Femtosecond laser written optofluidics in alumino borosilicate glass
Abstract Femtosecond Laser Irradiation followed by Chemical Etching (FLICE) is a powerful technique for prototyping three dimensional microfluidic structures in glass. Direct inscription of optical waveguides, by the same femtosecond laser, enables rapid fabrication of optofluidic devices for chemistry or biology applications. As a matter of fact, substrates where FLICE is known as most effective, such as fused silica, are not optimal for laser inscription of high contrast optical waveguides, thus limiting the potentials of this technology. Here we show that it is possible to apply FLICE also to a commercial alumino borosilicate glass, where very complex and low loss photonic circuitry has been demonstrated recently. Besides optimizing the irradiation parameters to achieve hollow structures with high aspect ratio, we investigate the etching dynamics and the micro morphology of the etched regions. As a test for the technique, we realize an optofluidic device composed of a microchannel and two intersecting optical waveguides.