Unidirectional single-frequency operation of a continuous-wave Alexandrite ring laser with wavelength tunability.

Xin Sheng,Michael J Damzen,Ara Minassian,Goronwy Tawy,Juna Sathian

doi:10.1364/oe.26.031129

Abstract

High resolution spectroscopy, metrology and quantum technologies (e.g. trapping and cooling) require precision laser sources with narrow linewidth and wavelength tunability. The widespread use of these lasers will be promoted if they are cost-effective, compact and efficient. Alexandrite lasers with a broad tuning band pumped efficiently by low-cost red diodes are a potential candidate, but full performance as a precision light source has not been fully achieved. We present in this work the first continuous-wave (CW) and single-frequency operation of a unidirectional diode-end-pumped Alexandrite ring laser with wavelength tunability. An ultra-compact bow-tie ring cavity is developed with astigmatic compensation and a novel 'displaced mode' design producing CW output power > 1 W in excellent TEM00 mode (M2 < 1.2) when using a low brightness pump (M2 ≥ 30). Wavelength tuning from 727 - 792 nm is demonstrated using a birefringent filter plate. This successful operation opens the prospects of precision light source applications.

Highlights

With the development of the high power red-diode laser, diode-pumped Alexandrite (Cr3+:BeAl2O4) lasers have become more widely investigated [1,2,3,4,5,6,7,8,9,10,11,12,13]
We report the successful demonstration of a unidirectional single-frequency wavelength-tunable CW Alexandrite ring laser under continuous diode-pumping at 638 nm with an ultra-compact design
We have reported the first demonstration of unidirectional single-frequency operation of a diode-end-pumped Alexandrite ring laser in CW operation with wavelength tunability

Summary

Introduction

With the development of the high power red-diode laser, diode-pumped Alexandrite (Cr3+:BeAl2O4) lasers have become more widely investigated [1,2,3,4,5,6,7,8,9,10,11,12,13]. A Q-switched bi-directional Alexandrite ring laser [12] and a Q-switched ring system in unidirectional single-longitudinal mode operation achieved by injection seeding under pulsed diode-pumping have been developed for LIDAR applications [13]. We report the successful demonstration of a unidirectional single-frequency wavelength-tunable CW Alexandrite ring laser under continuous diode-pumping at 638 nm with an ultra-compact design.

Compact linear diode-end-pumped Alexandrite laser

Diode-end-pumped unidirectional Alexandrite ring laser

Summary and outlook