Simultaneous parametric generation and up-conversion of entangled optical images

A quantum theory of parametric amplification and frequency conversion of an optical image in coupled nonlinear optical processes that include one parametric amplification process at high-frequency pumping and two up-conversion processes in the same pump field is developed. The field momentum operator that takes into account the diffraction and group velocities of the waves is used to derive the quantum equations related to the spatial dynamics of the images during the interaction. An optical scheme for the amplification and conversion of a close image is considered. The mean photon number density and signal-to-noise ratio are calculated in the fixed-pump-field approximation for images at various frequencies. It has been established that the signal-to-noise ratio decreases with increasing interaction length in the amplified image and increases in the images at the generated frequencies, tending to asymptotic values for all interacting waves. The variance of the difference of the numbers of photons is calculated for various pairs of frequencies. The quantum entanglement of the optical images formed in a high-frequency pump field is shown to be converted to higher frequencies during the generation of sum frequencies. Thus, two pairs of entangled optical images are produced in the process considered.     

The formation of a light field with suppressed photon fluctuations by nonlinear optical methods

A quantum theory is developed to describe optical parametric amplification under low-frequency pumping, which is observed in nonlinear photonic crystals in sequential interactions of light waves with multiple frequencies. Spatial variations of the mean number of photons and the Fano factor at signal and additional frequencies are analyzed. It is shown that a field with a sub-Poisson statistics of photons can be formed at a signal frequency which is 1.5 times higher than the frequency of pumping.     

Entangled photon states in consecutive nonlinear optical interactions

Quantum theory of two consecutive light-wave parametric interactions with aliquant frequencies produced by a common pump wave in a crystal is developed. Using the differentiation method, the unitary evolution operator of the system is reduced to an ordered form that allows the calculation of the field state and the statistical characteristics of interacting waves. It is shown that, for the initial vacuum field state, the created photons obey the super-Poisson statistics at the interacting frequencies and are in a multiparticle entangled state.     

An analogue of the Kapitza-Dirac effect

This paper concerns the quantum motion of a relativistic electron in the field of opposite electromagnetic waves of different frequencies. An effect has been found that is similar to the Kapitza-Dirac effect. However, as distinguished from the latter, scattering here is inelastic: due to the coherent transition from one wave to the other of photons of different frequencies the electron is either accelerated or decelerated. In this case, applification of the wave of the lower or of the higher frequency takes place, respectively.     

Phonon-polariton and band structure of electro-magneto-acoustic SH wave propagation oblique to the periodic layered piezoelectric structures

Electro-magneto-acoustic SH waves propagating oblique to the periodic layered piezoelectric structures are studied under the coupling of the acoustic wave and the electromagnetic wave. Band structures of the so-called piezoelectric superlattice and phononic/photonic crystal are given both at acoustic frequencies and at optical frequencies. For the periodic layered piezoelectric structures, phonon-polaritons (the coupling modes of the phonons and photons) are found not only happening near the center of the Brillouin zone (in the long-wavelength limit) at acoustic frequencies, but also being able to appear in the whole Brillouin zone at optical frequencies. Appearing of these phonon-polaritons may provide a way to design a new type of acousto-optic devices.     

A calibration technique for frequency domain photothermoacoustics

Photoacoustic (or more precisely, photothermoacoustic) signals are generated by the absorption of photons, expressed as acoustic waves, and can be related to the incident laser fluence rate. Here a calibration procedure for frequency domain (FD) photoacoustics is presented which utilizes the relationship between photoacoustic (PA) signal amplitude and laser fluence rate. The sample is irradiated with a continuous wave laser which is amplitude modulated at varying frequencies. Applying the calibration procedure to the PA detected signals, a linear relationship is obtained between the fluence rate and the signal amplitude.     

Generation of high-energy photons with large orbital angular momentum by compton backscattering

Usually, photons are described by plane waves with a definite 4-momentum. In addition to plane-wave photons, "twisted photons" have recently entered the field of modern laser optics; these are coherent superpositions of plane waves with a defined projection hm of the orbital angular momentum onto the propagation axis, where m is an integer. In this Letter, we show that it is possible to produce high-energy twisted photons by Compton backscattering of twisted laser photons off ultrarelativistic electrons. Such photons may be of interest for experiments related to the excitation and disintegration of atoms and nuclei, and for studying the photoeffect and pair production off nuclei in previously unexplored experimental regimes.     

Model for modulated and chaotic waves in zero-Prandtl-number rotating convection

The effects of time-periodic forcing in a few-mode model for zero-Prandtl-number convection with rigid body rotation is investigated. The time-periodic modulation of the rotation rate about the vertical axis and gravity modulation are considered separately. In the presence of periodic variation of the rotation rate, the model shows modulated waves with a band of frequencies. The increase in the external forcing amplitude widens the frequency band of the modulated waves, which ultimately leads to temporally chaotic waves. The gravity modulation, on the other hand, with small frequencies, destroys the quasiperiodic waves at the onset and leads to chaos through intermittency. The spectral power density shows more power to a band of frequencies in the case of periodic modulation of the rotation rate. In the case of externally imposed vertical vibration, the spectral density has more power at lower frequencies. The two types of forcing show different routes to chaos.      

Dielectric polarization in the Planck theory of sonoluminescence

Sonoluminescence observed in the cavitation of liquid H2O may be explained by the Planck theory of SL, which treats the bubbles as collapsing miniature masers having optical waves standing in resonance with the dimensions of the bubble cavity. Microwaves are shown to be created from the Planck energy of the standing waves, provided the bubble wall can be treated as a perfect blackbody surface. Liquid H2O is strongly absorbent in the ultraviolet and there the bubble approaches a Planck blackbody enclosure. The microwaves are created at frequencies proportional to the bubble collapse velocity only to be promptly absorbed by the rotation quantum states of the H2O and other bubble wall molecules. The microwaves are absorbed discretely at rotation line frequencies, or continuously by dipole rotation at frequencies from 1 to 30 GHz. In the liquid state, molecular rotation of the H2O molecule is hindered and the microwave energy is rapidly turned into bending energy by intermolecular collisions. Subsequently, the bubble wall molecules may thereby ionize and produce visible photons. The microwaves create intense electrical fields in the bubble wall by dielectric polarization. If the gases adjacent to the bubble wall undergo electrical breakdown, free electrons are created, thereby providing sonoluminescence with a magnetic field effect.     

Estimation of critical and viscous frequencies for Biot theory in cancellous bone

The use of Biot theory for modelling ultrasonic wave propagation in porous media involves the definition of a "critical frequency" above which both fast and slow compressional waves will, in principle, propagate. Critical frequencies have been evaluated for healthy and osteoporotic cancellous bone filled with water or marrow, using data from the literature. The range of pore sizes in bone gives rise to a critical frequency band rather than a single critical frequency, the mean of which is lower for osteoporotic bone than normal bone. However, the critical frequency is a theoretical concept and previous researchers considered a more realistic "viscous frequency" above which both fast and slow waves may be experimentally observed. Viscous frequencies in bone are found to be several orders of magnitude greater than calculated critical frequencies. Whereas two waves may well be observed at all ultrasonic frequencies for water-filled cancellous bone at 20 degrees C, it is probable megahertz frequencies would be needed for observation of two waves in vivo.     

Coalescence of photons in the interaction process between a quantized plane electromagnetic wave and an electron. II

In this part of the article the coalescence of photons of a quantized plane electromagnetic wave on an electron is considered. The coalescence into one of two photons with parallel impulses and different frequencies of a non-polarized electron is analyzed. The kinematics of the process is studied in detail. The differential and complete sections of the process are obtained and analyzed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 57–61, February, 1977.In conclusion the author would like to express his thanks to V. G. Bagrov and D. M. Gitman for a useful discussion of the problems raised in this article.     

Magnetic polaritons in four-sublattice magnetic systems of the GzFx type

Magnetic polaritons in four-sublattice magnetic compounds of the space symmetry D¹⁶_2h with magnetic ordering of the G_zF_x and G_z types, like KMnF₃, RbFeF₃ etc., are considered. Dispersion curves of mixed states of photons and all four magnetic modes are given for some peculiar directions of propagation. The interaction between photons and high-frequency (optic) magnetic modes is shown to be significantly weaker than that between photons and low-frequency spin waves.     

Phase transitions of the first kind as radiation processes

Crystallization and vapor condensation are considered as the processes of sequential penetration of single atoms/molecules into condensate. In the course of these transitions the transitive radiation must be generated, which would carry away the liberated latent heat by photons of characteristic frequencies. The transient radiation is examined by the general Ginzburg-Frank theory. The emission of defined frequencies determined by the values of liberated latent heat is confirmed by analyses of several experiments of authors and other researchers.     

Quantum processes in a two-mode laser field

The probabilities of the emission of a photon by an electron and e ⁺ e ^?-pair photoproduction in a field which is a superposition of two electromagnetic plane waves with different frequencies and propagating in the same direction are obtained. The case where the frequencies of the two modes are commensurate is studied in detail. This case is interesting primarily because of the existence of effects due to the interference of amplitudes, corresponding to a different number of photons absorbed from different modes but having the same total 4-momentum. It is shown that the optimal field for observing interference effects is a field such that the ratio of the mode frequencies is 3. The probabilities of radiation and pair-photoproduction processes in the field of a monochromatic plane wave and in a two-mode field, obtained by splitting the initial wave into two waves, are compared. It is shown that the total probability of the emission of a photon by an electron in a two-mode field is lower than and the probability of pair photoproduction is higher than the probabilities of the same processes in the initial wave. The increase in the pair-photoproduction probability is explained by the fact that additional channels for reactions which are forbidden in the initial monochromatic field open up in a two-mode field.     

Combination of polarized photons on an unpolarized electron

The combination of two polarized photons with parallel momenta and different frequencies into one on an unpolarized electron is considered. The degrees of circular and linear polarization are studied in detail.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 20–27, August, 1977.We thank Professor V. G. Bagrov for helpful comments on the problems discussed here.     

Superluminal propagation of evanescent modes as a quantum effect

Contrary to mechanical waves, the two‐slit interference experiment of single photons shows that the behavior of classical electromagnetic waves corresponds to the quantum mechanical one of single photons, which is also different from the quantum‐field‐theory behavior such as the creations and annihilations of photons, the vacuum fluctuations, etc. Owing to a purely quantum effect, quantum tunneling particles including tunneling photons (evanescent modes) can propagate over a spacelike interval. With this picture we conclude that the superluminality of evanescent modes is a quantum mechanical rather than a classical phenomenon.     

Radiophysics

The propagation of magnetostatic waves in a ferromagnetic waveguide created by a step bias field is studied by numerical methods. Bias field configurations and frequencies are taken such that the width of the magnetic waveguide accommodates either only bulk waves or surface and bulk waves in combination. This work is an extension of earlier works, in which the propagation of surface waveguide modes was considered.     

Specific features of the propagation of electromagnetic waves in a waveguiding structure with superconducting film and metamaterial

The propagation of electromagnetic waves in a rectangular waveguide containing layers of common dielectric and metamaterial with a negative refractive index separated by a thin film of a superconductor of the second type in the mixed state is considered. The possibility of amplifiying waves at frequencies lower than the cutoff energy due to the energy of an Abrikosov vortex lattice moving in the superconductor is demonstrated.     

等离子体波背景下的光子Berry相位

利用光学度规将强激光脉冲激发的电子等离子体波描述为有效几何背景.借助于广义相对论中弯曲时空下的Maxwell方程组得到了探针光子在等离子体中电子等离子体波背景下(被处理为有效度规)所满足的运动方程及光子的Hamilton表达式.导出了电子等离子体波对光子Berry相位贡献的解析表达式并且对光子在真空中Berry相位的修正做了数值估算. 关键词： 电子等离子体波 等离子体 Berry相位     

Damping rates of waves in a switched magnetoplasma medium:longitudinal propagation

The interaction of a circularly polarized electromagnetic wave with a switched-on magnetoplasma medium is considered. A static magnetic field in the direction of propagation is assumed to be present, resulting in longitudinal propagation. The incident wave splits into three waves whose frequencies are different from that of the incident wave. It is shown that these waves ultimately damp out if the plasma is even slightly lossy. The damping of the waves is interpreted in terms of their attenuation with distance and decay with time as they propagate in the lossy plasma. The attenuation-length and decay-time constants of the waves are obtained, and their dependence on the incident-wave frequency and the gyrofrequency is examined. Optimum parameters for an experiment to detect these waves are suggested