We discuss the theoretical and experimental investigation of acousto-optic dispersive tunable filters, based on quasi-collinear geometry of light-sound interaction in a tellurium dioxide single crystal. The geometry uses the effect of strong acoustic anisotropy in the paratellurite as well as peculiarities of acoustic wave reflections at the free boundary of the crystal. A mathematical concept for determination of optical, electrical, and constructional parameters of the filters is developed. Different experimental acousto-optic filters intended for femtosecond pulse shaping are designed and tested. Preliminary experiments are performed in a subpetawatt optical parametric chirped pulse amplification laser system. The experimental data conform completely with the predicted data.

Adaptive acousto-optic technique for femtosecond laser pulse shaping

Acousto-optics

In the paper, we developed a dispersive method for transmission function synthesis of collinear and quasi-collinear acousto-optic tunable filters. General theoretical consideration was performed, and modelling was made for broadband and narrowband signals. Experimental results on spectral shaping of femtosecond laser emission were obtained. Binary spectral encoding of broadband emission was demonstrated.

Advanced spectral processing of broadband light using acousto-optic devices with arbitrary transmission functions.

Acoustic field structure simulation in quasi-collinear acousto-optic cells with ultrasound beam reflection.

Influence of acoustic anisotropy in paratellurite on quasicollinear acousto-optic interaction.

https://ir.nctu.edu.tw:443/bitstream/11536/27961/1/000182553400032.pdf

Subcollinear acousto-optic tunable filter based on the medium with a strong acoustic anisotropy

The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mismatch of Bragg condition. The wavelength range may extent in several times the range of ordinary isotropic diffraction on the grating of the same spacing and thickness. Theoretical explanation of this phenomena and experimental results of widerange diffraction in BaTiO3 photorefractive crystal are also presented.

https://ir.nctu.edu.tw:443/bitstream/11536/29007/1/000174066500001.pdf

Alexei K. Zaitsev

Papers

Subcollinear acousto-optic tunable filter based on the medium with a strong acoustic anisotropy

Anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals with extended wavelength range