Collinear dual-color laser emission from a microfluidic dye laser

Collinear dual-color laser emission on a chip is obtained from a liquid dye mixture flowing through an optical microcavity. Soft lithography has been used to fabricate the microfluidic channels and integrate the optical resonator. The laser cavity, of nanoliter volume, is made of two parallel gold mirrors coated on the end faces of optical fibers and integrated into a polydimethylsiloxane chip. Such a design allows a simple but efficient coupling of the laser emission with an optical fiber. The amplification medium is composed of rhodamine 6G and sulforhodamine, dissolved in a common ethanol solution. When the dye mixture is optically pumped by a pulsed and frequency-doubled Nd:YAG laser, simultaneous laser emission at wavelengths 559 nm and 597 nm is observed, showing yellow and red colors with a complete spatial overlap within the single output beam. Moreover, the overall laser efficiency for the dye mixture system is significantly increased compared to that for the individual dyes. (c) 2006 American Institute of Physics.