Ultrafast laser micromachining of silica aerogels

Silica aerogels are unique nanostructured materials that possess many disti nctive qualities, including extremely low densities and thermal conductivit ies, very high surface-area-to-volume ratios, and large strength-to-weight ratios. Aerogels, however, are very brittle, and are not readily shaped usi ng traditional machining operations. Ultrafast laser processing may provide an alternative for precision shaping and machining of these materials. Thi s paper discusses investigations of ultrafast laser machining of aerogels f or material removal and micromachining. The advantages of ultrafast laser p rocessing include a minimal thermal penetration region and low processing t emperatures, precision removal of material, and good-quality feature defini tion. In this work, an amplified femtosecond Ti:sapphire laser system is us ed to investigate the breakdown threshold, material removal rate per pulse, and specific issues associated with laser processing of aerogels, as well as recommendations for further investigations for these unique materials. ( C) 2001 Elsevier Science B.V. All rights reserved.