Laser micromachining of the materials using in microfluidics by high precision pulsed near and mid-ultraviolet Nd:YAG lasers

Both near-ultraviolet (UV) laser and mid-UV laser micromachining on materials have been investigated systematically. The materials used in this research are sapphire, silicon, and Pyrex glass that are commonly used in microfluidic applications. Cutting, marking and surface ablation of those materials have been produced by direct writing using a high-speed x–y galvanomechanical beam positioner. Laser ablation results, including ablation rate and precision, are discussed. The results show that the both ablation rate and precision of laser micromachining depend on several factors, including focus length, beam feed rate (cutting speed), the pulse repetition rate and the absorption coefficient of the materials. The result indicates that the laser ablation process of these materials could be a mixed of photothermal and photochemical processes when using a near nanosecond pulse laser. The UV (355 nm) laser micromachining process, however, appears to be dominated by a photothermal process than those of mid-UV (266 nm) laser.