Optical injection and spectral filtering of high-power UV laser diodes

TL;DR

This paper demonstrates injection-locking of high-power UV laser diodes at 397nm, achieving stable operation and spectral purity suitable for quantum experiments by spectral filtering techniques.

Contribution

It introduces a method to stabilize high-power UV laser diodes and improve their spectral purity using injection-locking and diffraction grating filtering.

Findings

Achieved stable 120mW UV laser diode operation with ~100uW injection power.

Spectral filtering reduces spontaneous emission, making laser light indistinguishable from monochromatic light.

Validated spectral purity through photon scattering experiments on trapped calcium ions.

Abstract

We demonstrate injection-locking of 120mW laser diodes operating at 397nm. We achieve stable operation with injection powers of ~100uW and a slave laser output power of up to 110mW. We investigate the spectral purity of the slave laser light via photon scattering experiments on a single trapped Ca40 ion. We show that it is possible to achieve a scattering rate indistinguishable from that of monochromatic light by filtering the laser light with a diffraction grating to remove amplified spontaneous emission.