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1.
G. V. Kulak 《Technical Physics》1997,42(9):1055-1057
An intermediate regime for the diffraction of light on ultrasound in gyrotropic anisotropic and cubic crystals in an external
electric field is considered. A system of equations of the coupled waves, which describes acoustooptic diffraction in gyrotropic
anisotropic crystals with consideration of the electrically induced optical anisotropy for a strong interaction between light
and ultrasound, is presented. An intermediate regime for the diffraction of light on ultrasound in gyrotropic anisotropic
crystals which is close to the Bragg regime for a weak acoustooptic interaction is studied. It is shown that the diffracted
light is elliptically polarized and that the ellipticity and polarization azimuth of the diffracted wave depend on the anisotropy
of the photoelasticity, the electrically induced anisotropy of the crystal in the external electric field, the gyrotropy,
and the asymmetry of the diffraction structure.
Zh. Tekh. Fiz. 67, 80–82 (September 1997) 相似文献
2.
We show that layers of acousto-optic gyrotropic paratellurite crystals perturbed by ultrasound can be used as efficient light
modulators in transmission and reflection mode. We have established that the relative intensities of the diffracted waves
are determined by the ratio of the refractive indices of the bounding media, the intensity of the ultrasound, and the thickness
of the modulated layer. We show that for an asymmetric diffraction structure, efficient acousto-optic conversion is possible
in reflection mode, and the weak effect of the gyrotropy is due to its suppression by Fresnel reflection at the boundaries
of the layer.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 819–823, November–December, 2006. 相似文献
3.
The features of noncollinear acousto-optic interaction in gyrotropic crystals in the intermediate diffraction regime and the
regime of Bragg diffraction were investigated. The dependence of the efficiency of diffraction in gyrotropic paratellurite,
tellurium, and quartz crystals on the intensity of the ultrasonic wave, acousto-optic interaction length, and incident-light
polarization was investigated. It is shown that the gyrotropy of the crystal is responsible for the appearance of a multiple-peak
structure of the Bragg maximum. It has been established that in the case of propagation of incident and diffracted waves in
the vicinity of the optical axis of the crystal, the diffraction efficiency is independent of the polarization state of the
incident light. The results of theoretical calculations are in agreement with the experimental results obtained for uniaxial
crystals.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 1, pp. 105–110, January–February, 2000. 相似文献
4.
The amplitude-phase features of an intermediate regime of light diffraction on ultrasound in gyrotropic cubic crystals have been investigated. It is established that in the gyrotropic medium excited by ultrasound two coupled phase lattices of photoelasticity appear as a result of the rotation of the polarization planes of interacting waves. These lattices determine the polarization and energy characteristics of a diffracted light. For a gyrotropic cubic crystal of bismuth germanate, good agreement between the theoretical and experimental dependences of the efficiency of diffraction on the ultrasonic intensity in the intermediate regime close to the Bragg regime of diffraction is obtained. 相似文献
5.
G. V. Kulak 《Optics and Spectroscopy》2005,98(6):866-870
The features of the Bragg diffraction of light by ultrasound under the conditions of Fresnel reflection from the boundaries of a perturbed layer have been investigated. It has been shown that layers based on acousto-optical gyrotropic crystals perturbed by ultrasound can be used as efficient light modulators. The relative intensities of diffracted waves have been found to be determined by the relation of the refractive indices of adjacent media and by the ultrasound intensity. With an increase in the thickness of the modulated layer, the reflection and transmission coefficients of the first-order diffracted waves achieve their maxima at a lower ultrasound intensity. 相似文献
6.
We investigate diffraction of light at phase holographic-type gratings recorded by a piezoactive ultrasonic wave in gyrotropic cubic photorefractive crystals. We show that the efficiency of diffraction at a holographic grating can be increased substantially by applying a d.c. field to a crystal under the conditions of a longitudinal electrooptical effect; elliptical polarization of diffracted light is determined by electrically induced anisotropy of a crystal in the piezofield of a photorefractive grating, by the external electric field, detuning of phase synchronism, gyrotropy of the crystal, ultrasound frequency, and the time of recombination of charge carriers. 相似文献
7.
G. V. Kulak 《Journal of Applied Spectroscopy》1999,66(2):302-305
The specific features are considered of the noncollinear optoacoustic interaction in uniaxial gyrotropic quartz crystals in
an intermeadiate regime of diffraction close to the Bragg regime. A system of equations of coupled waves is presented which
describes the optoacoustic interaction in uniaxial gyrotropic crystals in the Raman-Nath, intermedaite, and the Bragg regimes
of diffraction. The dependences of the diffraction efficiency on the ultrasonic wave intensity, the optoacoustic interaction
length, and on the incident light polarization are investigated. A multispike structure of the Bragg maximum is studied that
appears in accounting for the crystal gyrotropy. A good agreement between the theoretical calculations and the known experimental
results for a quartz crystal is shown.
Mozyr State Pedagogical Institute, 28, Studencheskaya Str., Mozyr, 247760, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 2, pp. 278–281, March–April, 1999. 相似文献
8.
A theoretical investigation is carried out for an intermediate regime of optoacoustic interaction, close to the Bragg one,
by ultasonic Rayleigh surface waves in gyrotropic planar waveguides in an external electric field. A system of equations of
associated waves is presented which describes the planar optoacoustic interaction in intermediate, Raman—Nath, and Bragg regimes
of diffraction by ultrasonic surface waves in gyrotropic crystals with electrically induced anisotropy. It is shown that the
intermediate (transition) regime of optoacoustic interaction, which is characterized by an angular selectivity and by the
presence of several diffraction maxima, is the basic regime of diffraction. In this case diffracted light is generally elliptically
polarized with an ellipticity and polarization azimuth that depend on the external electric field intensity.
Translated from Zhurrnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 30–35, January–February, 1999. 相似文献
9.
S. N. Sharangovich 《Russian Physics Journal》1995,38(2):107-117
The diffraction of light beams by ultrasound with a two-dimensionally nonuniform, exponentially damped amplitude distribution in gyrotropic cubic crystals is investigated theoretically. An analytical model of strong acoustooptic interaction is constructed on the basis of self-consistent solutions of the vector-matrix partial differential equations for coupled waves written in the amplitudes of the light beam. The model can be used to determine the spatial profiles of the intensity and the polarization structure of the diffracted field for arbitrary diffraction efficiencies and geometries. Numerical simulation results are given.State Academy of Control Systems and Radio Electronics, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 8–19, February, 1995. 相似文献
10.
An intermediate regime of light diffraction by ultrasound propagating along the [001] and [110] axes of a gyrotropic cubic bismuth germanate crystal is investigated. The possibility of polarization-independent light modulation in the intermediate regime of diffraction close to the Bragg regime is shown. The dependences of the diffraction efficiency on the incident light polarization azimuth at different ultrasonic wave intensities are given. 相似文献
11.
Yu. D. Khamchukov V. V. Klubovich A. V. Myasoedov S. N. Shashkov 《Journal of Applied Spectroscopy》1999,66(2):233-239
For single crystal wafers of lead germanate cut perpendicularly to the C-axis an investigation has been made of IR transmission
and RS spectra atλ
exc
=632.8, 514.5, and 488 nm in the spectral range of 400–1800 cm−1. An interpretation of the spectra recorded is suggested. In the RS spectra specific features of line intensity distributions
are detected. The dependences of the intensity distribution in the peculiarities detected on the excitation wavelength and
the angle of incidence of exciting radiation and transmission of the reflected exciting laser beam relative to the optical
axis of illumination of the spectrometer inlet slit are investigated. The reason for the occurrence of these specific features
is suggested: the interference of RS radiation and exciting laser radiation diffracted on the non-working narrow sides of
the diffraction gratings of the spectrometer. The possibilities of amplifying the spectral lines in the RS spectra by imposing
diffracted one-mode exciting radiation on them are discussed.
Translated from zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 220–226, March–April, 1999. 相似文献
12.
We have studied conversion and interaction of a Bessel laser beam of zero order in photorefractive crystals. We have established
that in a cubic gyrotropic crystal, two Bessel light beams propagate with different wave vectors and cone angles, but with
identical conicity parameters. As the power in the Bessel light beam increases, we have experimentally observed a new optical
effect: self-action of a Bessel light beam. We have studied the effect of external influences and the parameters of the beam
itself on the process of self-refraction in photorefractive crystals.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 488–493, July–August, 2006. 相似文献
13.
14.
V. N. Belyi G. V. Kulak G. V. Krokh P. I. Ropot O. V. Shakin 《Optics and Spectroscopy》2016,121(3):424-430
Specific features of the acousto-optic diffraction of Bessel light beams propagating in the vicinity of the optical axis of a uniaxial gyrotropic crystal have been investigated. The dependences of the diffraction efficiency on the acousto-optic interaction length, ultrasound power, and polarization state of the incident Bessel light beam have been analyzed using the coupled-wave equations and the overlap-integral method. It is shown that polarization-independent diffraction of Bessel light beams is observed in paratellurite crystals, when the Bragg diffraction efficiency is independent of the polarization state of the incident beam. The physical reason for this diffraction has been established (both theoretically and experimentally) to be simultaneous implementation of two processes of anisotropic scattering, at which the Bragg synchronism conditions are satisfied for orthogonal polarized Bessel beams with elliptical polarization. 相似文献
15.
G. V. Kulak 《Journal of Applied Spectroscopy》1997,64(3):428-432
The intermediate regime of optoacoustic interaction, similar to the Bragg one, with Rayleigh surface ultrasonic waves in gyrotropic
planar waveguides is studied. A system of equations of bound waves is presented that describes planar optoacoustic interaction
in the intermediate, Raman-Natoh, and Bragg regimes of light diffraction by surface ultrasonic waves. It is shown that the
optical activity of a wavequide film favors the incident light energy pumping to diffracted light for a TE-polarization wave
and decelerates this process for an incident TM-polarization wave.
Mozyr' State Pedagogical Institute, 28, Studencheskaya St., Mozyr', 247760, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 3, pp. 412–416, May–June, 1997. 相似文献
16.
17.
A. G. Afonin V. M. Biryukov V. A. Gavrilushkin V. N. Gres’ B. A. Zelenov V. I. Kotov V. A. Maisheev A. V. Minchenko V. I. Terekhov E. F. Troyanov Yu. A. Chesnokov M. G. Gordeeva A. S. Denisov Yu. M. Ivanov A. A. Petrunin V. V. Skorobogatov B. A. Chunin 《JETP Letters》1998,68(7):568-572
A record-high particle extraction efficiency, exceeding 40%, in agreement with theoretical predictions, is achieved using
a short (5 mm long) crystal bent by 1.5 mrad. An extracted beam intensity of ∼6×1011 protons per cycle is obtained. This is five to six orders of magnitude higher than previous results.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 7, 544–548 (10 October 1998) 相似文献
18.
The problem of anisotropic Bragg diffraction of nonpolarized light by a slow acoustic wave in a TeO2 crystal is solved. Two independent acoustic waves are excited in the crystal. Nonpolarized light splits in the crystal into
two orthogonally polarized eigenmodes, either diffracting by its associated acoustic beam. Conditions under which the angles
of incidence and diffraction are the same for both diffraction processes are found. Depending on the acoustic frequency, the
diffracted light at the exit from the crystal may be represented either by a single nonpolarized beam or by two orthogonally
polarized beams with different directions and orthogonal polarizations. This may provide a high diffraction efficiency (up
to 100%) for nonpolarized light in a TeO2 crystal. Theoretical calculations are supported by experiments. Modulators capable of controlling a high-power laser operating
at a wavelength of 1.06 μm are fabricated. 相似文献
19.
Bragg diffraction of light beams by ultrasound with a curved wave front in gyrotropic cubic crystals
S. N. Sharangovich 《Radiophysics and Quantum Electronics》1994,37(3):163-173
We have investigated Bragg diffraction of light beams by ultrasound in gyrotropic cubic crystals for strong acoustoopitc interaction. We have obtained analytical solutions of the vector-matrix coupled-wave equations in partial derivatives relative to the spatial distributions of the light beams and their angular spectra. We consider the asymptotic form of the solutions in different regimes and the diffraction efficiencies. We study the transformation of the amplitude and polarization distributions with respect to the angular spectrum of the diffracted radiation under strong-interaction conditions in the field of an ultrasonic beam with a curved wave front.Tomsk Institute of Automated Control Systems and Radioelectronics. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 3, pp. 273–288, March, 1994. 相似文献
20.
Holographic phase conjugation is analyzed as a method to create a photo-refractive lens with high numerical aperture. For
this purpose a sub-wavelength hole is drilled into a metal surface directly on top of an iron-doped lithium niobate crystal.
An interference pattern generated by the light coming from this point source and a plane reference wave is recorded. By using
the phase-conjugated reference wave for read-out, a light wave being focused onto the former point source is reconstructed.
In principle, a focusing system close to the theoretical diffraction limit could be implemented by this method. The performance
of this arrangement is mainly determined by properties of the lithium niobate crystal, especially the crystal symmetry. Experimentally,
the tight holographic focusing is demonstrated. The focus width of the reconstructed wave is shown to be below 1.2 μm, which
is our spatial resolution. The diffraction efficiency obtained, however, is just 3×10−5 compared to 3×10−2 in the plane-wave case. This can be explained by experimental reasons, the inhomogeneous light intensity and limitations
originating from the crystal symmetry. We estimate that the diffraction efficiency for phase conjugation through a sub-wavelength
hole can be improved by three to four orders of magnitude by addressing the above-mentioned issues. 相似文献