Search results for "Polarizer"

Phase Conjugation in BaTiO/sub 3/ Using Orthogonally Polarized Light Waves

2005

Transmission-line model to analyze a multistage polarizer rotator

1991

A simple transmission-line model to design a broadband system consisting of a multilayered polarization rotator that rotates the polarization plane of a linearly polarized electromagnetic wave is presented. A simulation program that permits the design of the rotator parameters was implemented, and a prototype was designed, manufactured, and tested. Comparisons between the theoretical results and measurements are given, and a good correspondence is found.

Fiber optical parametric polarizer

2013

In this work, a fiber-optical parametric polarizer (FOPP), i.e., a polarizing device based on parametric amplification in optical fibers is demonstrated. This was achieved for both the signal and idler waves with 25 dB gain over a broad bandwidth using the strong polarization-dependent gain (PDG) of parametric amplifiers. The experimental values of the degree of polarization (DOP) calculated from the Stokes parameters are indicated above each sphere. The gain spectra are also plotted with the parametric gain and the signal OSNR in insets. The Poincare sphere represents the three normalized Stokes parameters (S1,S2,S3) in unit radius. Results show that he DOP of the signal significantly incr…

Determination of absolute retardations by vectorial reconstruction

1977

In this paper is described the application of the vectorial reconstruction to the holographic determination of absolute retardation fringes. The method requires a double-exposure hologram recorded with two reference beams. During the reconstruction process the image emerging from the hologram is viewed through a linear polarizer. Where the polarization direction is parallel to one of the principal stresses, only the corresponding family of absolute retardations is observed. By rotating the polarizer it is possible to observe the fringes over the whole model. The method is demonstrated experimentally using a deep beam centrally loaded.

Measurement of three-dimensional mirror parameters by polarization imaging applied to catadioptric camera calibration

2008

International audience; We present a new efficient method for calibration of cata- dioptric sensors. The method is based on an accurate measurement of the three-dimensional parameters of the mirror through polariza- tion imaging. While inserting a rotating polarizer between the cam- era and the mirror, the system is automatically calibrated without any calibration patterns. Moreover, this method permits most of the constraints related to the calibration of catadioptric systems to be relaxed. We show that, contrary to our system, the traditional meth- ods of calibration are very sensitive to misalignment of the camera axis and the symmetry axis of the mirror. From the measurement of three-di…

Liquid/Gas and Liquid/Liquid Phase Equilibria of the System Water/Bovine Serum Albumin

2013

The thermodynamic behavior of the system H2O/BSA was studied at 25 °C within the entire composition range: vapor pressure measurements via head space sampling gas chromatography demonstrate that the attainment of equilibria takes more than one week. A miscibility gap was detected via turbidity and the coexisting phases were analyzed. At 6 °C the two phase region extends from ca. 34 to 40 wt % BSA; it shrinks upon heating. The polymer rich phase is locally ordered, as can be seen under the optical microscope using crossed polarizers. The Flory-Huggins theory turns out to be inappropriate for the modeling of experimental results. A phenomenological expression is employed which uses three adju…

Semi-automatic detection of skin malformations by analysis of spectral images

2013

The multi-spectral imaging technique to reveal skin malformations has been described in this work. Four spectral images taken at polarized monochromatic LED illumination (450nm, 545nm, 660nm and 940 nm) and polarized white LED light imaged by CMOS sensor via cross-oriented polarizing filter were analyzed to calculate chromophore maps. The algorithm based on skin color analysis and user-defined threshold selection allows highlighting of skin areas with predefined chromophore concentration semi-automatically. Preliminary results of clinical tests are presented.

Skin chromophore mapping by modified video-microscope

2013

Possibilities to map skin chromophores using a modified low-cost digital video-microscope is discussed. The device comprises CMOS digital imaging sensor, four-colour LED illumination system and image acquisition optics. The main goal is to obtain a set of spectral images of the skin area of interest for further conversion into maps of the main skin chromophores

A universal optical all-fiber omnipolarizer

2012

International audience; Wherever the polarization properties of a light beam are of concern, polarizers and polarizing beamsplitters (PBS) are indispensable devices in linear-, nonlinear- and quantum-optical schemes. By the very nature of their operation principle, transformation of incoming unpolarized or partially polarized beams through these devices introduces large intensity variations in the fully polarized outcoming beam(s). Such intensity fluctuations are often detrimental, particularly when light is post-processed by nonlinear crystals or other polarization-sensitive optic elements. Here we demonstrate the unexpected capability of light to self-organize its own state-of-polarizatio…