Raman study of structural transformations of titania coatings induced by laser annealing

The first microscopic investigation of laser annealing of optical coatings is reported. Amorphous TiO2 coatings were ion sputtered onto Si wafers at room temperature. We show, using Raman spectroscopy, that upon laser annealing, the amorphous coatings were transformed into microcrystals of anatase structure at lower laser intensity and into a mixture of anatase and rutile structures at higher intensity.