Microfabrication of 3D hollow structures embedded in glass by femtosecond laser for Lab-on-a-chip applications

Three-dimensional hollow microstructures acting as microfluidic and microoptical components were directly formed inside a photoetchable glass, Foturan, using femtosecond (fs) laser direct writing followed by post-annealing and successive chemical etching. Benefiting from a multiphoton process and a focus-shaping technique, a resolution as high as 10 μm was achieved in both the transverse and longitudinal directions. Microreactors containing microchannels, microcells, and microvalves were fabricated by this technique, and functions like sample mixing and fluid switching were demonstrated. Also, microoptics, such as micromirrors and microbeam splitters, were fabricated by this technique. The microfluidic and microoptical components were also integrated into the same chip for creating microfluidic dye lasers. A dual-color microfluidic laser array which can simultaneously emit light with wavelengths centered at 568 and 618 nm was also fabricated and its lasing properties examined.