Abstract:
The invention describes a method to eliminate instrumental offset in measurement of optically active scattering and circular dichroism. The method uses the time-average measurement of the light that is systematically transformed by series of optical devices. The optical devises perform the function of rotating linearly polarized light, interconventing left and right circular polarized light, converting circular polarized light to rotating linear polarized light and converting linear polarized light to alternating left and right circular polarized light.
Abstract:
The invention concerns a spectroscopic ellipsometer comprising a light source (1) emitting an optical beam, a polarizer (2) arranged on the path of the optical beam emitted by the light source, a sample holder (9) receiving the optical beam from the polarizer output, a polarisation analyser (3) designed to be traversed by the beam reflected by the sample to be analysed, a detection set which receives the beam from the analyser output and which comprises a monochromator (5) and a photodetector (4), means (6) for processing the signal in said detection set output, which include an electronic counter (13). Cooling means (12) maintain the detection set at a temperature lower than room temperature, minimising the noise of the detector so as to be constantly in the condition of minimum photon noise. The optimal measuring condition of the ellipsometer is reached by minimising all the sources of noise (lamps, detection, ambient noise).
Abstract:
A method for determining the composition of a target includes the steps of sensing radiation in the short wave infrared range scattered by the target area (50), measuring the polarization of the sensed radiation (52), and determining, from the polarization of the sensed radiation, the presence of at least one of water and ice particles in the target area (60).
Abstract:
A polarization state and polarization characteristics of a light transmitting medium are evaluated by Jones vectors containing Stokes vectors and Jones matrix. Rays of light of under three kinds of polarized states are applied from an incidence side apparatus (2) to a light transmitting medium (1), and a branched beam of light I on the outgoing side and branched beams of light Q, U and V passing through analyzers in directions of 0 DEG , 90 DEG and 45 DEG are detected as the Stokes vectors by light intensity. The Stokes vectors are normalized such as S1 = Q/I, S2 = U/I and S3 = V/I, and are re-normalized in a unit length such as S1/(S1 + S2 + S3 ) => S1. A polarization evaluation portion (15) actually measures the Jones vector containing the re-normalized Stokes vector as its component and evaluates the polarized state of the light transmitting medium (1). A polarization characteristics evaluation portion (13) actually measures a Jones matrix containing the re-normalized Stokes vector as the components thereof and evaluates the polarization characteristics of the light transmitting medium (1).
Abstract:
A polarization viewer comprising a mechanism (12, 18, 20) for forming a broadview image having a spectral width greater than 2 angstroms and 50 DEG based on polarization information of a scene. The polarization viewer is also comprised of a mechanism (12, 18, 20) for providing polarization information to the forming mechanism. The providing mechanism is in communication with the forming mechanism. In a first embodiment, the providing mechanism includes a camera mechanism in communication with the forming mechanism. The camera mechanism includes a fixed polarizer analyzer (12) disposed such that electromagnetic radiation entering the camera mechanism passes through the polarizer analyzer (12). The providing mechanism can also include a mechanism for steering a polarization plane of the radiation. The steering mechanism is disposed such that radiation passing through the polarizer analyser first passes through the steering mechanism. The steering mechanism preferably includes a first twist crystal (18) and at least a second twist crystal (20) aligned with the first twist crystal such that radiation passing through the first crystal has a first state and a second state.
Abstract:
In a optical detection system a plurality of photo-diode detectors are placed in an enclosure. The enclosure has an aperture through which is directed a light beam to be analysed. To eliminate the effect which ambient light entering the aperture would have one the detector signals, each of the detectors are arranged to be at equal distances from the aperture so that they all have the same acceptance cone angle for the light entering the aperture. Thus the ratio of signal to ambient light in the portion of the light beam reaching each detector is the same and the d.c. component of the signal produced by the detector can be easily removed in the signal conditioning electronics. The equal spacing of the detectors from the aperture is achieved in accordance with the invention by using beam splitters in the path of the beam to deflect portions of the beam to detectors which are offset from the beam axis.
Abstract:
This disclosure is generally directed to systems for imaging polarization properties of optical-material samples. As one aspect, there is provided a system for precise, simultaneous imaging of both the in-plane and out-of-plane birefringence properties of sample material over a wide range of incidence angles. The spatially resolved imaging approach described here is amenable to determination of a wide range of polarimetric properties, in addition to the inplane and out-of-plane birefringence measure discussed as a preferred embodiment.
Abstract:
A polarimetry apparatus comprising a plurality of flexible light conduits each having first and second ends, and a respective polarization modulator associated with each light conduit, wherein each light conduit is configured to receive incident light from a different predetermined region in space via the first end, and deliver said light to a detector unit via the second end, and wherein the polarization modulator is configured to modulate the polarization of the light to enable a partial or complete polarization state of the incident light to be determined by the detector unit for each light conduit.
Abstract:
An apparatus for separating polarization of light includes a rotatable beam splitter including an input for receiving light with a first polarization and an output for outputting light with a second polarization different from the first polarization. Rotation of the rotatable beam splitter changes the first polarization of the input light to the second polarization of the output light. An optical network and method are also set forth.
Abstract:
A device for enhancing transmission of incident electromagnetic radiation at a predetermined wavelength is presented that includes an aperture array structure in a thin film. The structure includes a repealing unit cell having more than one aperture including a first aperture and a second aperture, wherein a parameter of the first aperture differs from that of the second aperture. The unit cell repeats with a periodicity on the order of or less than said predetermined wavelength, The structure parameters are configured to preferentially support cavity modes for coupling to and enhancing transmission of a predetermined polarization state at the predetermined wavelength. By structuring the unit cell with apertures that differ by appropriate degrees in at least one of dimension, height, dielectric constant of material filling the apertures, shape, and orientation, the devices can be adapted for polarization and/or wavelength filtering- and/or light circulating, weaving, or channeling.