A customized CO2 laser micromachining system was used forthe generation of phase holographic structures directly on the surface of fused silica (HPFS®7980 Corning) and Borofloat®33 (Schott AG) glass. This process used pulses of duration 10μs and nominal wavelength10.59μm. The pulse energy delivered to the glass workpiece was controlled by an acousto-optic modulator. The laser-generated structures were optically smooth and crack free. We demonstrated their use as diffractive optical elements (DOEs), which could be exploited as anti-counterfeiting markings embedded into valuable glass-made components and products.
Wlodarczyk, K. L., Weston, N. J., Ardron, M., & Hand, D. P. (2016). Direct CO2 laser-based generation of holographic structures on the surface of glass. Optics Express, 24(2), 1447-1462. https://doi.org/10.1364/OE.24.001447