139 GHz UV phase-locked Raman laser system for thermometry and sideband cooling of $^9$Be$^+$ ions in a Penning trap

TL;DR

This paper presents a 139 GHz UV phase-locked Raman laser system for precise thermometry and potential sideband cooling of $^9$Be$^+$ ions in a Penning trap, utilizing advanced frequency translation and phase locking techniques.

Contribution

It introduces a novel method for phase locking UV lasers at 139 GHz using electro-optic modulation and nonlinear frequency conversion, enabling applications in ion cooling and quantum measurements.

Findings

Successful phase locking at 139 GHz confirmed via stimulated Raman transitions.

Demonstrated frequency translation from infrared to ultraviolet domain.

Potential for implementing sideband cooling and quantum logic in Penning traps.

Abstract

We demonstrate phase locking of two ultraviolet laser sources by modulating a fundamental infrared laser with 4th-order sidebands using an electro-optic modulator and phase locking of one sideband to a second fundamental infrared laser. Subsequent sum frequency generation and second harmonic generation successfully translates the frequency offset to the ultraviolet domain. The phase lock at 139 GHz is confirmed through stimulated Raman transitions for thermometry of $^9$Be$^+$ ions confined in a cryogenic Penning trap. This technique might be used for sideband cooling of single $^9$Be$^+$ ions as well as sympathetic cooling schemes and quantum logic based measurements in Penning traps in the future.