The optimal acoustooptic interaction length in raman nath diffraction is investigated by using deliberately designed apparatus working with pure water. Raman nath diffraction, optimum interaction length, ultimate diffraction efficiency 1. The ideal raman nath diffraction slightly deviated when the klein cook parameter was increased from 0 to 1 for low phase delay values and for large phase delay, the characteristics of the bessel function disappeared. We report the aomrn capacity to be employed as phase modulator in pumpprobe modulation transfer spectroscopy in atomic vapors. Download scientific diagram a ramannath diffraction regime b bragg diffraction regime from publication. Raman nath nonlinear diffraction in second harmonic generation raman nath nonlinear diffraction in second harmonic generation.
From the frequency dependence of the optical transmission characteristics of raman nath acousticoptic diffraction, the dynamic equations and steadystate solutions of a twodimensional raman nath acoustooptic bistable system are derived. Raman nath light diffraction on acoustophotorefractive holographic gratings that was recorded in cubic photorefractive crystals according to a synchronous detection mechanism was investigated. In the problem of the diffraction of light by a supersonic wave, at normal incidence of the light, the solution of the system of differencedifferential equations of raman and nath, for the amplitudes of the diffracted light beams, is reduced to the integration of. Kapitsadirac scattering problem is solved in ramannath approximation without restrictions on the. Mixed phase and absorption thin gratings diffraction. An analog computer program which calculates the intensity of the light scattered into the various diffraction orders has been adapted for use on a digital computer. Applica tions to laserbeam deflection, guidance, modulation, coupling. However, thin enough gratings will tend to operate in the raman nath regime because the index modulation must be large for a thin grating to produce appreciable diffraction. We present an analytic theory of the diffraction of matter waves by a lattice in the quasibragg regime, by which we. The distribution of the energy in each diffractive order follows bessel function1. Sound velocity and diffraction intensity measurements. Light diffraction by two ultrasonic waves of frequency ratio 1. Perturbations in the form of holes are etched into the slab waveguide cladding or preferably into the core of the waveguide thereby changing the effective refractive index of regions within the core.
An optical wavelength selective device is provided that is particularly useful as a demultiplexer. Pdf enhancement of nonlinear ramannath diffraction in two. Anthracene is found to be more efficient than water in this respect while naphthalene and sugar are more efficient than lithium niobate. Cerenkov diffraction is defined by the longitudinal quasiphase matching condition, nonlinear raman nath diffraction satisfies only the transverse. Measurement of the intensity of progressive ultrasonic waves by means of raman nath diffraction. Evolution of the nonlinear raman nath diffraction from near field to far field dongmei liu,1 dunzhao wei,2 min gu,1,yong zhang,2,4 xiaopeng hu,2 min xiao,2,3 and peng han1 1school of physics and telecommunication engineering, south china normal university, guangzhou 56, china 2national laboratory of solid state microstructures, nanjing. Optical diffraction by inhomogeneous volume objects. Whitten department of chemistry, university of massachusetts lowell, lowell, massachusetts 01854, usa. We derive a simple analytical expression for the populations in different diffraction orders. Acoustic attenuation has also been measured in anthracene over a frequency range of 10 to 150 mhz. The model is based on the individual and simultaneous occurrences of phasegrating diffraction and the doppler effect and optical phase modulation and photonphonon scattering. Acoustooptic interaction in ramannath acoustooptic. Atomwave diffraction between the ramannath and the bragg. These are a system of infinite coupled differential equations used to describe the diffraction of light from acoustic waves or thick gratings, or in the theory of the free electron laser, or the interaction of radiation with multilevel systems.
Measurements were taken of 1 order diffracted light intensities for some raman nath parameter values, as a function of the phase shift between the sound beams. In case of the raman nath diffraction, however, greater parallelism of the photon beam is required and bigger diameter of this. Characterization of cu2znsns4 particles obtained by the. Raman nath diffraction our expressions for the optical. In this system, feedback is realized by use of a diffracted light beam to control the frequency of the acousticoptic driver. Raman and nath showed that under certain conditions the ultrasound field can be con sidered as a pure opticalphase grating. Analysis and applications of optical diffraction by gratings. Diffraction of collinear correlated photon pairs by an. Usually differential methods are employed to account for the light transmitted for volume media.
In this study, for the diffraction of light by acoustic waves in liquids, an equation for the diffracted light intensities was obtained in terms of klein cook parameter using time varying permittivity in maxwells equations. It was shown that the diffraction efficiency in sillenitetype gyrotropic crystals depended weakly on the incident light polarization and the external electric field strength. We study kapitzadirac diffraction of a boseeinstein condensate from a standing light wave for a square pulse with variable pulse length but constant pulse area. Acoustooptic interaction in ramannath acoustooptic diffraction.
Raman and nath have obtained a difference differential equation, giving the amplitude of any diffraction line. Theory of second harmonic generation in a chirped 2d. Raman nath diffraction, bragg diffraction coherence. This type of diffraction occurs at an arbitrary angle of incidence. Osa twodimensional ramannath acoustooptic bistability. Diffraction of light by sound waves in optically isotropic. Raman nath theory, and amplitude transmittance theory.
Compact acoustooptic modulator operating in the purely. A detailed analytical study of optical scattering from a parallel ultrasonic setup is presented in which an optical beam is scattered by a surface acoustic wave that. The intensity of light diffracted by the diffraction grating is 10. A compact electron gun for timeresolved electron diffraction. These are a system of infinite coupled differential equations used to describe the diffraction of light from acoustic waves or thick. This arrangement is similar to the one which was utilized for examination of ultrasound diffraction of collinear correlated photon pairs within the bragg regime. Zankel an abstract submitted to the school for advanced graduate studies of. Raman nath diffraction is modified differently with respect to the geometrical and structural. The device is made from a planar slab optical waveguide material transmissive to light. Finally, we present a method to obtain the ramannath acoustooptic diffraction without the optical phase modulations. Finally, we present a method to obtain the raman nath. Light diffraction by acoustophotorefractive dynamic. As is well known, debye and sears in america and lucas and biquard in france discovered, in 1932, that a beam of light after passing through a supersonic field breaks up into a fan of diffraction.
The diffraction of light by ultrasound has been measured at 53 mhz in anthracene, naphthalene, and sugar. A partial wave analysis of the vector wave equation describing the propagation of a light wave is given, and analytic solutions of the equation are obtained in the raman nath and bragg regions of diffraction. Based on a generating function method, an analytical expression for the raman nath like diffraction has been derived and compared with earlier work. Analysis of kapitzadirac diffraction patterns beyond the. Fraunhofer diffraction, fresnel diffraction, spatial filtering, holography acoustooptic diffraction.
Then the optimum interaction length, the suitable dimensions of the transducer, and the required index difference dominated by the ultrasonic frequency and power for achieving the ultimate efficiency are analyzed. A function of 4 variables is defined, which is the solution of the raman nath equations. The raman nath regime is observed at relatively low acoustic frequencies f and a small acoustooptic interaction length l typically, f raman nath acoustooptic diffraction, and a new model of raman nath acoustooptic diffraction is presented. A timedependent risk assessment for broken compact fluorescent lamps.
We present an analytic theory of the diffraction of matter waves by a lattice in the quasibragg regime, by which we mean the transition region between the. These are raman nath diffraction and bragg diffraction 4. On examination of light diffraction by a monochromatic acoustic wave, two limiting regimes are distinguished first of all the regimes of raman nath and bragg. Raman nath diffraction is observed with relatively low acoustic frequencies, typically less than 10 mhz, and with a small acoustooptics interaction length. Ca and mn cosubstituted bi 1x ca x fe 1x mn x o 3 x 0 and 0. Raman nath diffraction by means of thicknessshear oscillating atcut quartz crystal resonator abstract. One major issue preventing this type of solar cells from achieving competitive efficiency is impurity phases and structural defects in the bulk of the absorber. Observation of ramannath optical diffraction in the phase. Diffraction of light by two ultrasonic beams of frequency. In addition to such classical special cases of diffraction as bragg and raman nath diffraction, we also consider some cases of the diffraction of light by sound in. Nath1 later solved this equation, and found a limited. The two types of disorders are realized by introducing random fluctuations in the position and width of onedimensional 1d driven atomic lattices. Raman nath diffraction is observed with relatively low acoustic frequencies, typically less than 10 mhz, and with a small acoustooptic interaction length.
The plane in which this grating is located can be imaged outside of the acoustic medium and experimentally studied with a photodetector. A result shows the dependence of various scattered orders on the incident angle. Gustavo forte, alberto lencina, myrian tebaldi, and nestor bolognini optical diffraction by inhomogeneous. Pdf we study second harmonic generation via nonlinear ramannath diffraction in an optical superlattice that maintains a periodic modulation of the. The coupled wave theory of raman and nath diffraction is extended to the case of thin anisotropic holographic media with grating vector parallel to the medium boundaries. Introduction the features of ramannath rn acoustooptic diffraction are with short interaction length and multiorder diffraction. We present an analysis of atomic diffraction due to the interaction of an atomic beam with a pair of gaussian light pulses. Bragg and raman nath diffraction regimes up to current research in photonics materials. Measurement of the intensity of progressive ultrasonic waves by means of raman nath diffraction citation for published version apa.
We show that for grazing incidence, the use of a moving grating can increase the diffraction angle for raman nath diffraction, but not for bragg diffraction. Osa criterion for bragg and ramannath diffraction regimes. In the last decade, cu2znsns4 czts has been a promising earthabundant, nontoxic candidate material for absorption layers within thinfilm solar cells. Acoustic parameter measurements by acoustooptic diffraction. Perturbations in the form of holes are etched into the slab waveguide cladding or preferably into the core of the waveguide thereby changing the effective refractive index of regions within the. Analysis and optimum design of a portable qswitch based. A method is presented for measuring the ramannath parameter by an acoustically diffracted lightbeam of one acoustic wavelength width. Solutions for the wave amplitudes, diffraction efficiencies, and angular mismatch sensitivities are given in transmission geometries for the case of mixed dielectric and. Acoustooptic devices chapter 10 physics 208, electrooptics peter beyersdorf 1. In this article, acoustooptic interaction in raman nath acoustooptic diffraction has been discussed. The raman nath diffraction pattern can contain many diffraction orders with a symmetrical distribution of light intensity. Previous studies of raman nath optical diffraction have emphasized the characteristics of the light distribution in either the nearfield or the farfield of the optical phase grating produced by an acoustic beam. Rietveld refinement, morphological, vibrational, raman. Theory of second harmonic generation in a chirped 2d nonlinear optical superlattice under nonlinear raman nath diffraction andrey m.
A method is described for the measurement of the velocity of sound in various liquids, based on the raman nath theory of lightsound interaction. We investigate ramannath diffraction corresponding to nearbragg diffraction. Evolution of the nonlinear ramannath diffraction from. We investigate the effects of geometrical and structural disorders on perfectly asymmetric diffraction pad in raman nath regime. The structural, morphological, vibrational, raman, optical and electrical properties of codoped and pristine compounds were carried out. Acoustooptic modulators in ramannath diffraction regime. Ramannath approximation for diffraction of atom in the laser field of. Aomrn, a compact acoustooptic modulator operating purely in the raman nath diffraction regime, extended the tools employed in laser spectroscopy as optical phase modulators. We show that for grazing incidence, the use of a moving grating can increase the diffraction angle for. Measurement of the intensity of progressive ultrasonic. Pdf the ramannath equations revisited researchgate.
Diffraction of light by supersonic waves in solids nature. Ramannath diffraction grating national research council. Light diffraction by ultrasonic pulses at normal incidence is studied as well in the raman nath region low frequencies as in the bragg region high frequencies. These are raman nath diffraction and bragg diffraction. An experiment which uses a planoconvex atcut quartz crystal resonator vibrating in 5th overtone thicknessshear mode the resonant frequency is about 5 mhz as a raman nath diffraction grating is presented. Pdf atomic diffraction in counterpropagating gaussian. By studying the relations between the power of the diffracted light and its origin in the ultrasonic field, we found that the phase of the diffracted light is modulated temporally and spatially by the ultrasonic wave. A compact raman converter for uvvis spectrometers patrick j. Kirensky institute of physics, krasnoyarsk 660036, russia.
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