arXiv subjects
Publications and source records attributed to V. S. Zapasskii.
Using an experimental work on "stopped light" as an example, we show how a classical phenomenon of linear optics - interference of polarized light - can imitate the effect of electromagnetically induced transparency.
One-dimensional defect photonic crystal (Bragg waveguide) is studied from the viewpoint of the slow light problem. The calculations are presented showing that in the TiO$_2$/SiO$_2$-based Bragg waveguide one can obtain the group index of $\sim$ 1000 and spatial decay length of $\sim$ 3 mm for a nanosecond-scale pulse. Distortion of the pulse due to the group index dispersion proves to be acceptable for the relative pulse delay not exceeding 10. We also analyze propagation of the light pulse in the Bragg waveguide with a quantum well inside and provide arguments showing possibility of reaching the group index of $\sim$ 10000. To the best of our knowledge, analysis of pulse propagation in a Bragg waveguide in connection with the slow light problem has not been performed so far. We will still much appreciate any information about such studies, if any.
The question is raised about whether the pulse delay in a saturable absorber has anything to do with the "slow light" and group velocity reduction. We also wonder why the 40-years-old trivial interpretation of the effect remains so far ignored.
It is shown that the effect of hole-burning under conditions of coherent population oscillations as well as the light pulse delay in a saturable absorber (a modification of the "slow light" effect) can be interpreted, in a comprehensive way, in terms of {\it intensity spectrum} of the light and {\it intensity-related susceptibility} of the non-linear medium. The physical content of these effects is illustrated by a simple electric circuit with a non-linear resistor which realizes a full analog of the saturable absorber. In this case the effect of hole-burning in the absorption spectrum of the medium is converted in to the effect of hole-burning in the frequency dependence of resistance of the non-linear resistor and the effect of "slow light" -- in to the effect of "slow current".
A critical review of experimental studies of the so-called 'slow light' arising due to anomalously high steepness of the refractive index dispersion under conditions of electromagnetically induced transparency or coherent population oscillations is presented. It is shown that a considerable amount of experimental evidence for observation of the 'slow light' is not related to the low group velocity of light and can be easily interpreted in terms of a standard model of interaction of light with a saturable absorber.
The paper presents a critical analysis of publications devoted to one of the methods for production of the so-called "slow light" (the light with an anomalously low group velocity) due to extremely high local steepness of the dispersion curve of the medium. The method in point employs for this purpose the effect of coherent population oscillations accompanied by burning of a narrow spectral hole in the homogeneously broadened absorption spectrum. Physical model of the effect proposed in the studies under consideration is based on analysis of response of a nonlinear medium to a low-frequency intensity modulation of the incident light beam. We show that all the observations described in these papers can be easily interpreted in the framework of the simplest model of saturable absorber and have nothing to do with the effects of hole burning and group velocity reduction.
It is shown that the interpretation of the experimental results reported in the publication Storage of Light in Atomic Vapor" by D.F.Phillips et al., Phys. Rev.Lett. 86, 783 (2001) is incorrect. The experimental observation of this paper can be consistently explained in the framework of standard concepts of the physics of optical pumping and have nothing to do with "storage of light'', or "dynamic reduction of the group velocity'', or "light pulse compression''.
It is shown that the direct Fourier synthesization of light beams allows one to create polarity-asymmetric waves, which are able, in the process of nonlinear interaction with a medium, to break its inversion symmetry. As a result, these "polar" waves may show the effect of optical rectification in nonlinear centrosymmetric media by generating light-induced dc electric polarization. At the same time, the waves of this type, due to their unusual symmetry properties, can be used for detecting the direction and sign of a dc electric field applied to the medium. The prospects of application of polar waves to data recording and processing are discussed.