Femtosecond holography in planar optical waveguides

摘要

Holograms recorded in planar optical waveguides by 30 fs pulses from the second harmonic of a Ti:Sapphire laser (λ is about 400 nm) are investigated. The 20 μm thick films of dichromated gelatin (n_2 = 1.54) deposited on a polished quartz substrate (n_1 = 1.456) is used as a planar waveguide model. The recording pulses enter the planar waveguide through its upper surface. Reconstruction in the waveguide regime is investigated for the cases when λ ≈ 633 nm and λ lies between 1150 and 1250 nm.