An Experimental and Theoretical Investigation of a 2 μm Wavelength Low-Threshold Microsphere Laser

Jibo Yu,Jiquan Zhang,Xin Wang,Meng Zhang,Pengfei Wang,Ke Tian,Yanqiu Du,Wenhao Li,Sile Nic Chormaic

doi:10.1109/jlt.2019.2958349

Jibo Yu, Jiquan Zhang + Show 7 more

Open Access

https://doi.org/10.1109/jlt.2019.2958349

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Abstract

We present our results on an experimental and theoretical investigation into a glass microsphere laser emitting at 2 μm wavelength. First, we fabricated Ho3+-doped tellurite glass fiber and measured the absorption and emission spectra, and the fluorescence lifetime. Using this fiber, a tellurite glass microsphere with a Q-factor of 2 × 106 was also prepared, and a single-mode laser output with a low threshold of 342 μW was observed using a 1150 nm laser as the pump source. The dynamic characteristics of the microsphere laser were studied theoretically by considering rare-earth ion spectroscopy, the rate equation of the rare-earth energy level, and the light-matter interactions in the microsphere. This work can be used to study laser emissions with low thresholds in rare-earth doped compound glass microresonators for a wide range of applications, such as gas sensing, integrated photonics, and medical surgery.

Highlights

I N THE past few decades, the level of research activity surrounding spherical geometry, microcavity resonators has Manuscript received September 20, 2019; revised October 28, 2019; accepted December 3, 2019
The influence of the host materials have often been overlooked in earlier experimental and theoretical investigations into microsphere lasers, including the significant aspects of characterization of the doped compound glass, Judd-Ofelt (J-O) theoretical analysis, and the study of the rate equations in rare-earth ion [31]–[33]. We investigate, both experimentally and theoretically, a microsphere laser based on Ho3+ doped tellurite glass with emissions around 2 μm
When the pump power rose above the threshold of 324 μW, single-mode lasing was observed using an optical spectrum analyzer (OSA) (AQ6375B, Yokogawa, Japan), see Fig. 2(b)

Summary

INTRODUCTION

I N THE past few decades, the level of research activity surrounding spherical geometry, microcavity resonators has Manuscript received September 20, 2019; revised October 28, 2019; accepted December 3, 2019. The influence of the host materials have often been overlooked in earlier experimental and theoretical investigations into microsphere lasers, including the significant aspects of characterization of the doped compound glass, Judd-Ofelt (J-O) theoretical analysis, and the study of the rate equations in rare-earth ion [31]–[33]. We investigate, both experimentally and theoretically, a microsphere laser based on Ho3+ doped tellurite glass with emissions around 2 μm. The lifetimes of the 2 μm and 2.8 μm emission after exponential fitting are 3.4 ms and 0.4 ms, respectively

EXPERIMENTAL CHARACTERIZATION OF THE MICROSPHERE LASER

THEORETICAL ANALYSIS