Study on Laser Induced Backside Etching Applied in Micro-optical Elements Fabrication

摘要

Laser induced backside etching technique is applied in the micro and nanomachining of transparent dielectric materials used for optical elements by direct laser irradiation with the assistance of an liquid or solid medium as absorbed layer. By employing such technique, samples with low surface roughness and by low etch threshold of laser fluence can be achieved which will be promisingly raise the yield of micro-optical elements. Ultrashort pulsed UV laser (1=355 nm) and fiber laser (1=1064 nm) were explored in the etching of binary and three dimensional micro structures on fused silica with micro and submicro size. A micro grating with the grating constant of 25 mm was obtained on the silica using polished Alumina ceramic pieces as absorber. The depth of trench is 5 mm. Additionally, the parameters of optical structures will varied correspondingly with different absorbers using in the laser process of induced backside etching according to experiments.