Determination of the 2D amplitude-phase structure of an optical field and the transfer function in the case of a convolution-like effect of a medium

A solution of the phase problem in optics as applied to the simultaneous detection and analysis of the phase-amplitude structure of image-forming or image-transmitting 2D optical fields and the phase-amplitude structure of probed media or objects, transfer or instrumental functions of signal-transmitting media, or field-or image-forming systems is considered. The effect of media or objects is described by the operation of convolution. The essence of the method applied is the introduction of two additional modulators, which in some way perform the function of visualizing the phase information. Optical schemes of two types are considered. In both cases, the first additional modulation precedes the action of a medium or an object. The second additional modulation takes place either in the plane immediately behind the probed medium (first type of scheme) or in the plane of spatial frequencies formed by the optical system (second type of scheme). In the first variant, the plane of detection is that of the spatial frequencies; in the second variant, it is the plane of the image formation. The resulting intensity distributions yield a solution to the problem.     

SU(3) symmetry operational approach to measuring amplitude and phase parameters for an optical field

We consider a new approach to the SU(3) symmetry polarization in Hilbert space for a quantum-optical Bose system with internal Gell-Mann symmetry. The operational determination of the SU(3) amplitude and phase characteristics for a three-mode optical field is discussed for the first time. An original twelve-port interferometer for simultaneous measurements of both the Gell-Mann and the phase parameters is proposed. The quantum properties of various W-class qutrit states under the measurement procedure for quantum information purposes are examined.     

Spectrum-modulation method for measuring the amplitude and phase characteristics of time-varying optical signals and transfer functions

The solution of the phase problem in optics, as applied to the determination of the amplitude and phase characteristics of optical signals varying in time and of the transfer functions of media transmitting the signals, is considered. The solution of this problem is based on using the spectrum-modulation method. In particular, the possibility of studying ultrashort processes is considered. The analysis was performed by probing the medium with an optical signal of an arbitrary structure. To obtain the information required, we used a four-channel optical arrangement with a spectral instrument, which records the intensity distributions directly for the signal under study after it passed through the medium; for the signal that was preliminary modulated in the specific manner and then passed through the medium; for the signal that was additionally modulated after passing through the medium; and for the signal that was additionally modulated both before and after passing through the medium. Each of these modulations should provide, to some extent, visualization of the phase information. Two variants of analysis were considered. In the first variant, the influence of the medium to be analyzed on the radiation considered is represented as modulation of the latter in time. The second variant is associated with studying the medium, whose influence on the signal brings about time-redistribution of the radiation and is described by a convolution operation.     

Spatial dependence of the dynamic optical transfer function of a transparent medium perturbed by an acoustic signal

Based on a spatially dependent (SD) dynamic optical transfer function (DOTF) of a medium perturbed by an acoustic signal, a dynamic theory has been developed of the acousto-optical interaction (AOI) of light beams in the field of an arbitrary acoustic signal under conditions of the diffraction distortion of its amplitude profile (DDAP). A system of integro-differential equations is derived for angular and frequency DOTF spectra of coupled waves in the AOI region. An analytical DOTF model has been constructed for a weak acousto-optical coupling. The characteristics of transient processes (TPs) in the diffracted-beam field have been investigated for the spatially dependent DOTF. It is demonstrated that in most practical situations this dependence is manifested rather strongly; however, it does not always affect the TP. Thus, when the light and acoustic beam apertures exceed some characteristic values d^* and L^*, related to the acoustic frequency and speed and the AOI geometry, the effect of the SD DOTF on the transient process can be neglected. Otherwise, the DDAP leads to the asymmetry of the dynamic dependences of the field amplitude of the off-axis angular-spectrum components of the diffracted beam. The parameters d^* and L^* have been calculated for the AOI of several types in lithium niobate and paratellurite crystals. The TP characteristics are illustrated by plots calculated for the DDAP in the case of the AOI in paratellurite. Tomsk State University of Control Systems and Electronics, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 40–48, May, 1999.     

Appliation of the limiting amplitude principle for field computation in a stratified medium

Institute of Applied Physics, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 32, No. 10, pp. 1265–1274, October, 1989.     

辐射传输介质散射相函数的蒙特卡洛算法

复分散系相函数在辐射介质传热中是关键参数,蒙特卡洛法兼具数值算法与试验测量的优点.利用该方法计算复分散系的多重散射相函数克服了以往算法的缺点,可以体现多重散射的影响,并且可以计算任意形状控制体的相函数.大量的数学实验发现当介质系密度增大时,散射能量在4π空间内分布趋于均匀.     

Optical transfer function of an optical system with a vortex phase mask in the presence of primary aberrations

The impact of primary aberrations on the optical transfer function of an optical system with a vortex phase mask has been investigated in detail. The optical transfer function of such a system becomes negative in a certain frequency range even in the absence of aberrations, a feature different from the case of an optical system in which center of the point spread function is bright.     

Characterizing individual scattering events by measuring the amplitude and phase of the electric field diffusing through a random medium

We describe observations of the amplitude and phase of an electric field diffusing through a three-dimensional random medium, using terahertz time-domain spectroscopy. These measurements are spatially resolved with a resolution smaller than the speckle spot size and temporally resolved with a resolution better than one optical cycle. By computing correlation functions between fields measured at different positions and with different temporal delays, it is possible to obtain information about individual scattering events experienced by the diffusing field. This represents a new method for characterizing a multiply scattered wave.     

Extension of depth of field using amplitude and phase modulation of the pupil function

We analyze the extension of depth of field using both amplitude and phase modulation of the pupil function. In particular, we discuss the advantages and disadvantages of each approach and establish the range of applicability of each method based on the range of spatial frequencies of interest in the imaging system. To the best of our knowledge, this is the first such report on the range of applicability of amplitude and phase modulation to extend the depth of field.     

A convenient representation for describing an electron in a uniform magnetic field

The newly established single-complex-variable state vector set for the two-dimensional harmonic oscillator in Fock space is generalized to describe an electron moving in a uniform magnetic field. In this formulation, the related Feynman transformation matrix elements are easily derived.     

The optical properties of a V-type atomic medium driven by an additional field

The effects of an additional level and field on the dispersion and absorption characteristics of a four-level atomic medium based on a V-type are studied. The steady state solutions are given under two different fourth level damping rate relations, with the tunable weak probing field and resonant coupling and driving fields.     

Optical bistability via amplitude and phase control of a microwave field

We investigate the steady-state optical bistability behavior in a three-level Λ-type atomic system closed by a microwave field under the condition that the applied fields are in resonance with corresponding atomic transitions. It is shown that the bistable hysteresis cycles can be controlled by both the amplitude and the phase of the microwave field.     

海洋与大气光学传递函数与自然光辐射场的关系

本文根据海洋辐射传递的变换模型确定海水光学传递函数与海中自然光场辐亮度分布的关系,分析了海中辐射场角频率谱变化。提出一种新的估算海中辐射场分布和测定海水光学传递函数的方法。这种方法完全适用于大气。     

Qualitative theory of amplitude and phase fluctuations in a medium with anisotropic turbulent irregularities

Abstract

Wave propagation in an anisotropic turbulent medium is studied assuming that the anisotropy coefficient η is constant for all scales of inhomogeneities. A qualitative method of studying the amplitude and phase fluctuations is developed. Formulae have been obtained for the phase structure functions and scintillation index for the medium with spectrum power index 3<μ<5 and anisotropy coefficient η≥1. Two particular cases have been studied in detail—propagation along and across the axis of the stretching of irregularities. During propagation along a short axis of inhomogeneities the fluctuations are decreasing and the phase structure function and scintillation index turn out to be η^μ?2 times smaller as compared with isotropic case. At the same time, during propagation along the long axis of inhomogeneities the phase structure function in vertical plane and the scintillation index are η times greater than in the isotropic medium.