Abstract

Microprocessing of transparent and high-hardness materials such as technical glasses and crystals attracts more and more attention due to the optical and mechanical properties of mentioned materials. A notable example is sapphire—one of the most rigid materials having impressive mechanical stability, high melting point, and a wide transparency window reaching into the UV range, together with impressive laser-induced damage thresholds. Sapphire is highly desired in micro-optics and photonics or micromechanics. Nonetheless, the usage of this material is limited by the complicated 3D microfabrication of sapphire. However, femtosecond laser-based microprocessing techniques are a good alternative for sapphire processing. A remarkable example is Selective Laser etching (SLE) which allows the production of arbitrary shape structures out of glasses[1, 2]. This method includes nanogratings inscription in the volume of transparent material and subsequent etching of laser-processed material[3]. However, sapphire adoption of this technique is currently limited.

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