摘要:

Negative feedback control of cavity losses of actively mode-locked andQ-switched GSGG:Cr:Nd lasers were employed for stabilization of the temporal parameters of ultrashort pulses.

ISSN:0950-0340    

DOI:10.1080/09500349014550011

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The parabolic fourth moment equation for a plane wave is integrated numerically using an adaptive grid algorithm. Results are compared with those from an accurate, but far less efficient, operator splitting method, and agree very closely. The adaptive approach has several advantages over current fixed grid methods. The primary one is that significant reductions in computer memory usage can be obtained without a concomitant increase in run time. It is also ideally suited for accurate integration of the fourth-moment equation for an extremely large range of values of both the scattering parameter, Γ, and the wave propagation distance.

ISSN:0950-0340    

DOI:10.1080/09500349014550021

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

An analytic approximation to the optical refractive-index spectrum of atmosphere turbulence is presented.

ISSN:0950-0340    

DOI:10.1080/09500349014550031

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The recently introduced Hermitian phase operator allows a phase-state representation of the single-mode light field. We find the requirement that a light field is in a physical state, that is, has finite energy moments, imposes strict and simple continuity conditions on the phase-amplitude distribution. We exploit these conditions to examine the physical intelligent and minimum-uncertainty states associated with the number-phase uncertainty relations, including those involving the Hermitian phase operator and its sine and cosine forms. The single number-state is found to be the only physical exact intelligent state and also the only physical exact minimum-uncertainty state for all the uncertainty relations considered. We construct states which are both physical states and approximately intelligent states. Under certain conditions coherent states, ideal squeezed states and the number-phase intelligent states associated with the Susskind-Glogower cosine and sine operators are found to be both physical states and approximately number-phase intelligent states for the phase operators considered here.

ISSN:0950-0340    

DOI:10.1080/09500349014550041

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Propagation in a Kerr medium of a system of equal-frequency light waves has been studied, each of the waves being involved in two four-wave mixing processes. Competition of these processes is shown to result in non-integrability and chaos. A stochastic regime of evolution sets in if the input values of the wave amplitudes differ strongly enough from the ones corresponding to the integrable limit connected with the system symmetry. Another condition for the chaos—strong energy exchange between the waves—is realized when the medium and radiation parameter values have the same order of magnitude as those required to obtain enhanced phase-conjugate reflection due to degenerate four-wave mixing. Various manifestations of stochastic instability of the system of light waves under experimental conditions are also discussed.

ISSN:0950-0340    

DOI:10.1080/09500349014550051

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Laser-induced continuum structures (LICS) can be produced by a strong laser embedding a low-lying atomic state into a flat atomic continuum, which leads to a tunable asymmetric Fano resonance of adjustable width that can be probed by a second weak laser. In this paper the effects on LICS of transitions caused by the embedding laser between the original atomic continuum and a second atomic continuum are studied in the Markoff approximation by means of Laplace transform methods. Formal results correct to all orders are presented in terms of aT-matrix approach. Numerical calculations are presented which include continuum-continuum coupling correct to the lowest power of the embedding laser intensity. The time evolution of the pure LICS Fano profile is also shown.

ISSN:0950-0340    

DOI:10.1080/09500349014550061

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A positive and a negative branch confocal unstable resonator with magnification |M| = 10 and with an intracavity spatial filter have been applied to a high-gain short-pulse u.v. pre-ionized XeCl laser. The performance of both resonators has been investigated and compared.

ISSN:0950-0340    

DOI:10.1080/09500349014550071

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The dielectric permittivity tensor ϵ(FE) is introduced, which is defined on a set of the evolution operators FEcharacterizing a change of the electric field strength E at a transition from point to point in a spatially dispersive medium. It allows one to use the complete sets of plane-wave solutions of Maxwell equations, including the Voigt waves, for problems of electrodynamics in anisotropic media. An operator of refractive indicesNDis found for a plane electromagnetic wave in an anisotropic medium with spatial and time dispersion.

ISSN:0950-0340    

DOI:10.1080/09500349014550081

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The photon field dynamics of a single non-decaying mode of a quantized electromagnetic field in a binomial state interacting with a three-level system is studied non-perturbatively. It is found that the phenomenon of collapse and revival is not only sensitive to the initial photon statistics, but also to photon density, coupling constants and detunings.

ISSN:0950-0340    

DOI:10.1080/09500349014550091

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The Fraunhofer approximations of the first, second and third kinds are applied to the propagation of the cross-spectral density function of coherence theory. Important differences between the conditions for validity and mathematical structure of these three approximations are described. Applications of these approximations to inverse problems are also discussed. From this work it appears possible to refocus a radio telescope to image objects close to the antenna array.

ISSN:0950-0340    

DOI:10.1080/09500349014550101

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor