Tutorial: Current controllers for optimizing laser cooling on cold atom experiments

TL;DR

This paper presents a tutorial on designing current controllers for laser cooling experiments, demonstrating their effectiveness in magnetic field control and cooling of rubidium atoms, with practical applications in spectroscopy.

Contribution

It introduces a simple, effective current source design based on operational amplifiers for cold atom experiments, including detailed implementation and application guidance.

Findings

Achieved cooling of $^{87}$Rb atoms down to 3 μK.

Demonstrated precise magnetic field control via current sources.

Validated the design through Raman spectroscopy experiments.

Abstract

The design of single chip current source based on a common power operational amplifier is presented and demonstrated for the purpose of controlling applied magnetic fields using bias/shim electromagnets in cold atom experiments. The efficacy of the design is realized via application to red-detuned polarization-gradient cooling of $^{87}$Rb down to 3 $\mu$K. Further, we demonstrate Raman spectroscopy using these devices to apply current and so generate a precise, accurate, and reproducible magnetic field. This work is intended as a short tutorial for new graduate students and postdocs of laser cooling and trapping.