A Coupled Cavity Micro Fluidic Dye Ring Laser

TL;DR

This paper introduces a novel coupled cavity micro fluidic dye ring laser integrated into lab-on-a-chip systems, demonstrating successful design, fabrication, and characterization with tunable wavelength and switchable output coupling.

Contribution

It presents the first integrated micro fluidic dye ring laser with coupled cavities, tunability, and switchable output, advancing lab-on-a-chip laser integration.

Findings

Lasing observed at 55 μJ/mm² pump energy

Multi-mode lasing with switchable output coupling

Wavelength tunability via dye/solvent changes

Abstract

We present a laterally emitting, coupled cavity micro fluidic dye ring laser, suitable for integration into lab-on-a-chip micro systems. The micro-fluidic laser has been successfully designed, fabricated, characterized and modelled. The resonator is formed by a micro-fluidic channel bounded by two isosceles triangle mirrors. The micro-fluidic laser structure is defined using photo lithography in 10 microns thick SU-8 polymer on a glass substrate. The micro fluidic channel is sealed by a glass lid, using PMMA adhesive bonding. The laser is characterized using the laser dye Rhodamine 6G dissolved in ethanol or ethylene glycol as the active gain medium, which is pumped through the micro-fluidic channel and laser resonator. The dye laser is optically pumped normal to the chip plane at 532 nm by a pulsed, frequency doubled Nd:YAG laser and lasing is observed with a threshold pump pulse energy flux of around 55 micro-Joule/square-milimeter. The lasing is multi-mode, and the laser has switchable output coupling into an integrated polymer planar waveguide. Tuning of the lasing wavelength is feasible by changing the dye/solvent properties.