Microdrilling of sheet materials with femtosecond laser pulse shaped by computer generated hologram

Abstract

We report microdrilling of sheet materials, especially fused silica glasses by femtosecond laser processing with a computer generated hologram (CGH). We design a CGH with long-focal-depth to efficiently extend optical damage in the depth direction resulted by femtosecond laser irradiation. We fabricate through microholes approximately 1µm in diameter at the exit surface through 500µm fused silica glass sheet using the CGH without translating the sample in the depth direction and post-process such as wet etching. The drilled holes are examined using a scanning electronic microscope (SEM). It is difficult to drill the through microholes in glass materials by laser processing using only focusing lenses. This work provides a novel microdrilling technique using femtosecond laser processing with CGH.We report microdrilling of sheet materials, especially fused silica glasses by femtosecond laser processing with a computer generated hologram (CGH). We design a CGH with long-focal-depth to efficiently extend optical damage in the depth direction resulted by femtosecond laser irradiation. We fabricate through microholes approximately 1µm in diameter at the exit surface through 500µm fused silica glass sheet using the CGH without translating the sample in the depth direction and post-process such as wet etching. The drilled holes are examined using a scanning electronic microscope (SEM). It is difficult to drill the through microholes in glass materials by laser processing using only focusing lenses. This work provides a novel microdrilling technique using femtosecond laser processing with CGH.