Femtosecond laser direct written computer generated holograms

In this paper we present how these volumetric CGHs can be realized using the FLDW technique in common borosilicate glass. For the design an Iterative Fourier Transform Algorithm (IFTA) (Gerchberg and Saxton, 1972) was applied, providing the required phase information of the aimed hologram. In order to convert this information most efficiently into a FLDW refractive index distribution, initially the characteristics of the femtosecond laser modified region such as the dimensions and the amount of induced refractive index were investigated. A maximum amount of 2.6·10^-3 with a modification diameter of 5μm was achieved.