Fused quartz has been broadly used as a base material for micro-optical components and microfluidic chips due to its high optical transmittance, high hardness and high chemical stability. These characteristics make fused quartz difficult to machine using conventional mechanical or chemical processing technology. When cutting, drilling or surface microstructure machining, it is easy to produce cracks and fractures, which will reduce the machining quality. Femtosecond laser can achieve high-precision, high-quality, and non-contact processing due to its ultra-short pulse width and ultra-high peak power, which giving it unique advantages in the field of micromachining. This paper proposes a method for precision machining of fused silica by femtosecond laser with a center wavelength of 515 nm, the relationship between the depth and the roughness of the micromachining and the processing parameters had been studied. Common micro-optical elements (dammann grating) with high surface quality could be fabricated on the fused quartz surface by the proper processing parameter, which showed a good performance of beam splitting.
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