Optofluidic ring resonator laser with an edible liquid laser gain medium.

Wonsuk Lee,Da Bin Kim,Myoung Hoon Song,Dong Ki Yoon

doi:10.1364/oe.25.014043

Abstract

We demonstrate a biocompatible optofluidic laser with an edible liquid laser gain medium, made of riboflavin dissolved in water. The proposed laser platform is based on a pulled-glass-capillary optofluidic ring resonator (OFRR) with a high Q-factor, resulting in a lasing threshold comparable to that of conventional organic dye lasers that are mostly harmful, despite the relatively low quantum yield of the riboflavin. The proposed biocompatible laser can be realized by not only a capillary OFRR, but also by an optical-fiber-based OFRR that offers improved mechanical stability, and is promising technology for application to in vivo bio-sensing.

Highlights

Optofluidic lasers have been subject to intensive research over the last few decades, for their potentials as bio-sensing platforms [1, 2]
We demonstrate a biocompatible optofluidic laser with an edible liquid laser gain medium, made of riboflavin dissolved in water
The proposed laser platform is based on a pulled-glass-capillary optofluidic ring resonator (OFRR) with a high Q-factor, resulting in a lasing threshold comparable to that of conventional organic dye lasers that are mostly harmful, despite the relatively low quantum yield of the riboflavin

Summary

Introduction

Optofluidic lasers have been subject to intensive research over the last few decades, for their potentials as bio-sensing platforms [1, 2]. While bio-lasers with green fluorescent protein (GFP) or Indocyanine green (ICG) dye have been reported [10, 11], aqueous riboflavin and/or flavin mononucleotide (FMN) solution, which are abundant and widely found vitamin in nature and its derivative, were utilized as liquid laser gain media in recent studies [12, 13] These riboflavin/FMN lasers have been realized with Fabry–Pérot (FP) microcavities and/or small droplets, which have difficulties in achieving superior lasing characteristics due to low Qfactors. The lasing threshold is estimated to be as low as 15.2 μJ/mm, which is comparable to that of conventional optofluidic lasers with non-biocompatible organic dyes [6], such as rhodamine, owing to the extremely high Q-factor of the glass capillary OFRR [14, 15] that provides optical feedback for the lasing. Small footprint of the OFRR laser combined with recent advances in photonic waveguide inscription technique on a substrate [16], we can foresee potential integration of this laser with endoscopic systems, which can open up many possibilities for in vivo bio-chemical sensing/analysis

Experimental

Results and discussion

Summary