Searching for isovector signatures in the neutron-rich oxygen and calcium isotopes

We search for potential isovector signatures in the neutron-rich oxygen and calcium isotopes within the framework of a relativistic mean-field theory with an exact treatment of pairing correlations. To probe the isovector sector we calibrate a few relativistic density functionals using the same isoscalar constraints but with one differing isovector assumption. It is found that under certain conditions, the isotopic chain in oxygen can be made to terminate at the experimentally observed ${}^{24}$O isotope and in the case of the calcium isotopes at ${}^{60}$Ca. To produce such behavior, the resulting symmetry energy must be soft, with predicted values for the symmetry energy and its slope at saturation density being $J\!=\!(30.92\pm0.47)$ MeV and $L\!=\!(51.0\pm1.5)$ MeV, respectively. As a consequence, the neutron-skin thickness of ${}^{208}$Pb is rather small: $R_{\rm skin}^{208}\!=\!(0.161\pm0.011)$ fm. This same model - labelled "FSUGarnet" - predicts $R_{1.4}\!=\!(13.1\pm0.1)$ km for the radius of a "canonical" 1.4$M_{\odot}$ neutron star, yet is also able to support a two-solar-mass neutron star.Comment: 6 pages, 5 figure

An Overview of Ellipsometric Measurements for Nonplanar Surfaces

Ellipsometry is an optical method used for characterizing materials and thin films. The principle of ellipsometry is that it measures polarization changes at a sample in a reflection or transmission configuration. However, the shape of the sample is limited to flat or nearly flat surfaces because ellipsometry is sensitive to the angle of incidence, tilt angle and the sample position (height). Even slight misalignment of the sample might lead to significant experimental errors. For large misalignment, the detector of the ellipsometer is not feasible to receive sufficient signals. There have been a few approaches for characterizing nonplanr surfaces by ellipsometry. This report gives an overview of these approaches for ellipsometric measurements of nonplanar surfaces

An Overview of Return-Path Ellipsometry

Ellipsometry is an optical method used for characterizing materials and thin films. The principle is based on the polarization change at a sample due to the reflection or transmission at boundaries. By the measurement of the amplitude ratio Ψ and the phase difference Δ, the complex refractive index can be obtained. Ellipsometers can be used in various industries, e.g., semiconductor, chemistry, and display industry. The typical applications are quality control of film growth and defect inspection. In the configuration of return-path ellipsometry (RPE), the light beam is reflected twice from the sample. Thus, RPE has a higher sensitivity to the optical properties of samples. Some configurations of RPE have high tilt tolerance which is an important requirement for inline measurement. This report gives an introduction to the principle of ellipsometry and an overview of four different types of RPE

Characterization of Mueller matrices in retroreflexellipsometry

Ellipsometry is a widely-used technique for characterizing materials and thinfilms. The principle is based on the polarization changes after light is reflectedor transmitted at a sample. In general, the shape of the sample should be flat ornearly flat because ellipsometry is sensitive to the angle of incidence, tilt angleand the sample position (height variation). For nonplanar surfaces, retroreflexellipsometry was proposed to solve the problem of the alignment. Despite ofthe Mueller matrix, the coherency matrix is often used for depolarization andnoise reduction. In retroreflex ellipsometry, the measured Mueller matrix can beseen as a dual-rotation transformation. Therefore, it is important to discuss thechanges of reference frames for Mueller matrices. In this report, the polarizationmodel of retroreflex ellipsometry will be introduced. Decompositions andinvariant quantities of a Mueller matrix with a dual-rotation transformation willbe discussed