Nano-Silicon Sol-Gel Film Refraction Index Modulation with Femtosecond Laser

Solid State Phenomena Vol. 154 (2009) pp 101-106

Antonela Dima, Massimo Gagliardi, Dun Liu, Walter Perrie, Craig J. Williams, Ivo Rendina, Geoff Dearden, Ken G. Watkins

Patterned structures were created by exposing SiO2 sol-gel films containing nano-silicon particles to a Clark MXR CPA-2010 fs laser (387 nm). A refractive index variation of 0.2 was obtained, similar to that of polymer films, however in an entirely superior stability class (structural, chemical, thermal, radiation, etc). The useful optical range of refractive index modulation is beyond 800 nm, respectively near-IR. Material characteristics were investigated with atomic force microscopy (AFM), Raman spectroscopy and spectro-ellipsometry measurements. Material properties were also investigated on different substrates in order to determine the influence of substrate type in laser processing.