Oleg B. Serov

Geometric-optical reconstruction of a wavefront

A new method of achromatic wavefront reconstruction by geometric-optical reflection of the reconstructing radiation from surfaces with constant phase difference between the object and reference waves is theoretically described and experimentally realized. Methods distinction from holographic one is discussed. Femtosecond laser pulses are used for recording in the experiment.

Geometric-optical reconstruction of a wavefront experimental realization with femtosecond laser pulses

Abstract The mechanism of wavefront reconstruction by geometric-optical reflection of reconstruction radiation from surfaces with constant phase differences between the object and reference waves has been investigated. The main difference between this mechanism and a holographic one is the absence of diffraction of the reconstructing radiation by the periodic structure and as a consequence the achromatism of the reconstruction process. Incoherent continuous radiation and ultrashort laser pulses were used in the experiments. The effect of achromatic reconstruction has been obtained after recording the interference of counterpropagating 30–40 fs pulses from an Al 2 O 3 :Ti 3+ laser in bulk media.

Achromatic reconstruction of femtosecond holograms in the planar optical waveguide.

Holograms were recorded by 30 fs laser pulses in 20 microm film of dichromated gelatin on the polished quartz substrate and reconstructed in the waveguide mode. The geometric-optical regime of waveguide hologram reconstruction was obtained: the direction of the reconstructed beam was observed to be independent on the reconstructing wavelength within the hologram spectral selectivity band. We discuss the possibility of producing achromatic waveguide optical elements containing only a few periods.

Femtosecond holography in planar optical waveguides

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 (n2 = 1 .54) deposited on a polished quartz substrate (n1 = 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.

Diffraction properties of femtosecond holograms

The effect of geometric-optical wave front reconstruction is investigated. Femtosecond holograms, which demonstrate both diffraction and geometric-optical mechanisms of reconstruction, were obtained. The waveguide variant of the geometric-optical wavefront reconstruction and the ultrashort pulses temporal reconstruction are discussed.

Recording of interference fringe structure by femtosecond laser pulses in samples of silver-containing porous glass and thick slabs of dichromated gelatin

The recording geometry and recording media for the method of achromatic wavefront reconstruction are discussed. The femtosecond recording on the thick slabs of dichromated gelatin and the samples of silver-containing porous glass was obtained. The applications of the method to ultrafast laser spectroscopy and to phase conjugation were suggested.