A laser system for cooling and trapping of fermionic potassium.

Abstract

In this final year project, a laser system for cooling and trapping of fermionic potassium was realized. Two external cavity diode lasers (ECDLs) at 767 nm with a linewidth of 1 MHz were built for the cooling laser and repumping laser. Tapered amplifiers are used to amplify the power of both lasers in the master oscillator power amplifier (MOPA) configuration. The cooling laser is then frequency-stabilized to an atomic resonance with AC-locking on a saturation spectroscopy signal. The repumping laser is locked with respect to the cooling laser by using trombone locking that rely on the beat signal of both lasers. Acousto-optic modulators (AOMs) are used to shift the frequency of lasers for the various beams needed for the experiment: cooling beam, repumper beam, and imaging beam.

Electronic devices; current and temperature controllers of semiconductor amplifiers, PI controllers, Lock-In amplifier, PD with amplifier, and AOM drivers, were built and characterized for the stabilization of laser system. They are reliable, low cost, and most importantly, they are designed in such a way to meet the requirement of our laser system.

As a next step, the laser beams will be overlapped for cooling and trapping rubidium and fermionic potassium in a two species MOT. Finally, a short overview of our goals towards ultracold molecule is described.