Abstract:
In a device for measuring the complete polarization state of light over a spectral bandwidth, an optical input signal (41) with wavelengths of light within a spectral band is incident on two or more diffraction gratings (42, 44, 46, 48), or incident from at least two directions on one or more diffraction gratings (72, 74), and the intensity is measured as a function of wavelength for at least four of the diffraction spectra produced by the grating(s). The polarization state of light is then calculated as a function of wavelength over the spectral bandwidth from the intensity measurements.
Abstract:
A single-layer ultrathin film and thin film are measured by setting a combination model of the film thickness, the optical constant using a dispersion formula, and the angle of incidence and by repeating fitting with the measured spectrum by the best local minimum calculation BLMC finite times. Similarly the thin-film n-layer n >= 2 structure is determined by setting combination models of two-layer structure and 3- to n-layer structures and by carrying out fitting by the best local minimum calculation BLMC and the extended best local minimum calculation EBLMC. By any measurement of the thin film being measured on a substrate, while varying thee wavelength of the incident light, the measurement spectrum &PSgr;Elambdi and DELTAElambdi representing the variations of polarization of the incident light and the reflected light for each waveform lambdi are determined. By the fitting with the measurement spectrum model, an optimum model is selected. The result of selection is checked, if necessary, and then stored.
Abstract:
The degree of polarization of an optical signal is measured by a polarimeter and used for providing a feedback signal to adjust adaptive optics of a polarization mode dispersion compensator. The polarization properties of the polarimeter are determined with high accuracy to match the polarimeter through calibration and used to produce the feedback signal.
Abstract:
Apparatus and methods for polarimetric measurements across a spectral range, such as determining the polarimetric state acrosS a wavelength band in a wavelength-division multiplexed fiber optic channel. A variable phase delay is introduced between orthogonal polarization components in an incident light. The resulting intensity changes are used to compute parameters indicative of the polarimetric state of the light. These measurements may be used, for example, for polarimetric imaging, polarimetric component characterization, and measuring polarization states in a fiber link.
Abstract:
A system and method for precisely measuring low-level and circular birefringence properties (retardance and direction) of optical materials (26). The system incorporates a photoelastic modulator (24) for modulating polarized light that is then directed through a sample (26). The beam ("Bi") propagating from the sample is separated into two parts, with one part ("B1") having a polarization direction different than the polarization direction of the other beam part ("B2"). These separate beam parts are then processed as distinct channels. Detection mechanisms (32, 50) associated with each channel detect the time varying light intensity corresponding to each of the two parts of the beam. This information is combined for calculating a precise measure of the linear and/or circular retardance induced by the sample, as well as the sample's fast axis orientation and direction of circular retardance.
Abstract:
The invention concerns a micropolarimeter comprising an analyzer (1) and a detector (10) located past the analyzer in the direction of radiation and presenting a number of segments ND which is higher than or equal to 3 (11). The invention seeks to provide a micropolarimeter with no moving parts, with a high polarization index, for use for polychromatic light, so small that it can detect the ray of common lasers in one single measurement step without it being necessary to enlarge it, and capable of being converted in a simple manner into a complete stokesmeter. To that end, the analyzer (1) consists of a radially symmetrical flat disk (5) produced in a polarizing material with which the polarization rests on absorption effects inside said material, the surface of the analyzer (1) being greater than or equal to the surface of the detector segments (10).
Abstract:
High pressure liquid chromatography apparatus for use in the analysis of optically-active materials comprises a semiconductor laser diode radiation source (10), a test sample holder (13) through which radiation from the radiation source passes to a detector (16). A polariser (11) and analyser (15) cooperate with a modulator (12) which modulates the rotation of the polarisation of radiation from the laser.