Micro structuring of sapphire and fused silica by high speed and high precision in-volume selective laser etching

Abstract

Micro structuring of sapphire and fused silica [1] is an important market e.g. the production of microfluidic devices and sensors that combine optical and microfluidic functions [2] as well as freeform microlense systems. New techniques which enable the processing of sapphire and fused silica are requested. The In-volume Selective Laser Etching (ISLE) technique is a two step process for the micro machining of sapphire and fused silica. First the sample is irradiated using fs-laser direct writing inducing material modifications within the focal volume by non-linear absorption processes. Subsequently the sample is wet etched. The use of high repetition rate fs-lasers, e.g. FCPA lasers with f=0.1-5 MHz, potentially allows for a high productivity, but can not be achieved with nowadays handling systems concerning speed without sacrificing precision and/or numerical aperture. To overcome the limitations mentioned above a scanning optics for fs-laser writing with high precision Δx=100-300 nm), high speed (v=100-300 mm/s) and large numerical aperture (NA=0.4-1.2) is developed. New results which are achieved with ISLE method in combination with the developed scanning optics will be shown and discussed.Micro structuring of sapphire and fused silica [1] is an important market e.g. the production of microfluidic devices and sensors that combine optical and microfluidic functions [2] as well as freeform microlense systems. New techniques which enable the processing of sapphire and fused silica are requested. The In-volume Selective Laser Etching (ISLE) technique is a two step process for the micro machining of sapphire and fused silica. First the sample is irradiated using fs-laser direct writing inducing material modifications within the focal volume by non-linear absorption processes. Subsequently the sample is wet etched. The use of high repetition rate fs-lasers, e.g. FCPA lasers with f=0.1-5 MHz, potentially allows for a high productivity, but can not be achieved with nowadays handling systems concerning speed without sacrificing precision and/or numerical aperture. To overcome the limitations mentioned above a scanning optics for fs-laser writing with high precision Δx=100-300 nm), high speed (v=100-...