Statistics of light in Raman and Brillouin nonlinear couplers

Statistical properties of optical fields in nonlinear couplers composed of two waveguides in which Raman or Brillouin processes (with classical pumping) are in operation and which are mutually connected through the Stokes and/or anti-Stokes linear interactions are investigated within the framework of generalized superposition of coherent fields and quantum noise. Heisenberg equations describing the couplers are solved both analytically under special conditions and numerically in general cases. Regimes for nonclassical properties of optical fields, such as sub-Poissonian photon-number statistics, negative reduced moments of integrated intensity and squeezing of quadrature fluctuations are discussed for the cases of single and compound fields. General results are compared with those from short-length approximation.Comment: LATEX, 20 pages, 19 PostScript figure

The 1/N-expansion, quantum-classical correspondence and nonclassical states generation in dissipative higher-order anharmonic oscillators

We develop a method for the determination of thecdynamics of dissipative quantum systems in the limit of large number of quanta N, based on the 1/N-expansion of Heidmann et al. [ Opt. Commun. 54, 189 (1985) ] and the quantum-classical correspondence. Using this method, we find analytically the dynamics of nonclassical states generation in the higher-order anharmonic dissipative oscillators for an arbitrary temperature of a reservoir. We show that the quantum correction to the classical motion increases with time quadratically up to some maximal value, which is dependent on the degree of nonlinearity and a damping constant, and then it decreases. Similarities and differences with the corresponding behavior of the quantum corrections to the classical motion in the Hamiltonian chaotic systems are discussed. We also compare our results obtained for some limiting cases with the results obtained by using other semiclassical tools and discuss the conditions for validity of our approach.Comment: 15 pages, RevTEX (EPSF-style), 3 figs. Replaced with final version (stylistic corrections

Quantum versus classical descriptions of sub-Poissonian light generation in three-wave mixing

Sub-Poissonian light generation in the non-degenerate three-wave mixing is studied numerically and analytically within quantum and classical approaches. Husimi Q-functions and their classical trajectory simulations are analysed to reveal a special regime corresponding to the time-stable sub-Poissonian photocount statistics of the sum-frequency mode. Conditions for observation of this regime are discussed. Theoretical predictions of the Fano factor and explanation of the extraordinary stabilization of the sub-Poissonian photocount behavior are obtained analytically by applying the classical trajectories. Scaling laws for the maximum sub-Poissonian behavior are found. Noise suppression levels in the non-degenerate vs degenerate three-wave mixing are discussed on different time scales compared to the revival times. It is shown that the non-degenerate conversion offers much better stabilization of the suppressed noise in comparison to that of degenerate process.Comment: 9 pages, 12 figures, to be published in J. Optics

Engineering squeezed states in high-Q cavities

While it has been possible to build fields in high-Q cavities with a high degree of squeezing for some years, the engineering of arbitrary squeezed states in these cavities has only recently been addressed [Phys. Rev. A 68, 061801(R) (2003)]. The present work examines the question of how to squeeze any given cavity-field state and, particularly, how to generate the squeezed displaced number state and the squeezed macroscopic quantum superposition in a high-Q cavity

Studies on Covalent Adducts of Dehydrouric Acid

The structure of 5-chloro and 5-alkoxy-5,7-dihydro-3//-purine-2,4,6-trio- nes (6 and 7-9) has been corroborated by their spectral properties and X-ray crystallography. The stereochemical model (fì)-10 of the key uricolytic intermediate was prepared using menthol as chiral auxiliary. In acidic solutions, depending on the N-substitution, the ring cleavage occurred either at the 4,9-bond 6b -» 13 (R1 = Me) or at the 3,4-bond 6c -» 14 (R1 = H). Opening of the 1,6-bond is the dominant process under alkaline conditions. Decarboxylative rearrangement into 1,3-dimethylallantoin (15) was specific for N(7)-unsubstituted derivatives. Evidence for intermediacy of the bicyclol tautomeric form was supplied by isolation of l-menthoxy-2,4-dimethyl-3,7-di- oxo-2,4,6,8-tetraazabicyclo[3.3.0]octane (16); fragmentation of 10 into 5- menthoxy-imidazolidin-2,4-dione (17) also takes place under forcing conditions. Conversely, no allantoin rearrangement was encountered in the R7*H cases; 7d underwent the pyrimidine ring fragmentation to give 5-methoxy-l- methyl-4-methylimino-imidazolidine-2-one (18) or 5-carboxamido-5-methoxy- l-methyl-4-methylimino-imidazolidine-2-one (19). A possible mechanism for these ring transformation reactions is discussed

Nano-displacement measurements using spatially multimode squeezed light

We demonstrate the possibility of surpassing the quantum noise limit for simultaneous multi-axis spatial displacement measurements that have zero mean values. The requisite resources for these measurements are squeezed light beams with exotic transverse mode profiles. We show that, in principle, lossless combination of these modes can be achieved using the non-degenerate Gouy phase shift of optical resonators. When the combined squeezed beams are measured with quadrant detectors, we experimentally demonstrate a simultaneous reduction in the transverse x- and y- displacement fluctuations of 2.2 dB and 3.1 dB below the quantum noise limit.Comment: 21 pages, 9 figures, submitted to "Special Issue on Fluctuations & Noise in Photonics & Quantum Optics" of J. Opt.