Abstract: Apparatus for analyzing light having at least one wavelength, the apparatus comprising: (a) a light deflector for deflecting the light so as to provide a deflected light beam characterized by at least one wavelength-dependent angle, respectively corresponding to the at least one wavelength of the light; (b) an encoder, capable of encoding the deflected light beam so as to provide an encoded light beam characterized by at least one angle-dependent polarization state, respectively corresponding to the at least one wavelength-dependent angle; and (c) a decoder, for decoding the encoded light beam so as to determine at least one spectral component of the light.

Abstract: Methods for digitizing complex surfaces of dental objects such as impressions of dental surfaces and shapes. While an impression mold is being scanned by translation along a known trajectory, typically in a plane, the line of sight of a distance probe is directed toward successive positions on the surface of the impression mold, such as by a periodic series of reflecting surfaces characterized by normal vectors at distinct non-orthogonal angles with respect to their axis of symmetry. One or more reference objects are scanned using the same translation and mirror positioning systems. Gathered coordinate data are processed to apply angular corrections and combined to form a single distortion-corrected image of the impression mold. An apparatus and methods are provided for measuring both sides of a dental object separately, and then registering the two sides relative to each other in a digital representation of the object.

Abstract: A method and apparatus for accurately retrieving the position of an optical feature. The method uses the optical properties of biaxial crystals to conically refract the optical feature and transform the image of the optical feature to a circular ring structure. The position of the optical feature is then calculated by locating a center point associated with the circular ring structure.

Abstract: Apparatus for analyzing light having at least one wavelength, the apparatus comprising: (a) a light deflector for deflecting the light so as to provide a deflected light beam characterized by at least one wavelength-dependent angle, respectively corresponding to the at least one wavelength of the light; (b) an encoder, capable of encoding the deflected light beam so as to provide an encoded light beam characterized by at least one angle-dependent polarization state, respectively corresponding to the at least one wavelength-dependent angle; and (c) a decoder, for decoding the encoded light beam so as to determine at least one spectral component of the light.

Abstract: An optical transmitter, consisting of a radiation source which is adapted to generate a base optical beam with a base wavelength. The transmitter further consists of at least one modulator which is coupled to modulate the base optical beam so as to generate multiple carrier beams at respective side-bands of the base wavelength and to introduce information into the carrier beams for transmission thereby to a receiver.

Abstract: A method for division multiplexing of optical signals, the method including modulating at least one wavelength of a carrier of optical information, by optical frequency division multiplexing the at least one wavelength.

Abstract: An optical storage medium constitutes a substrate imprinted with optically detectable pits, each of the pits having one of a set of predetermined pit depths, each of the pits representing a number of binary bits corresponding to the number of the predetermined pit depths in the set. The pit depth is sensed unambiguously with a conoscopic holography sensor by changing the polarization of a polarized reflected beam in accordance with its angle of propagation and sensing an intensity pattern produced after the reflected beam passes through a polarized analyzer. Alternatively, using a confocal microscopy sensor, light from either the deepest or most shallow pit depth is focused on a small pin hole in an opaque surface, and a single detector measures the light intensity on the other side of the pin hole, the light intensity being a direct measure of the pit depth.

Abstract: The invention relates to a spatial light modulator device comprising a photo-refractive crystal addressed by means of a write light beam and a read light beam. The crystal is placed in the cavity of an interferometer system having a transmittivity-optical path length characteristic of steep slope so as to give rise to a dynamic range of maximum transmittivity variation for minimum variation in the refractive index or optical path length of the photo-refractive crystal. The device is applicable to conoscopic holography systems of large dynamic range and to pattern recognition in real time.

Abstract: A holographic apparatus of the type comprising a conoscopic system including a birefringent crystal inserted between two polarizers, wherein the apparatus also includes an aperture angle limiter inserted on the path of the light rays and wherein one of the birefringent crystal and the aperture angle limiter is disposed off the optical axis of the apparatus.

Abstract: A holographic method of the type implementing a conoscopic system including a birefrigent crystal inserted between two polarizers and a photosensitive element, wherein the method includes a step consisting in inserting one-dimensional optical means on the path of the light rays such that the conoscopic system only collects light that is parallel or quasi-parallel to a plane including the axis of the conoscopic system. The invention also provides apparatus for implementing the method.

Abstract: A method of generating a quasi-complex hologram using incoherent light and a conoscope system comprising a birefringent crystal (30) inserted between two circular polarizers (10, 20), the method comprising the following steps: (i) recording a plurality of different conoscopic holograms of the same object without relative displacement thereof and with respective different polarization configurations; and (ii) combining the various conoscopic holograms obtained in this way in order to remove the bias and the conjugate image. The invention also relates to a device for implementing the method.

Abstract: A hologram is recorded on a recording medium with polarized, monochromatic and incoherent light by passing the light from image points through an anisotropic medium and a polarization analyzer. A difference in phase retardation occurs for each of orthogonally polarized ordinary and extraordinary light waves which set up a transfer function of diffraction pattern at the film for recordation. The image can be reconstructed with monochromatic light passed back through the recording system, or with coherent light by illuminating the film directly to form the image on the opposite side at a position in space corresponding to the original point of the image recorded.