Antoni Sliwinski

INVESTIGATION OF AMPLITUDE AMD PHASE OF LIGHT DIFFRACTED BY AN ULTRASONIC WAVE

Keywords: light diffraction by ultrasound, acoustooptics, amplitude and phase in diffracted orders.

Acoustically induced light polarization effects in isotropic media

Isotropic media which become anisotropic in the presence of an acoustic wave are demonstrated to act as optical polarizors. In contrast to traditional polarizing plates or rotators, the final state of polarization of light passing through a crystal with ultrasonically induced anisotropy, can smoothly be controlled by varying the acoustic parameters. The main diffraction and polarization effects are visualized in the case of fused quartz and dense flint.

Photoacoustic spectra of YAG:Cr3+ and Ce3+ crystals

Photoacoustic spectroscopy method has been applied to study nonradiative processes in the excited states of Ce3+ and Cr3+ ions in YAG crystals. A comparative analysis between photoacoustic and absorption spectra has been performed.

On the polarization of light diffracted by ultrasound

If light is diffracted by ultrasound in an isotropic medium with acoustically induced birefringence, the state of polarization is modified in each order of diffraction with respect to the initial state of polarization of the incident light wave. In the present paper, some polarization effects are discussed in the case of normal light incidence. In general a rotation of the main polarization plane occurs, together with a change of the ellipticity. However, while the former effect always takes place, the latter only occurs in the case of ultrasonic light diffraction of the intermediate type. Some experimental measurements are included in case of argon laser light being diffracted by an ultrasonic wave propagating in fused silica (SiO2).

Polarization effects at acousto-optic interaction in anisotropic medium

Polarization effects that arise during diffraction of an arbitrarily polarized light by an acoustic wave in an anisotropic medium are studies both theoretically and experimentally. Peculiarities of these effects in the cases of isotropic and anisotropic scattering of the light are considered in detail. Results of polarization state measurements performed with a paratellurite acousto-optic cell in the zeroth order of diffraction are presented as well.

Acousto-optics in Poland

Polish achievements in acousto-optics are reviewed, including optical holographic interferometric methods for ultrasonic fields and vibrating transducer examination, ultrasonic light diffraction phenomena and their modulation problems, material examination of anisotropic liquids and solids, and construction of acousto-optical devices. Topics reflect research being conducted in university centers in Gdansk, Gliwice, Poznan, and Warsaw. The studies are described and illustrated by means of arbitrarily chosen examples. Over one hundred references are cited.

Near field of light diffracted by ultrasound in an isotropic medium with acoustically induced anisotropy

A theoretical model is presented for the study of the near field of light diffracted by ultrasound in an isotropic medium which becomes birefringent in the presence of an acoustic wave. Due to the interference with the sound wave, the diffracted light wave in its near field is seen to act as a quasi-monochromatic light wave which is partially polarized. The degree of coherence ins sen to coincide with the degree of polarization and can be controlled acoustically. Hence coherent laser light can be transformed into incoherent light by sending it through an isotropic material with acoustically induced birefringence. In the experimental part of the work, the non-diagonal elements of the diffracted light beam coherency matrix were measured and a good agreement with the theoretical model was obtained.

Numerical and experimental comparison of polarization effects in ultrasonic light diffraction in intermediate range in isotropic SiO2

In the ultrasonic light diffraction phenomena in an isotropic medium in the intermediate range (between Raman-Nath and Bragg) variations in polarization state of diffracted light have been predicted and experimentally observed. In the paper some experimental and numerical results for 0 order of light diffracted by ultrasonic wave of 50 MHz frequency are presented. A possibility of continuous control of the polarization state from linear to elliptical or circular against the Raman-Nath parameter has been confirmed in good agreement between theoretical and experimental values.

Ultrasonic control of light polarization in fused silica

Optical polarization effects in an isotropic medium with ultrasonically induced anisotropy are discussed. For parameters in the intermediate diffraction regime, the possibility is shown to change acoustically the state of light polarization in a continuous way from linear to elliptical or circular

Higher Order Bragg Diffraction of Light by Ultrasound: Theory and Experiment

For the phenomenon of ultrasonic light diffraction, the possibility is shown to create Bragg effects at higher order Bragg angles. To establish these effects, the diffraction must take place in the intermediate diffraction regime. The maximum intensity obtained in a particular diffraction order at the corresponding Bragg angle is demonstrated theoretically and experimentally for the orders 1, 2 and 3.