We develop a multi-band spectrometer with a few spatially parallel optical arms for the combined processing of their
data flow. Such multi-band capability has various applications in astrophysical scenarios at different scales: from objects
in the distant universe to planetary atmospheres in the Solar system. Each optical arm exhibits original performances to
provide parallel multi-band observations with different scales simultaneously. Similar possibility is based on designing
each optical arm individually via exploiting different materials for acousto-optical cells operating within various
regimes, frequency ranges and light wavelengths from independent light sources. Individual beam shapers provide both
the needed incident light polarization and the required apodization to increase the dynamic range of a system. After
parallel acousto-optical processing, data flows are united by the joint CCD matrix on the stage of the combined
electronic data processing. At the moment, the prototype combines still three bands, i.e. includes three spatial optical
arms. The first low-frequency arm operates at the central frequencies ~60-80 MHz with frequency bandwidth ~40 MHz.
The second arm is oriented to middle-frequencies ~350-500 MHz with frequency bandwidth ~200-300 MHz. The third
arm is intended for ultra-high-frequency radio-wave signals about 1.0-1.5 GHz with frequency bandwidth <300 MHz.
To-day, this spectrometer has the following preliminary performances. The first arm exhibits frequency resolution ~20
KHz; while the second and third arms give the resolution ~150-200 KHz. The numbers of resolvable spots are 1500-
2000 depending on the regime of operation. The fourth optical arm at the frequency range ~3.5 GHz is currently under
construction.
Some physical aspects of realizing one-, two-, and three-phonon scattering of light in the Bragg regime under specially
chosen conditions in optically anisotropic tellurium dioxide crystal are considered. The exact and closed analytical
models for describing these regimes using diagram technique of describing the orders of scattering are exploited. The
performed analysis is devoted first of all to the efficiency of light scattering in these regimes and is illustrated by
numerical estimations. Then, reasonable attention is paid to the effect of acoustic anisotropy in TeO2 -single crystals.
We consider physical principles of realizing the Bragg regime of three-order scattering of light by acoustic phonons in
birefringent media in specially elaborated case, when direct transitions between all the orders of scattering are allowed
and, moreover, the probabilities of these transitions can be electronically controlled. The exact and closed analytical
model with slightly mismatched wave numbers predicts sculpturing multi-pulse four-wave coupled states. Computer simulations for the spatial-frequency distributions of their optical components are performed. Thus, multi-pulse four-wave
Bragg solitons, originating with a two-phonon non-collinear light scattering, are uncovered in periodic birefringent media
providing direct transitions between all the light modes. The performed analysis is confirmed by the experimental studies.
We consider physical principles of realizing the Bragg regime of one-, two-, and three-phonon scattering of light in optically anisotropic crystals under specially elaborated conditions. The exact and closed analytical models for describing these regimes are developed. The performed analysis reveals an opportunity of realizing 100% efficiency of light scattering in these regimes, and computer simulations illustrate the obtained results. Possible applications lie in the fields of creating large aperture spatial modulators of light. In connection with this, the problems of optimizing the bandwidths and resolution of such modulators are studied.
We study the process of appearing three-wave solitons in the form of weakly coupled states under the action of pulsed optical pump in a two-mode square-law nonlinear waveguide. The analytical model for this stimulated process with slightly mismatched wave numbers predicts sculpturing multi-pulse optical components of three-wave coupled states. Both the analysis of sculpturing multi-pulse coupled states in non-stationary regime and the experimental studies are carried out. Then, the analysis developed is exploited to realize the binary encoded digital modulation of light based on collinear three-wave coupled states. An opportunity of applying this technique of localizing multi-pulse optical components inherent in coupled states to the problem of binary modulation of light beam is experimentally demonstrated.
Five-wave spatial Bragg solitary waves in the form of weakly coupled states, occurring with a four-order non-collinear scattering of light by acoustic wave in an optically anisotropic crystal, are recognized. An exact analytical description, including the localization conditions for multi-pulse states, is developed for these solitary waves. Additionally, we elaborate an approach to searching for the spatially localized states with so-called intermediate regime of light scattering. Spatial-frequency distributions for the optical components of multi-pulse coupled states are studied.
We consider some properties of the collinear acousto-optical interaction and principles of the binary encoded digital modulation of light based on exploiting collinear three-wave coupled states. The features of linearized dispersion relations are successfully used to show that the parametric coupling of light waves, being accomplished by the acoustic wave, modifies the dispersion relations for both the light waves and shapes two branches of nonlinear dispersion, whose curvatures are opposite in sign. The analytical model of shaping acousto-optical three-wave weakly coupled states is presented. The exact analytical solution allows deriving the localization condition for coupled states as well as simulating both spatio-frequency and phase distributions. The analysis developed was tested experimentally using the collinear Bragg regime of acousto-optical interaction in uniaxial single crystal. The experiments carried out make it possible to observe the dynamics of reshaping acousto-optic three-wave weakly coupled states under variations in the acoustic pulse width and the frequency mismatch. Applying the technique of localizing the coupled states to the problem of binary modulation of light beam, the conversion of multi-bit electronic signals into binary encoded optical pulse trains is demonstrated.
We consider physical principles of realizing the Bragg regime of two- and three-fold scattering of light in optically anisotropic crystals in specially elaborated cases, when direct transitions between all the orders of scattering are allowed and, moreover, the probabilities of these transitions can be controlled. The exact and closed analytical models for describing these cases are developed. The performed analysis reveals an optical nonlinearity governed by an external electronic signal, and computer simulations illustrate the obtained results. Possible applications lie in the fields of controlling light with light and all-optical logic-based switching. Here, in particular, all-optical multi-bit digital registers are presented.
Three- and four-wave spatial Bragg solitary waves in the form of weakly coupled states, originating with one- and two-phonon non-collinear scattering of light in anisotropic medium, are considered. The space-frequency distributions of their optical components are investigated both theoretically and experimentally.
We present both the estimation of main parameters and the previously obtained experimental data related to some algorithms and components for all-optical digital processors- multipliers. An all-optical multiplication in a mixed binary format may be designed with an array of non-collinear second-harmonic generation based optical AND-gates arranged in a square-law optically nonlinear medium. The modern approach, based on the concept of arranging light beams in space and time using the regime of spatiotemporall solitons or light bullets, is generally discussed.
Both theoretical and experimental studies of an advanced rather integrated acousto-optical processor exploiting the algorithm of digital multiplication via analogue convolution and based on collinear interaction between a pair of the co- or counter-propagating non-optical waves in crystals are presented. The regime of wave digital multiplication of multi-bit binary data streams using the intermediate mixed binary format is analyzed and tested experimentally. The specific method of digitization for the mixed-binary format signals applying the optical components of spatial solitary waves in the form of multi-pulse non-collinear three-wave weakly coupled acousto-optical states is described and algorithmically estimated.
We consider some principles of the binary encoded digital modulation of light based on exploiting collinear three-wave coupled states. The analytical model of shaping acousto-optical three-wave weakly coupled states is presented. The analysis developed is tested experimentally using the collinear Bragg regime of acousto-optical interaction in uniaxial single crystal. The experiments carried out make it possible to observe the dynamics of reshaping acousto-optic three-wave weakly coupled states under variations in the acoustic pulse width and the frequency mismatch. Applying the technique of localizing the coupled states to the problem of binary modulation of light beam, the conversion of multi-bit electronic signals into binary encoded optical pulse trains is demonstrated.
A specific case of a multi-phonon non-collinear light scattering in optically uniaxial media is presented. Compared to our previous studies, an innovation lies in the fact that now we consider passing just the quartet of incident light beams through a single crystal that is perturbed by the triplet of coherent acoustic waves. The exact and closed analytical model for describing this strongly nonlinear phenomenon is developed. In fact, specially designed regime of a four-order light scattering whit direct coupling of all the light modes, when transitions of four input light beams into four output light modes are allowed and electronically controlled, is examined. The feasibility of applying such an effect to an all-optical computing and performing an all-optical adder is analyzed.
An attempt is made to use the phenomenon of three-order light diffraction with direct transitions between all the optical modes in uniaxial single crystals for the implementation of all-optical logic-based devices. The exact and closed analytical model for describing this strongly nonlinear phenomenon is exploited to consider the feasibility of applying such an effect to perform all-optical switching. An opportunity for designing two versions of the key components for all-optical J-K flip-flops and the possibility of arranging a 3-bit digital register are revealed and algorithmically estimated.
A specific case a four-order non-collinear light scattering in anisotropic media is presented. Compared to our previous studies, an innovation lies in the fact that now we consider passing just the quartet of incident light waves through a single crystal that is perturbed by a coherent steam of acoustic phonons. The exact and closed analytical model for describing this strongly nonlinear phenomenon is developed. In fact, specially designed regime of a four-order light scattering, when transitions of four input light beams into four output light modes are allowed and electronically controlled, is examined. The feasibility of applying such an effect to perform an all-optical switching is analyzed. An opportunity for arranging the digital 4-bit register is revealed and algorithmically investigated.
Solitary waves in the form of acousto-optical weakly coupled states are studied theoretically and experimentally for digital amplitude modulation of light. Multi-bit weakly coupled states based conversion of the 1B/1B binary encoded input electronic signals into optical pulse trains in the 1B/NB-codes is experimentally demonstrated.
Specially designed regime of a two-phonon light scattering in anisotropic media, when direct transitions between all the light modes are allowed and electronically controlled, is examined analytically and numerically. A set of scopes for both electronic and all-optical switching of free-space light beams is revealed, estimated and algorithmically analyzed.
An attempt is made to use the phenomenon of a two-phonon light scattering with direct transitions between all the optical modes in uniaxial single crystals for the implementation of acousto-optical logic-based device. The exact and closed analytical model for describing this strongly nonlinear phenomenon is developed. The feasibility of applying such an effect to perform an all-optical switching is analyzed in the paper presented. An opportunity for arranging two versions of key components for all-optical J-K flip-flops is revealed and algorithmically estimated.
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