Microwave sidebands for laser cooling by direct modulation of a tapered amplifier

TL;DR

This paper introduces a simple, efficient method to generate GHz-range sidebands on a laser using a tapered amplifier, enabling effective atom cooling and trapping with advantages for portable and molecular applications.

Contribution

The authors demonstrate a novel technique of current modulation of a tapered amplifier to produce GHz sidebands for laser cooling, simplifying implementation and enhancing versatility.

Findings

Successfully trapped 1.1×10^9 Rubidium 87 atoms.

Enabled wide-range, fast frequency adjustments.

Reduced power consumption and device size.

Abstract

Laser cooling of atoms usually necessitates several laser frequencies. Alkaline atoms, for example, are cooled by two lasers with a frequency difference in the Gigahertz range. This gap cannot be closed with simple shifting techniques. Here, we present a method of generating sidebands at 6.6 GHz by modulating the current of a tapered amplifier which is seeded by an unmodulated master laser. The sidebands enable trapping of 1.1*10^9 Rubidium 87 atoms in a chip-based magneto-optical trap. Compared to the direct modulation of the master laser, this method allows for an easy implementation, a fast adjustment over a wide frequency range and the simultaneous extraction of unmodulated light for manipulation and detection. The low power consumption, small size and applicability for multiple frequencies benefits a wide range of applications, reaching from atom-based mobile sensors to the laser cooling of molecules.