Deep trenches fabricated by laser-induced backside wet etching for guiding light

Abstract

By laser-induced backside wet etching (LIBWE), we can fabricate microfluidic channels on silica glasses. These channels have smooth bottom surfaces that can be combined with various optical detection techniques. Antiresonant guided optical wave (ARGOW) is a concept for guiding light in the system composed of a low refractive index medium surrounded by a medium with higher refractive index. The ARGOW was examined by using the wide channels (length: 17 mm, width: 1 mm, depth: 45 μm) prepared by LIBWE, whose bottom surface showed root-mean-square (RMS) roughness less than 100 nm. The LIBWE can fabricate deep trenches with high aspect ratio (~57 (length: 1mm, width: 10 μm, depth: 566 μm)). By using such deep channels, ARGOW system within a plane parallel to the top surface of glass can be fabricated. In this work, surface roughness of the sidewall of deep trenches prepared with LIBWE was evaluated, and the possibility of utilization for guiding light is discussed.