Optical Properties of BDK-Doped Highly Photosensitive Sol-Gel Hybrid Film

A new organic-inorganic hybrid material doped with BDK that exhibits a large photo-induced change in optical properties is prepared by the sol-gel method. The photosensitivity of the film under ultraviolet irradiation is investigated with various exposure times. An increase in refractive index from 1.558 to 1.592 at λ = 550 nm is observed together with a 57.3% expansion in physical thickness. The film's optical thickness exhibits an exponential change with the irradiation time. The photo-decomposition of BDK organic groups confirmed by the infrared absorption spectrum contributes to the photosensitive mechanism. A first example of photo-patterning is finally presented by direct light writing.