1,251 research outputs found
Demonstration of an optical polarization magnifier with low birefringence
In any polarimetric measurement technique, enhancing the laser polarization
change of a laser beam before it reaches the analyzer can help in improving the
sensitivity. This can be performed using an optical component having a large
linear dichroism, the enhancement factor being equal to the square root of the
ratio of the two transmission factors. A pile of parallel plates at Brewster
incidence looks appropriate for realizing such a polarization magnifier. In
this paper, we address the problem raised by the interference in the plates and
between the plates, which affects the measurement by giving rise to
birefringence. We demonstrate that wedged plates provide a convenient and
efficient way to avoid this interference. We have implemented and characterized
devices with 4 and 6 wedged plates at Brewster incidence which have led to a
decisive improvement of the signal to noise ratio in our ongoing Parity
Violation measurement.Comment: 08 october 200
The language of Einstein spoken by optical instruments
Einstein had to learn the mathematics of Lorentz transformations in order to
complete his covariant formulation of Maxwell's equations. The mathematics of
Lorentz transformations, called the Lorentz group, continues playing its
important role in optical sciences. It is the basic mathematical language for
coherent and squeezed states. It is noted that the six-parameter Lorentz group
can be represented by two-by-two matrices. Since the beam transfer matrices in
ray optics is largely based on two-by-two matrices or matrices, the
Lorentz group is bound to be the basic language for ray optics, including
polarization optics, interferometers, lens optics, multilayer optics, and the
Poincar\'e sphere. Because the group of Lorentz transformations and ray optics
are based on the same two-by-two matrix formalism, ray optics can perform
mathematical operations which correspond to transformations in special
relativity. It is shown, in particular, that one-lens optics provides a
mathematical basis for unifying the internal space-time symmetries of massive
and massless particles in the Lorentz-covariant world.Comment: LaTex 8 pages, presented at the 10th International Conference on
Quantum Optics (Minsk, Belarus, May-June 2004), to be published in the
proceeding
Fresnel coefficients as hyperbolic rotations
We describe the action of a plane interface between two semi-infinite media
in terms of a transfer matrix. We find a remarkably simple factorization of
this matrix, which enables us to express the Fresnel coefficients as a
hyperbolic rotation.Comment: 6 pages, 3 figure
Experimental determination of the degree of quantum polarisation of continuous variable states
We demonstrate excitation-manifold resolved polarisation characterisation of
continuous-variable (CV) quantum states. In contrast to traditional
characterisation of polarisation that is based on the Stokes parameters, we
experimentally determine the Stokes vector of each excitation manifold
separately. Only for states with a given photon number does the methods
coincide. For states with an indeterminate photon number, for example Gaussian
states, the employed method gives a richer and more accurate description. We
apply the method both in theory and in experiment to some common states to
demonstrate its advantages.Comment: 5 page
Spectroscopic distinction between the normal state pseudogap and the superconducting gap of cuprate high T_{c} superconductors
We report on broad-band infrared ellipsometry measurements of the c-axis
conductivity of underdoped RBa_{2}Cu_{3}O_{7-d} (R=Y, Nd, and La) single
crystals. Our data provide a detailed account of the spectral weight (SW)
redistributions due to the normal state pseudogap (PG) and the superconducting
(SC) gap. They show that these phenomena involve different energy scales,
exhibit distinct doping dependencies and thus are likely of different origin.
In particular, the SW redistribution in the PG state closely resembles the one
of a conventional charge- or spin density wave (CDW or SDW) system.Comment: 4 pages, 4 figure
Iwasawa Effects in Multi-layer Optics
There are many two-by-two matrices in layer optics. It is shown that they can
be formulated in terms of a three-parameter group whose algebraic property is
the same as the group of Lorentz transformations in a space with two space-like
and one time-like dimensions, or the group which is a standard
theoretical tool in optics. Among the interesting mathematical properties of
this group, the Iwasawa decomposition drastically simplifies the matrix algebra
under certain conditions, and leads to a concise expression for the S-matrix
for transmitted and reflected rays. It is shown that the Iwasawa effect can be
observed in multi-layer optics, and a sample calculation of the S-matrix is
given.Comment: RevTex 10 pages including 1 psfi
Osteoma Cutis Associated with Nevus Sebaceus: Case Report and Review of Cutaneous Osteoma-associated Skin Tumors (COASTs)
Osteoma cutis is a benign cutaneous lesion characterized by the presence of bone within the dermis or subcutaneous fat. It most often develops in association with other skin lesions such as cutaneous tumors. Nevus sebaceus is a benign hamartoma of the skin that is composed of epidermal and dermal components. It most commonly appears on the scalp and may give rise to either benign or malignant secondary neoplasms. The clinical and pathologic features of a 36-year-old man with a nevus sebaceus and associated osteoma cutis are described. In addition, osteoma cutis-associated neoplasms are reviewed. Secondary osteoma cutis has been observed with both benign and malignant neoplasms as well as various non-neoplastic skin conditions. However, to the best of our knowledge, osteoma cutis has not previously been described in association with nevus sebaceus. Nevus sebaceus can now be added to the list of cutaneous osteoma-associated skin tumors (COASTs)
MARVEL analysis of high-resolution rovibrational spectra of ÂčÂłCÂčâ¶Oâ
A set of empirical rovibrational energy levels, obtained through the MARVEL
(measured active rotational-vibrational energy levels) procedure, is presented for the
13C16O2 isotopologue of carbon dioxide. This procedure begins with the collection
and analysis of experimental rovibrational transitions from the literature, allowing for
a comprehensive review of the literature on the high-resolution spectroscopy of
13C16O2, which is also presented. A total of 60 sources out of more than 750 checked
provided 14,101 uniquely measured and assigned rovibrational transitions in
the wavenumber range of 579â13,735 cm-1. This is followed by a weighted leastsquares refinement yielding the energy levels of the states involved in the measured
transitions. Altogether 6318 empirical rovibrational energies have been determined
for 13C16O2. Finally, estimates have been given for the uncertainties of the empirical
energies, based on the experimental uncertainties of the transitions. The detailed
analysis of the lines and the spectroscopic network built from them, as well as the
uncertainty estimates, all serve to pinpoint possible errors in the experimental data,
such as typos, misassignment of quantum numbers, and misidentifications. Errors
found in the literature data were corrected before including them in the final
MARVEL dataset and analysi
Polarization resolved angular patterns in nematic liquid crystal cells
We study the angular structure of polarization of light transmitted through a
nematic liquid crystal (NLC) cell by theoretically analyzing the polarization
state as a function of the incidence angles. For a uniformly aligned NLC cell,
the matrix formalism and the orthogonality relations are used to
derive the analytical expressions for the transmission and reflection matrices.
The polarization resolved angular patterns in the two-dimensional projection
plane are characterized in terms of the polarization singularities: C points
(points of circular polarization) and L lines (lines of linear polarization).
In the case of linearly polarized plane waves incident on the homeotropically
aligned cell, we present the results of detailed theoretical analysis
describing the structure of the polarization singularities. We apply the theory
to compute the polarization patterns for various orientational structures in
the NLC cell and discuss the effects induced by the director orientation and
biaxiality.Comment: pdflatex, rextex4, 22 pages, 7 figures (jpeg
Low-temperature far-infrared ellipsometry of convergent beam
Development of an ellipsometry to the case of a coherent far infrared
irradiation, low temperatures and small samples is described, including a
decision of the direct and inverse problems of the convergent beam ellipsometry
for an arbitrary wavelength, measurement technique and a compensating
orientation of cryostat windows. Experimental results are presented: for a gold
film and UBe13 single crystal at room temperature (lambda=119 um), temperature
dependencies of the complex dielectric function of SrTiO3 (lambda=119, 84 and
28 um) and of YBa2Cu3O7-delta ceramic (lambda=119 um).Comment: 14 pages, 6 figure
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