Microfabrication of gratings inside a transparent material using femtosecond laser processing with computer generated hologram

Abstract

The purpose of this paper is to fabricate phase gratings inside bulk polymethylmethacrylate (PMMA) more productively by femtosecond laser processing with a computer generated hologram (CGH). We aim at to develop high-throughput micromachining methods by femtosecond laser pulses using a CGH. The CGH transforms input femtosecond laser intensity distribution into an arbitrary intensity distribution such as dot-array and straight-line. Our method with a CGH has a key advantage over “direct-writing” which involves a lot of sequential processing steps to move and stop the sample stage. In the grating fabrication, we had a good result: the CGH reduced the throughput time by about 0.5%.The purpose of this paper is to fabricate phase gratings inside bulk polymethylmethacrylate (PMMA) more productively by femtosecond laser processing with a computer generated hologram (CGH). We aim at to develop high-throughput micromachining methods by femtosecond laser pulses using a CGH. The CGH transforms input femtosecond laser intensity distribution into an arbitrary intensity distribution such as dot-array and straight-line. Our method with a CGH has a key advantage over “direct-writing” which involves a lot of sequential processing steps to move and stop the sample stage. In the grating fabrication, we had a good result: the CGH reduced the throughput time by about 0.5%.