Abstract

Femtosecond laser micromachining is a laser processing technology with proven potential for the fabrication of a wide range of photonic devices [1, 2]. In the context of developing integrated components for micro-fluidics, a key issue is the machining of high aspect ratio micro and nano-channels, and the use of diffraction-free Bessel beams for this purpose has attracted much attention [3,4]. However, although Bessel beams possess several attractive characteristics for this purpose, we show here that their practical use for high aspect ratio micromachining requires a careful selection of focussing and pump laser parameters. We report results of a systematic study of Bessel beam micromachining of structures of diameter < 5μm in fused silica, and we describe conditions under which high quality and high aspect ratio structures can be reproducibly obtained.

© 2009 IEEE