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56We investigated the effects of teichoic acid (TA)

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We have studied anisotropic Bragg diffraction of light by ultrasonic shear waves in an optically isotropic plane-parallel layer. We have established the analytical dependences of the relative intensities and polarization azimuths of reflected and transmitted diffracted waves on the intensity of the ultrasound, the layer thickness, the angle of incidence, and the polarization azimuth of the incident light. We show that rotation of the plane of polarization of the diffracted wave is determined by the different Fresnel reflection of the s and p polarized components of the incident light in the plane-parallel layer. We have determined that in mismatched acousto-optic structures, deep amplitude modulation of transmitted and reflected light is possible which is an order of magnitude greater than the usual modulation in matched structures. Introduction.We know that mismatched acousto-optic (AO) structures in which the average refractive index undergoes jumps at the boundaries of the layer can be used for modulation of optical radiation [1-3]. In [3] it is shown that mismatched structures, perturbed by a longitudinal ultrasonic wave and based on promising acousto-optic crystals of tellurium (Te), paratellurite (TeO 2 ), quartz (SiO 2 ), bismuth germanate (Bi 12 GeO 20 ) and others, can be used for designing acousto-optic devices using both transmitted and reflected diffracted waves. For low angles of incidence of the light ϕ 1 (ultrasonic wave frequencies), the relative intensities of the diffracted waves are determined by the intensity of the ultrasound, the thickness of the plane-parallel layer, and the ratio of the refractive indices of the bounding media. The amplitude, phase, and polarization characteristics of light waves diffracted by longitudinal and transverse ultrasound in matched acousto-optic structures are considered in [4][5][6]. It is shown that for Bragg diffraction of light by ultrasonic shear waves in optically isotropic media, acousto-optic interaction of the orthogonally polarized waves occurs. According to [7], ultrasonic Gulyaev-Bleustein waves, propagating in a plane-parallel layer, can be detected by acoustooptic methods and used for modulation of light. At this time, there is no sufficiently complete theoretical description of acousto-optic conversions in mismatched acousto-optic structures, taking into account deep modulation of the light over a broad range of the acoustic spectrum for multichannel processing of the signal information.The Calculation. In this paper, we have studied the energy, polarization, and angular characteristic features of acousto-optic Bragg diffraction by ultrasonic shear waves in mismatched structures made from isotropic materials. We have established the effect of Fresnel reflection of zeroth and first order diffracted waves from the boundaries of a three-layer structure: coating-modulated layer-substrate. A diagram illustrating acousto-optic diffraction is shown in Fig. 1.In the case of a noncollinear acousto-optic interaction, the ultrasonic wave is propagated along ...