Fabrication of microreactors in photostructurable glass by 3D femtosecond laser direct write

Three-dimensional (3-D) microstructuring of photostructurable glass is demonstrated by using femtosecond (fs) laser for a Lab.-on-chip device, in other words, a micro total analysis system (μ-TAS), application. The fs laser direct-write process followed by a thermal treatment and chemical etching in a HF aqueous solution produces true 3-D hollow microstructures embedded in the photostructurable glass. This technique is applied for manufacturing a microfluidic structure inside the glass. Mixing of two kinds of aqueous solutions is demonstrated in the fabricated structure. A freely movable microplate is also fabricated inside glass to control a stream of reagents in the microfluidics. To give additional functions to the fabricated microfluidics, selective metal plating of the glass is performed by the fs laser irradiation in an electroless plating solution. This paper also discusses the mechanism of photostructurable glass modification by the fs laser.