On-Chip Single-Mode Optofluidic Microresonator Dye Laser Sensor

Optofluidic dye laser devices have great potential as coherent light sources for lab-on-a-chip applications such as sensing and spectroscopy applications, owing to their promising properties such as wide wavelength-tunability, proper microfluidic integration, and an extremely miniaturized footprint. The wide emission spectrum of dye molecules and narrow free spectral range of ring resonators, make these lasers inherently multi-mode. In this article, two polydimethylsiloxane-based miniaturized optofluidic ring resonator dye lasers are numerically designed and investigated. First, multi-mode lasing from a single optofluidic ring resonator with a spectral linewidth of 10 nm and a threshold energy density of $2.2~{\mu }\text{j}$ /mm2 is demonstrated. Then, by exploiting two coupled optofluidic ring resonators and Vernier effect, single-mode lasing at a center wavelength of 566 nm with a spectral linewidth as small as ${5.36}\times {10}^{-{4}}$ nm is achieved. Moreover, simulations demonstrate the sensitivity of 500 nm/RIU for the proposed dye laser sensor.