Noise in cavity enhanced spectroscopy due to higher order mode excitation in a resonant cavity is reduced. There are two main points. The first point is that the source and detector are both fiber coupled, to provide the spatial filtering and other general advantages of fiber coupling. The second point is that the cavity is designed to ensure sufficient separation in frequency between the desired TEM.sub.00 mode and the first few higher order spatial modes.

A method for analysing radiation emitted by the upper atmosphere, including the steps of collecting a beam coming from a direction (h, A) of the atmosphere, polarising the collected beam, selecting at least one frequency range of the collected beam and measuring an intensity of the at least one frequency range of the collected and polarised beam (I(θ,t)) according to the angle θ(t). The method includes the step of determining, from the values of I(θ,t) collected on a rotation of at least Π/2 radians of the variable angle polariser:—at least one physical and/or chemical and/or electromagnetic parameter of the upper atmosphere, and/or a variation of at least one physical and/or chemical and/or electromagnetic parameter of the upper atmosphere, and/or—a probability of malfunction and/or degradation of networks and/or electrical and/or electronic equipment and/or systems and/or devices.

Apparatus and methods for hyperspectral imaging analysis that assists in real and near-real time assessment of biological tissue condition, viability, and type, and monitoring the above overtime. Embodiments of the invention are particularly useful in surgery, clinical procedures, tissue assessment, diagnostic procedures, health monitoring, and medical evaluations, especially in the detection and treatment of cancer.

A method for phase contrasting-correlation spectroscopy: converting an incident linearly polarized light into two polarized components (polarized divergent and convergent components, wherein the polarized divergent component is orthogonal to the polarized convergent component), focusing each of the polarized divergent component and the polarized convergent component into a focal plane, thereby producing two focus planes constituting a reference focus (RF) plane and a sample focus (SF) plane; placing a sample at the SF plane and ambient conditions of the sample at the RF plane, resulting in a phase shift between the two polarized components; reconstituting the two phase-shifted polarized components into a phase-shifted linearly polarized light; detecting the phase-shifted linearly polarized light; calculating phase and intensity of the sample from the phase-shifted linearly polarized light; establishing an autocorrelation of phase and intensity of the phase-shifted linearly polarized light; and generating correlograms of intensity and phase of the phase-shifted linearly polarized light.

Reflected light detecting device and method with surface reflected light components collectively be extracted/removed when detecting reflected light arising in casting light onto target-object range having non-planar surface. The device includes: a first illuminating device causing first-measurement light in predetermined polarization direction to enter target-object first region from first direction; polarization optical system position part of first-surface reflected light enters the polarization optical system, the first-surface reflected light being the first-measurement in the first region surface; a second illuminating device causing second-measurement light in the same first-measurement light polarization direction to enter second region from second direction, the second region being on the target-object surface, different from the first region; adjusting direction of the second-measurement light optical axis so part of second-surface reflected light enters the polarization optical system, the second-surface reflected light being the second-measurement in second region surface; and detecting light having passed through the polarization optical system.

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.

A spectroscopic analysis apparatus includes: a light projecting device; a light receiving device; and an output device, wherein the light receiving device includes: a separator configured to separate reflected light into s-polarized light and p-polarized light; a detector for s-polarized light configured to output an electric signal indicating an intensity of the s-polarized light; and a detector for p-polarized light configured to output an electric signal indicating an intensity of the p-polarized light; and the output device is configured to: calculate an absorbance based on a ratio between the intensities of the s-polarized light and the p-polarized light using the electric signals output from the detector for s-polarized light and the detector for p-polarized light; and calculate either or both of the composition and the composition ratio of the surface of the measurement target object using an intensity of the absorbance at any desired wavenumber.

An image processing apparatus includes a corrector configured to provide a color correction based on a reference image selected from a plurality of color images having different polarization states acquired by changing a retardation provided to light from an object, for a synthesized image generated with polarization information of the object obtained from the plurality of color images.

We have invented an EUV spectroscopic polarimeter including a light receiving element, a first polarizing modulation element, a second polarizing modulation element, an energy splitting element and a light detecting and analyzing apparatus. The light receiving element is for receiving a target light. The first polarizing modulation element is rotatably connected to the light receiving element for generating a first polarized light. The second polarizing modulation element is rotatably connected to the first polarizing modulation element for generating a second polarized light. The energy splitting element receives the second polarized light so as to generate a modulated-polarization and energy-resolved light. The light detecting and analyzing apparatus receiving the polarization-modulated and energy-resolved light and providing a spectrum information by an analyzing algorithm which is able to retrieve the helicity, ellipticity, tilt angle and the degree of polarization for the whole spectrum of the target light.

In a system for analyzing optical properties of an object (350) a point source of light (100) composed of multiple spectral bands each having a respective amplitude, phase and polarization is converted by first optics (120, 150) into a line light source to illuminate an object line on the object. A beam splitter (200) splits the light exiting the first optics and directs a first portion of light on to the object (350) as an illuminated line and a second portion of the light on to a reference mirror (450). Second optics (500) collects respective first and second lines of light reflected by the object and mirror of and collinearly images the reflected lines of light as an image line on to an imaging spectrometer (550) wherein mutual interference allows determination of the optical properties of the object at each point along the object line.