A coupled cavity micro-fluidic dye ring laser

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 µm 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 µJ/mm 2 . 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.

Bleaching and diffusion dynamics in optofluidic dye lasers

“…This has stimulated a large effort in integrating fluidics and optics in lab-on-a-chip microsystems, 1 partly defining the emerging field of optofluidics, as recently reviewed by Psaltis et al 2 and Monat et al 3 Among the investigated components are miniaturized fluidic dye lasers, also referred to as optofluidic dye lasers. [4][5][6][7][8][9] The so far reported optofluidic dye lasers are pulsed in order to have a short interaction time between the dye molecules and the pump light, thus suppressing the formation of triplet states unsuitable for lasing. This contrasts macroscopic continuous-wave dye lasers where the suppression is mediated by a jet flow of the dye solution with typical velocities of several m/s.…”

“…This strategy has been central to the so far reported microfluidic dye lasers. [4][5][6][7][8][9]11,12 However, the very different scaling of ⌫ D and ⌫ v with w offers an alternative and attractive replenishment mechanism in micron-scale systems. Usually the convective term v · ٌc is driving the replenishment, but if ⌫ D ӷ max͑⌫ v , ⌫ 0 ͒ we have the freedom to completely turn off convection and entirely rely on diffusion.…”

Finite-element simulation of cavity modes in a microfluidic dye ring laser

“…1 which corresponds to the planar cavities studied experimentally in Refs. [3,5,6]. The cavity resembles a classical Fabry-Perot resonator and consists of two dielectric isosceles triangles with…”

“…In this paper we consider a geometry resembling that of Refs. [3,5,6] and offer a full wave study of the TE modes in the cavity. The resonance wave-patterns of the cavity modes support the ray-tracing view and we are also able to explain the mode-spacing of the spectrum in terms of standing waves.…”

Doppler-Based Flow Rate Sensing in Microfluidic Channels

“…This activity has led to the development of various novel devices, such as optofluidic lasers and tunable optical devices and sensors to name a few. Several review papers describe the activity in this field [25][26][27][28][29][30][31][32][33][34].…”