM) are used to o set and ne tune the frequency of the various lasers beam required

for the cooling experiment. All electronics that required for stabilizing laser were hand

build, this include current controller, temperature controller, AOM controller, COSY box

driver, PI controller and Log-in ampli er. A compact con guration of Doppler free saturation

spectroscopy(COSY box) use in AC locking was also designed and hand build

by author. The 133Cs cooling system setup and laser stabilization will be discuss in this

thesis.