We present a novel technique for engraving microscopic 2D patterns in one step with a UV pulsed laser by means of a versatile programmable approach. The laser beam is divided to an expanded low energy signal beam which is spatially modulated by a LCD modulator and a higher energy pump beam with a plane homogeneous wave front. Both beams are superposed in a highly magnesium doped photorefractive lithium-niobate crystal where an energy transfer towards the weaker signal beam takes place. The spatially modulated and amplified signal beam is then de-magnified and imaged onto the surface where the image has to be engraved. The need for the coherent amplifier rises out of the fact that LCDs are unable to withstand the high energy throughput required for etching. The combination of the amplifier with the amplitude modulator leads to a faster and more flexible solution than laser marking with pixel-by-pixel raster-scan, or fixed mask projection mode. Such a technique can thus be applied to identify valuable items by imprinting a smart and personalised 2D code onto its surface.

We present a novel technique for engraving 2D patterns in one step with a UV pulsed laser by means of a versatile programmable approach. The spatial light modulation is actually performed by a reflective liquid crystal display instead of a mask. As these devices are unable to withstand the high energy throughput required for etching, the modulated beam is amplified by two-wave mixing in a nonlinear optical medium such as lithium niobate crystal optimised for the UV interaction. This technique provides a faster and more flexible alternative to laser marking with pixel by pixel raster-scan or fixed mask projection mode and e.g. can be applied to identify valuable items by imprinting a code onto the surface.

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