Topic
Depolarization ratio
About: Depolarization ratio is a research topic. Over the lifetime, 968 publications have been published within this topic receiving 21162 citations.
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TL;DR: In this paper, the depolarization of light scattered from the beam of a helium-neon gas laser at low pressures was measured and the results of these measurements were reported.
Abstract: Measurements of the polarization of light scattered from the beam of a helium-neon gas laser at low pressures are described. The intensity, polarization and parallelism of the beam permit high accuracy, and new values for the depolarization ratios of twenty-four simple species are reported. The general quantum theory of scattering is discussed and applied in detail to the evaluation of a formula for the depolarization ratio of the scattered light. It is found that quantum corrections to the classical formula arise from ( i ) the effects of frequency changes due to rotational Raman scattering, ( ii ) changes in the molecular polarizability with rotational state due to centrifugal distortion, ( iii ) approximations inherent in the polarizability scattering formula, and ( iv ) vibrational Raman scattering. Effect ( i ) reduces the depolarization of hydrogen to 91% of its classical value; ( iii ) is unimportant unless the frequency of the light is near an absorption frequency of the molecule. The depolarization measurements have been combined with refractivity data to yield the anisotropies in molecular polarizabilities of the molecules studied.
579 citations
TL;DR: In this paper, the vertical profiles of the linear particle depolarization ratio of pure dust clouds were measured during the Saharan Mineral Dust Experiment (SAMUM) at Ouarzazate, Morocco, close to source regions in May-June 2006, with four lidar systems at four wavelengths (355, 532, 710 and 1064 nm).
Abstract: Vertical profiles of the linear particle depolarization ratio of pure dust clouds were measured during the Saharan Mineral Dust Experiment (SAMUM) at Ouarzazate, Morocco (30.9 ◦ N, –6.9 ◦ E), close to source regions in May–June 2006, with four lidar systems at four wavelengths (355, 532, 710 and 1064 nm). The intercomparison of the lidar systems is accompanied by a discussion of the different calibration methods, including a new, advanced method, and a detailed error analysis. Over the whole SAMUM periode pure dust layers show a mean linear particle depolarization ratio at 532 nm of 0.31, in the range between 0.27 and 0.35, with a mean Angstr¨ om exponent (AE, 440–870 nm) of 0.18 (range 0.04–0.34) and still high mean linear particle depolarization ratio between 0.21 and 0.25 during periods with aerosol optical thickness less than 0.1, with a mean AE of 0.76 (range 0.65–1.00), which represents a negative correlation of the linear particle depolarization ratio with the AE. A slight decrease of the linear particle depolarization ratio with wavelength was found between 532 and 1064 nm from 0.31 ± 0.03 to 0.27 ± 0.04.
482 citations
TL;DR: Strong polarization dependence is observed in the optical transmission through nanohole arrays in metals and the depolarization ratio shows a squared dependence on the aspect ratio of the holes, which is discussed in terms of coupling into and out of the surface plasmon modes.
Abstract: Strong polarization dependence is observed in the optical transmission through nanohole arrays in metals. It is shown that the degree of polarization is determined by the ellipticity and orientation of the holes; the polarization axis lies perpendicular to the broad edge of the ellipse. Furthermore, the depolarization ratio shows a squared dependence on the aspect ratio of the holes, which is discussed in terms of coupling into and out of the surface plasmon modes. The observed results will be useful for tailoring the polarization behavior of metallic nanophotonic elements in many applications, including surface plasmon enhanced optical sensing and ultrafast optical switching.
466 citations
TL;DR: In this article, the symmetry properties of the third-rank tensor β, which comprises the set of coefficients of quadratic terms in the expansion of the induced dipole moment in the electric field, are investigated, and various linear combinations belonging to the irreducible representations are tabulated for the important molecular symmetry groups.
Abstract: The symmetry properties of the third‐rank tensor β which comprises the set of coefficients of quadratic terms in the expansion of the induced‐dipole moment in the electric field are investigated, and the various linear combinations belonging to the irreducible representations are tabulated for the important molecular symmetry groups. Depolarization ratios are calculated for a sample composed of randomly oriented molecules (liquid phase). Examples of the selection rules in both liquid and crystalline phases are discussed, and these selection rules are contrasted with the ones appropriate for infrared absorption and the ordinary Raman effect.Molecular modes allowed in the infrared are always allowed in the hyper‐Raman effect and have a depolarization ratio (for linearly polarized incident radiation) ≤⅔, while allowed hyper‐Raman transitions forbidden in the infrared have a depolarization ratio of ⅔.
426 citations
TL;DR: In this article, the rotational Raman spectrum of water vapor and the measurement of the depolarization ratio for Rayleigh scattering from water vapor was found to be (3.0±1.4) ×10−4.
Abstract: This paper describes the observation and computer simulation of the rotational Raman spectrum of water vapor and the measurement of the depolarization ratio for Rayleigh scattering from water vapor, which was found to be (3.0±1.4) ×10−4. These results were combined with the value of the mean polarizability to calculate the principal polarizability components of the water molecule. At 514.5 nm, they are (in units of 10−24 cm3): αxx=1.468±0.003, αyy =1.415±0.013, and αzz=1.528±0.013, where the x axis is the dipole axis and the y axis is perpendicular to the molecular plane.
384 citations