Anatolii S Chirkin

Entangled and squeezed photon states at consecutive and simultaneous quasi-phase-matched wave interactions

The results of quantum analysis of the light generated by consecutive and simultaneous quasi-phase-matched (QPM) wave interactions in periodically poled nonlinear crystals (PPNCs) are presented. In the case of the consecutive interactions of waves with multiple frequencies ω ,2 ω and 3ω, the parametric amplification at low-frequency pumping is investigated. Generation of the quadrature-squeezed light at frequencies ω and 3ω in the 2ω frequency pumping field, the photon statistics and correlation as well as the entanglement properties for photons produced at different frequencies are studied. In the case of simultaneous QPM spontaneous parametric down-conversion processes in single PPNC, the main attention is paid to obtaining the polarization-entangled states at the collinear geometry of the wave interaction.

Consecutive parametric interactions of light waves with aliquant frequencies

The process of parametric amplification with low frequency pumping in the case of aliquant frequencies of interacting waves has been studied. It has been shown that this process can be realized in a periodically poled LiNbO3 crystal. It has been established that in periodically poled nonlinear crystals the regime of exponential changing intensity of interacting waves can be implemented. The highest possible conversion efficiency in the parametrically amplified wave reaches approximately 70%.

Realization of quasi-phase-matched parametric interactions of waves of multiple frequencies with simultaneous frequency doubling

It is shown that nondegenerate optical parametric amplification of three waves with multiple frequencies ω, 2ω, 3ω and frequency doubling can be quasi-phase-matched simultaneously in media with spatially modulated nonlinear susceptibility. This provides the conditions for 100%-efficient frequency conversion of a pump wave (3ω) to signal one (2ω). Examples of simultaneous realization of parametric amplification for waves with multiple frequencies and second optical harmonic generation in lithium niobate crystals with a regular domain structure are given.

Formation and conversion of the polarization-squeezed light

Abstract We consider polarization-squeezed (PS) light generation in anisotropic Kerr medium. The fluctuations of the Stokes parameter either S 2 or S 3 are suppressed in PS light. We show the possibility to transform PS light into light with sub-Poissonian statistics by linear conversion (phase plate and analyser). The quantum properties of the second harmonic (SH) generated by frequency doubling of the PS light are investigated.

Four-mode entangled states in coupled nonlinear optical processes and teleportation of two-mode entangled CV state

We consider the forming of a four-mode entangled state for continuous variables (CV) in coupled optical parametric processes. The processes comprise one down-conversion process and two up-conversion ones. Such interactions can simultaneously be realized in a single aperiodical nonlinear photonic crystal. To reveal the entanglement between continuous variables at generated frequencies, the different criteria of the separability have been applied. We also consider teleportation of two-mode entangled CV state using the created four-mode state. It is shown that in the proposed scheme the fidelity of entangled CV teleportation can be almost perfect.

Interaction of two polarization modes in a spatio-periodic nonlinear medium: generation of polarization-squeezed light and quantum non-demolition measurements of the Stokes parameters

The possibility of formation of polarization-squeezed light in the case of the interaction of two orthogonally polarized waves in a spatio-periodically Kerr-like medium is considered. In such a quantum polarization state of light the fluctuations of one of the Stokes parameters are less than in the coherent one. Both linear and nonlinear energy exchange between polarized modes are very important for the formation of the non-classically polarized light. For the first time we offer and analyse the procedure of the quantum non-demolition measurement (QND) of the Stokes parameters of light. Conditions of realization of the QND measurement are formulated in the general case.

Transformation of photo-counting statistics by non-linear light conversion

It is known [1–3] that the statistical properties of the electrons emitted by a detector, which registers a light beam, contain information about light radiation statistics. This method has recently been widely used to measure the statistical properties of laser radiation [4]. In analysing non-linearly-transformed laser or thermal radiation, this method can give information about the non-linear process and also additional data on the statistics of the transformed radiation.

Parametric amplification of light waves at low-frequency pumping in aperiodic nonlinear photonic crystals

The process of nondegenerate optical parametric amplification in a low-frequency pump field that includes the traditional process of parametric amplification at high-frequency pumping and two up-conversion processes is investigated. Such coupled interactions can be simultaneously realized in an aperiodic nonlinear photonic crystal (ANPC) i.e., in a crystal with an aperiodic change of sign of the nonlinear wave coupling coefficient. ANPCs can be created by the method of superposition of nonlinearity modulations by three functions for each of which the quasi-phase-matching condition is met for one of the processes involved in the interaction. In addition to the results obtained from a direct numerical solution of the original coupled equations with spatially varying wave coupling coefficients, the results of their solution containing effective constant wave coupling coefficients are presented. An approach that allows the calculation of these coefficients to be simplified considerably has been developed. The two methods have been found to yield closely coincident results for the characteristics of the processes studied here. A LiNbO3 ANPC has been used as an example to calculate the tuning characteristics of the process, its dynamics, the frequency bands of parametric amplification, and the effect of a random deviation from the quasi-phase-matching conditions on the wave interaction efficiency.

Formation of a nonclassical polarization state in an isotropic gyrotropic nonlinear optical medium

The quantum problem of the two polarization modes of coherent light propagating through an isotropic gyrotropic medium with cubic nonlinearity is solved. The possibility of producing a polarization-squeezed state in such a medium is shown. The efficiency of suppression of Stokes parameter fluctuation as a function of the characteristics of the medium is investigated.

Parametric image amplification at low-frequency pumping

We develop for the first time the quantum theory of parametric image amplification at low-frequency pumping. Such a process can be implemented by coupled consecutive three-frequency optical interactions. As a result, besides the amplified optical image on the signal frequency, there are two other images with frequencies which are below the pumping frequency. The theory developed takes into account the diffraction effect and group mismatch of interacting waves. For the interacting waves the expressions for mean photon numbers and signal-to-noise ratios are deduced and the dependence of these parameters on the interaction length and coordinate at the image plane are studied.