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ISSN 1064-2269, Journal of Communications Technology and Electronics, 2007, Vol. 52, No. 6, pp. 678–683. © Pleiades Publishing, Inc., 2007. Original Russian Text © V.B. Voloshinov, K.B. Yushkov, 2007, published in Radiotekhnika i Elektronika, 2007, Vol. 52, No. 6, pp. 727–733. RADIO PHENOMENA IN SOLIDS AND PLASMA Acoustooptic Interaction of Two Light Beams in a Paratellurite Crystal V. B. Voloshinov and K. B. Yushkov Received October 17, 2005 Abstract—Double acoustooptic diffraction of light in a paratellurite crystal is investigated experimentally and theoretically. The anisotropic Bragg interaction with three diffraction maxima is considered in the case when two monochromatic light beams are incident on the crystal simultaneously. For each beam, double diffraction is realized, so that the propagation direction of one of the beams coincides with the propagation direction of the second-order diffracted ray for the other beam. It is shown that the diffraction pattern consists of three diffraction maxima: two of these are formed by the zero- and second-order diffracted rays, while the third maxima is formed by the first-order diffracted rays. The possibility of summation of the radiation intensities at the diffraction maxima is analyzed. PACS numbers: 43.35.Sx, 78.20.Hp DOI: 10.1134/S1064226907060113 INTRODUCTION Light diffraction by ultrasound in crystals is widely employed in optoelectronics to control luminous fluxes [1–4]. Paratellurite (TeO2) crystals, which exhibit an extremely high acoustooptic (AO) quality are applied in AO devices [1–5]. This material allows realization of anisotropic diffraction characterized by the rotation of the polarization plane of a diffraction wave with respect to the polarization of incident light [1–4]. One of the characteristic features of the AO interaction in birefringent crystals is multiple diffraction of light by ultrasound [1, 2, 6–14], in particular, the double Bragg interaction. In the case of double diffraction, the conditions for the Bragg synchronism are fulfilled at a fixed ultrasound frequency for light scattering from the zero diffraction order into the first- and second-order diffraction maxima simultaneously [1, 2, 6, 7]. Diffraction modes with several light rays at the outputs of AO cells have recently attracted considerable interest of researchers [10–20]. In order to realize such modes, electric signals with specially chosen amplitudes, frequencies, and phases are applied to a piezoelectric transducer. In addition, an important problem in acoustooptics is coherent summation of the amplitudes of light fields, which provides for combination of several optical rays in a single total light beam [15–20]. In this study, we investigate a possible scheme of summation of the intensities of light rays. The scheme involves double diffraction of light by ultrasound in paratellurite [21]. In contrast to studies [15–18], here, two monochromatic light rays with equal frequencies and identically oriented polarization planes are incident on a cell. Light diffraction by monochromatic sound is realized. As a result of interaction, the light of six diffraction maxima is observed at the output of an AO device. The maxima are combined in three light beams. Each of the beams is formed by the rays of two diffraction maxima with identical polarization directions but different frequencies and phases. The propagation directions of incident light rays in the plane of the AO interaction are chosen with allowance for the synchronism conditions. The interaction develops in the ( 110 ) plane of a íÂé2 crystal when the wave vector of a slow shear ultrasonic wave is oriented at the angle α = 10° to the [110] axis. In the considered case of double diffraction, the sound frequencies are much higher than the acoustic frequencies in variants of the AO interaction that were investigated earlier [15–20]. 1. GENERAL SCHEME OF DIFFRACTION OF TWO LIGHT RAYS INCIDENT ON A CRYSTAL The general schematic of diffraction and the propagation directions of incident and diffracted light beams are displayed in Fig. 1. As is shown in the figure, extraordinarily polarized light beam 1 is incident on a crystal and transmitted through paratellurite. After leaving the cell, the beam has amplitude C01. Simultaneously with the first beam, extraordinarily polarized light beam 2 with amplitude C02 is incident on the crystal. The vector diagrams illustrating the photon–photon interaction [1–4] are used to describe diffraction of two beams. It is known that the length of the wave vector of acoustic waves K = 2πf/V is determined by control-signal frequency f and sound velocity V, while the wave number of light k = 2πn/ λ depends on optical wavelength λ and a crystal’s refractive index n. 678 ACOUSTOOPTIC INTERACTION OF TWO LIGHT BEAMS 1 679 [110] 2πno/λ [001] 2 α θB2 θB1 f* C21, C02 C11, C–12 C01, C–22 k3 θd K k2 I3 I2 k1 I1 Fig. 1. Directions of rays in a paratellurite-crystal AO cell. Figure 2 displays the vector diagram for the studied case of double AO interaction in a paratellurite crystal. K 2πno/λ 2πne/λ It is seen from the figure that wave vector k 1 of light beam 1 incident on ultrasound is oriented at Bragg angle θB1 relative to the acoustic-wave front, while Fig. 2. Vector diagram of the double anisotropic Bragg diffraction in paratellurite. wave vector k 2 corresponding to the light scattered into the first diffraction order is oriented at angle θd. For the the length of the wave vector of light beam 2 coincides first-order diffraction, the vector relationship k 1 + K = k 2 is fulfilled and the beam with amplitude C11 corresponding to the positive first diffraction order is observed at the exit from the crystal. Moreover, it is seen from the vector diagram in Fig. 2 that, for the firstorder diffracted light beam, the synchronism condition k 2 + K = k 3 (where k 3 is the wave vector of the second-order diffracted beam) is satisfied. Thus, in a crystal, light diffraction from the first into the second order is possible [1, 6, 7]. As is seen from Fig. 1, secondorder diffracted light waves have amplitude C21. Since, during each anisotropic diffraction transition, the polarization plane is rotated through an angle of 90°, the second- and zero-order diffracted radiation is extraordinarily polarized and the first-order diffracted light is characterized by the ordinary polarization. Note that, owing to the Doppler shift, the frequencies of the first-and second-order diffracted light beams differ from the frequency of the incident light beams by quantities f and 2f, respectively. In the considered variant of double diffraction, both light beam 2 and 1 are guided into the crystal at the Bragg angle. However, Bragg incidence angle θB2 of the second beam is chosen such that the incident radiation propagates toward the second diffraction maximum, which is formed as a result of double diffraction of the first beam. Thus, the wave vector of beam 2 has the same orientation as wave vector k 3 . It is evident that with the length of vector k 3 , because the ultrasonic frequency is much lower than the light frequency. Therefore, in the diagram, vector k 3 is common to both incident light beam 2 and the second-order diffracted beam formed from beam 1. It is obvious that, for the chosen propagation direction of light beam 2, the Bragg condition for scattering into the negative first diffraction order, which is described by the relationship k3 – k = k2, is fulfilled in the crystal. Thus, when beam 2 is diffracted, a beam that corresponds to the negative order of diffraction and that has amplitude C–12 is formed at the exit from the cell. This effect is illustrated in Fig. 1. The radiation of the negative diffraction order can be scattered repeatedly into the minus second diffraction maximum. This scattering process produces light with amplitude C–22 and is described by the vector relationship k 2 – K = k 1 . The light frequencies at the maxima of the minus first and minus second diffraction orders differ from the frequency of the incident beam by the quantities –f and −2f, respectively. The analysis of the general diffraction scheme and of the vector diagram shows that six diffraction maxima are formed at the exit from the crystal. These are combined into three light beams. The two extreme light beams consist of the zero- and second-order diffracted beams with amplitudes C01 and C–22 and amplitudes C21 and C02. As is seen from the vector diagram, all of these beams are extraordinarily polarized. The ordinarily polarized light beam at the center of the diffraction pat- JOURNAL OF COMMUNICATIONS TECHNOLOGY AND ELECTRONICS Vol. 52 No. 6 2007 680 VOLOSHINOV, YUSHKOV θB, deg 25 ters operating in the presence of nonpolarized optical radiation [23–25]. Anisotropic diffraction corresponding to point B is not employed in AO devices in the case when a high-frequency acoustic wave propagates in paratellurite far from the [110] axis [21]. The calculations have shown that the angle–frequency characteristics intersect at point B when λ = 633 nm and the ultrasonic frequency is f * = 188.4 MHz. In this situation, when the incident radiation is ordinarily polarized, the two branches of angle–frequency characteristics intersect. Ä 15 2 5 1 Ç –5 0 100 1 2 200 300 400 f, MHz Fig. 3. Frequency dependences of the Bragg angles of light incidence on an acoustic wave front for (1) ordinarily and (2) extraordinarily polarized light beams. Experimental data are shown as triangles and squares. tern is formed by the first- and minus-first-order diffracted beams with amplitudes C11 and C–12. 2. DEPENDENCES OF THE BRAGG INCIDENCE ANGLES ON THE ACOUSTIC FREQUENCY Having analyzed the vector diagram in Fig. 2, we can represent the acoustic frequency as a function of light incidence angle f in the case of the extraordinary optical polarization: V 2 2 2 f ( θ B ) = --- ( n i sin θ B – n o – n i cos θ B ), λ (1) where no is the medium’s refractive index for an ordinary wave and ni is the medium’s refractive index for an extraordinary wave [1, 2, 7, 12–14]. Refractive index ni depends on the direction of light propagation. In a similar manner, the Bragg frequency can be represented as a function of the incidence angle of ordinarily polarized light. Typical angle–frequency characteristics in paratellurite are depicted in Fig. 3. In the calculations based on formula (1), the principal refractive indexes observed in paratellurite at no = 2.26 and ne = 2.41 and a typical of λ = 633 nm were used. The velocity of shear acoustic waves was chosen to be V(10°) = 7.09 × 104 cm/s. It is seen from Fig. 3 that, for the considered geometry of interaction in a íÂé2 crystal, angle–frequency dependences θB(f) intersect at points A and B. All possible intersection points in uniaxial crystals and the corresponding geometries of the AO interaction are classified in studies [14, 22]. The Bragg diffraction mode that is observed in paratellurite and that corresponds to point A has been investigated comprehensively and is used in modulators [16, 17, 19, 20] and tunable AO fil- 3. INTENSITIES OF DIFFRACTED LIGHT IN THE CASE OF DOUBLE SCATTERING In order to analyze double scattering, we have found the light intensities at the three diffraction maxima shown in Fig. 1 for both positive and negative diffraction orders. In this study, we consider the case of phase synchronism, which ensures the highest efficiency of diffraction [1]. Let optical beam 1 be incident on a crystal. With allowance for phase ϕ1 of the acoustic wave, the system of differential equations for the complex amplitudes of the zero C01(x), positive first (C11(x)), and positive second (C21(x)) diffraction orders takes the following form [1, 7]: dC 21 dC 01 q q - = --- C 11 exp ( iϕ 1 ); ----------- = – --- C 11 exp ( – iϕ 1 ); ---------2 dx 2 dx (2) dC 11 q ----------- = --- [ C 01 exp ( iϕ 1 ) – C 21 exp ( – iϕ 1 ) ]. 2 dx The equalities C01(0) = 1 and C11(0) = C21(0) = 0 express the initial conditions. In (2), q is the factor of AO coupling and x is the coordinate oriented perpendicularly to the boundaries of the acoustic column. In a similar manner, the system of equations describing the double AO interaction for light beam 2 can be obtained: dC 02 q ----------- = --- C –12 exp ( iϕ 2 ); 2 dx dC –22 q ------------ = – --- C –12 exp ( – iϕ 2 ); 2 dx (3) dC –12 q ------------ = --- [ C –22 exp ( iϕ 2 ) – C 02 exp ( – iϕ 2 ) ]. 2 dx This system should be combined with the following initial conditions: C02(0) = 1 and C–12(0) = C–22(0) = 0. The analysis has shown that a solution to system (2) at the exit from the acoustic column at x = l can be represented in the form ql 1 C 11 = ------- sin ------- exp ( iϕ i ); 2 2 2 ql = sin ---------- exp ( 2iϕ 1 ); 2 2 2 ql C 01 = cos ---------- ; 2 2 C 21 JOURNAL OF COMMUNICATIONS TECHNOLOGY AND ELECTRONICS Vol. 52 No. 6 2007 (4) ACOUSTOOPTIC INTERACTION OF TWO LIGHT BEAMS while system (3) yields the solution 2 ql C 02 = cos ---------- ; 2 2 C –22 1 ql C –12 = – ------- sin ------- exp ( – iϕ 2 ); 2 2 (5) 2 ql = sin ---------- exp ( – 2iϕ 2 ) , 2 2 which differs from (4) in phase factors. The calculations have confirmed that, when only one light beam is incident on an AO cell, the total energy of incident light at the exit from the sound column can be collected in the second diffraction maximum at ql = 2 π; i.e., C21C *21 = I21 = 1.0 and C–22 C *–22 = I–22 = 1.0. No more than 50% of the light power incident on a crystal can be concentrated in the first diffraction order. When ql = π/ 2 , the intensity of the first diffraction maximum is I11 = I–12 = 0.5, 25% of the incident light flux is concentrated in the zero diffraction order, and 25% of the incident light flux is concentrated in the second diffraction order. The analysis of solutions (4) and (5) has shown that the light amplitudes at diffraction maxima depend on sound-wave parameters q and ϕ and on length l of the region of the light–sound interaction. The light amplitudes in the zero, first, and second diffraction orders prove to be identical; however, the wave phases are different for the maxima with positive and negative numbers. When two light beams are simultaneously incident on an AO cell, the interaction in the acoustic column develops in the same spatial region. Therefore, in relationships (2)–(5), the phases of the acoustic wave can be assumed equal: ϕ1 = ϕ2 = ϕ. Generally, the optical waves of each of the two partial diffraction maxima that, at the exit from the cell, form the first, second, and third light beams have different amplitudes, phases, and frequencies. This circumstance should be taken into account in the calculation of the resulting amplitudes of electromagnetic waves in the three beams leaving the crystal. Evidently, the light amplitudes in all of these beams are modulated with sound frequency f and the intensities in these beams are modulated with the frequency 2f. If a low-frequency receiver records only the energy characteristics of beams, beats with the frequency 2f are averaged. Then, the intensities of the three beams leaving the crystal are described by the expressions 2 ql I 1 = I 3 = 0.5 ⎛ 1 + cos -------⎞ ; ⎝ 2⎠ 2 ql I 2 = sin ------- . 2 (6) Thus, when the sound amplitude has the optimum value, i.e., when ql = π/ 2 , the light intensities at the side maxima take their minimum values: I1 = I3 = 0.5. In this situation, at the center maximum, which combines the rays of the first diffraction orders, the summation of the light-field amplitudes yields the intensity I2 = 1. The following main conclusion can be drawn: The light 681 power equal to the sum of the powers of initial optical beams cannot be collected at the center maximum, because a half of the light power incident on the cell is concentrated in two side beams. 4. EXPERIMENTAL INVESTIGATION OF DIFFRACTION IN PARATELLURITE We performed an experimental investigation on a paratellurite AO cell where a slow shear acoustic wave was excited by a piezoelectric transducer made from xcut lithium niobate. The calculation has shown that, when the length of the piezoelectric transducer is l = 1.4 cm and the ultrasonic frequency is f = 180– 190 MHz, the sound divergence is 4 mrad. The acoustic-wave velocity is oriented at the angle α = 10° to the [110] axis in the ( 110 ) plane. A helium–neon laser providing for linearly polarized emission at the wavelength λ = 633 nm served as a light source. Before being incident on the crystal, the emission had been divided into two identically polarized beams of equal intensities. The divergence of each of the incident beams was equal to 3–4 mrad, a value that is comparable to the divergence of an ultrasonic beam. In the experiments, when each of the two incident light beams was diffracted separately, the efficiency in the second diffraction order reached 70–80%. Less than 20% of the incident radiation remained in the first diffraction order. The experiment showed that the most effective double scattering was observed at the ultrasonic frequency f = 187.9 MHz. The experimental value of the acoustic frequency proved to be close to the value f* = 188.4 MHz, which had been predicted theoretically. The transducer’s electric voltage determined by the condition ql = 2 π reached the value U = 6 V, which corresponded to an ultrasonic power of 0.8 W. The dots in Fig. 4 show the experimental values of double-diffraction efficiency I21 as a function of the ultrasonic frequency. It is seen that diffraction into the second order is observed over a narrow frequency range: ∆f = 0.4 MHz. This circumstance indicates the high selectivity of the employed Bragg interaction mode. Similar results were obtained for beam 2 incident on the crystal. In addition, we have experimentally studied the multiple Bragg light scattering in the case when two extraordinarily polarized light rays are incident on the crystal. These rays were guided to the acoustic wave front at the Bragg angles, and the ultrasonic frequency was equal to the frequency of double scattering. As had been predicted theoretically, when two light rays were incident on the crystal, the diffraction pattern contained two maxima of the zero and second orders and a combined diffraction maximum of the first order. At the control-signal frequency f = 187.9 MHz, the diffractedlight intensities were measured at each of the three diffraction maxima as functions of the electric-signal voltage at the piezoelectric transducer (Fig. 5). Curve 4 JOURNAL OF COMMUNICATIONS TECHNOLOGY AND ELECTRONICS Vol. 52 No. 6 2007 682 VOLOSHINOV, YUSHKOV I21, arb. units 0.6 I, arb. units 2.1 4 2.0 1.9~ ~ 1.2 1 0.4 0.8 0.2 3 0.4 2 0 0 0 186 188 2 4 6 U, V 190 f, MHz Fig. 4. Frequency dependence of the light intensity in the second diffraction order. shows the total intensity of all of the three beams at the exit from the cell, i.e., illustrates the conservation of the optical power in the AO device. The data presented in Fig. 5 confirm that all the light at the exit from the AO cell was actually concentrated only in three light beams and that the diffraction pattern contained no other diffraction maxima. The following conclusion can be drawn from the measurement results presented in Fig. 5. There exist two diffraction modes with different behavior of diffraction intensities I1, I2, and I3 (as functions of control electric voltage U) in diffraction orders. These regions correspond to low and high intensities of double diffraction. The experiment has shown that, at a low control voltage at the transducer (U < 2 V across a load of 50 Ω), the probability of a photon’s transition from the first into the second diffraction order is small. In this case, at the combined first-order diffraction maximum, the energies of initial beams 1 and 2 are summed, I2 = I11 + I21, and light-ray intensity I2 increases with the sound power. The optimum control voltage is U = 3 V. This value corresponds to the condition ql ≅ 0.7π and agrees with the theoretical prediction. At this control voltage, the beam intensities in two extreme diffraction orders are equal and take the minimum value: I1 ≅ I3 = 0.65 ± 0.03. This value exceeds the theoretical quantity I1 = I3 = 0.5 only slightly. At the optimum signal voltage, the intensity I2 = 0.70 ± 0.03 has been recorded in the center beam, while the theoretical prediction is I2 = 1. Thus, we can conclude that the theory and experiment are in qualitative agreement. Evidently, one of the causes of the discrepancy between the experimental and theoretical results is the fact that optical and acoustic beams participating in diffraction are not plane waves. Therefore, all the incident light could not be concentrated in the second diffraction Fig. 5. Relative intensities I of diffracted light as functions of electric-signal voltage U at a piezoelectric transducer. Curves 1 and 3 correspond to the side diffraction maxima with intensities I1 and I3, respectively; curve 2 corresponds to the center maximum with intensity I2; and curve 4 corresponds to the sum of intensities I1 + I2 + I3. Experimental data are shown as squares and circles. order even when a single light beam was incident on ultrasound. The experiment has additionally confirmed that double diffraction of two light beams by monochromatic sound should be analyzed with allowance for the amplitudes and phases of light waves. Obviously, precisely because of the phase relationships, the light fluxes of initial light beams could not be concentrated experimentally in a single diffraction order with the maximum efficiency. This conclusion fits the results from [17, 19], where the effect of phase relationships on the intensities of diffracted beams has been predicted. It is seen from Fig. 5 that, over a wide range of control voltages (2 < U < 6 V), the diffraction efficiency in all of the three diffraction orders varies from 60 to 70%. This means that the optical power of incident light is characterized by an approximately uniform distribution among the three diffraction maxima. The experiment has confirmed that, at a high control voltage (U > 4.5 V) and ql > π, the intensities of light beams change only slightly, while the ultrasound amplitude grows. This circumstance means that the considered model of double AO interaction is not complete, because it disregards possible additional light-energy exchange between the rays of all of the six partial rays at the exit from an AO cell. It has been found during the investigations that, when incidence angles of light beams are fixed and the acoustic frequency varies around the value f = f *, the interaction between initial light beams 1 and 2 vanishes. Thus, at the ultrasonic frequency f = 189.0 MHz, the efficiency of double scattering is a small bounded quantity (I21 ≅ I–22 < 0.02) and the intensities of the first dif- JOURNAL OF COMMUNICATIONS TECHNOLOGY AND ELECTRONICS Vol. 52 No. 6 2007 ACOUSTOOPTIC INTERACTION OF TWO LIGHT BEAMS fraction orders are substantial (I11 ≅ I–12 > 0.9). In this situation, the light fluxes of incident beams are effectively summed in the first diffraction order. The experiment has shown that, when synchronism is lost and the mode of double diffraction is disturbed, the first-order diffracted light beams leaving the crystal are spaced by an angle of approximately 4 mrad. This angle is comparable with the divergence angles of the light beams incident on the crystal. Therefore, the structure of the light spot at the center of the diffraction pattern is complex and composed of two spots that overlap only partly. Our investigation has confirmed that the use of double diffraction makes it possible to concentrate a substantial portion of the energy of two beams incident on an AO cell in the center diffraction order. CONCLUSIONS When two light rays incident on a paratellurite-crystal AO cell are doubly diffracted in the crystal, there exist interaction modes differing in the behavior of the diffracted-light intensity as a function of the ultrasound amplitude. At a small control voltage, the intensity of the diffracted beam increases with the amplitude of the control signal. The intensities of two light rays incident on the crystal are summed at the common diffraction maximum. At a substantial ultrasound power, the energy is distributed approximately uniformly among three light beams at the exit from the AO cell and the intensities of the light rays are dependent only slightly on the acoustic-wave power. In the considered case of double AO interaction, two linearly polarized monochromatic light beams can be combined into a single beam. However, the analysis has confirmed that this combination of light beams is accompanied by a loss of light power. ACKNOWLEDGMENTS The authors are grateful to V.V. Proklov for his interest in the problem and for helpful discussions of the results. REFERENCES 1. V. I. Balakshii, V. N. Parygin, and L. E. Chirkov, Physical Fundamentals of Acoustooptics (Radio i Svyaz’, Moscow, 1985) [in Russian]. 2. A. Korpel, Acousto-Optics (Marcel Dekker, New York, 1988; Mir, Moscow, 1993). 683 3. J. Xu, R. Stroud, Acousto-Optic Devices (Wiley, New York, 1992). 4. A. Goutzoulis and D. Pape, Design, Fabrication of Acousto-Optic Devices (Marcel Dekker, New York, 1994). 5. T. Yano and A. Watanabe, J. Appl. Phys. 45, 1243 (1974). 6. A. W. Warner, D. L. White, and W. A. Bonner, J. Appl. Phys. 43, 4489 (1972). 7. V. B. Voloshinov, V. N. Parygin, and L. E. Chirkov, Vestn. Mosk. Univ., Fiz., Astron. 17, 305, (1976). 8. V. B. Voloshinov and B. Traore, Radiotekh. Elektron. (Moscow) 35, 1610 (1990). 9. S. N. Antonov, Yu. V. Gulyaev, V. M. Kotov, et al., Radiotekh. Elektron. (Moscow) 32 623 (1987). 10. V. M. Kotov, Zh. Tekh. Fiz. 63 (1), 180 (1993). 11. V. M. Kotov, Zh. Tekh. Fiz. 67 (2), 66 (1997). 12. V. Voloshinov and A. Tchernyatin, J. Opt. A: Pure Appl. Opt. 2, 389 (2000). 13. V. B. Voloshinov and A. Yu. Chernyatin, Opt. Spektrosk. 88, 1000 (2000) [Opt. Spectrosc. 88, 911, (2000)]. 14. A. Yu. Chernyatin and V. B. Voloshinov, Nelineinyi Mir 3 (1–2), 116 (2005). 15. J. C. Kastelik, M. G. Gazalet, and P. Boudy, J. Appl. Phys. 83, 674 (1998). 16. S. N. Antonov, V. V. Proklov, Yu. G. Rezvov, et al., Zh. Tekh. Fiz. 76 (1), 60 (2006) [Tech. Phys. 51, 57 (2006)]. 17. S. N. Antonov, A. V. Vainer, V. V. Proklov, and Yu. G. Rezvov, Zh. Tekh. Fiz. 77 (5), 75 (2007) [Tech. Phys. 52 (2007) (in press)]. 18. V. V. Proklov, Yu. G. Rezvov, V. N. Chesnokov, et al., Akust. Zh. 52 (1), 81 (2006) [Acoust. Phys. 52, 81 (2006)]. 19. V. V. Proklov, S. A. Antonov, A. V. Vainer, et al., in Proc. 2005 IEEE Int. Ultrasonics Symp., Rotterdam, Netherlands, 2005 (IEEE, New York, 2005), p. 49. 20. S. A. Antonov, V. V. Proklov, Yu. G. Rezvov, et al., in Proc. 2004 Int. Ultrasonics Ferroelectrics, and Frequency Control Joint 50th Anniversary Conf., Montreal, Canada, 2004 (IEEE, New York, 2004), p. 76. 21. K. B. Yushkov and V. B. Voloshinov, in Wave Electronics, Its Applications in Information, Telecommunication Systems. (Proc. VIII Int. Conf. Young Researchers, St. Petersburg, 2005) (State Univ. Aerospace Instrument, St. Petersburg, 2005), p. S1-1. 22. A. Tchernyatin, E. Blomme, and V. Voloshinov, J. Opt. A: Pure, Appl. Optics 4 (1), 16 (2002). 23. V. B. Voloshinov and V. Ya. Molchanov, Opt. Laser Technol. 27, 307 (1995). 24. V. B. Voloshinov, V. Ya. Molchanov, and J. C. Mosquera, Opt. Laser Technol. 28, 119 (1996). 25. H. Lee, Appl. Opt. 27, 815 (1988). 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