Abstract: The objective of the present invention is providing a method for fabricating high quality diffractive waveplates and their arrays that exhibit high diffraction efficiency over large area, the method being capable of inexpensive large volume production. The method uses a polarization converter for converting the polarization of generally non-monochromatic and partially coherent input light beam into a pattern of periodic spatial modulation at the output of said polarization converter. A substrate carrying a photoalignment layer is exposed to said polarization modulation pattern and is coated subsequently with a liquid crystalline material. The high quality diffractive waveplates of the present invention are obtained when the exposure time of said photoalignment layer exceeds by generally an order of magnitude the time period that would be sufficient for producing homogeneous orientation of liquid crystalline materials brought in contact with said photoalignment layer.

Abstract: The objective of the present invention is providing optical systems for controlling with propagation of light beams in lateral and angular space, and through optical apertures. Said light beams include laser beams as well as beams with wide spectrum of wavelengths and large divergence angles. Said optical systems are based on combination of diffractive waveplates with diffractive properties that can be controlled with the aid of external stimuli such as electrical fields, temperature, optical beams and mechanical means.

Abstract: The objective of the present invention is providing autonomous timing labels for indicating the aging and expiration of a time period of products through gradual changing of their color. The color change can be coded to run, for example, from blue for newly produced products to red with product aging thus allowing easy monitoring, quick identification, and visual warning when the elapsed time approaches and reaches the recommended or safe use time. Said labels comprise thin films of photonic bandgap materials such as cholesteric liquid crystals containing photoisomerizable molecules that are transformed into the state of isomers possessing with finite lifetime with the aid of exposure of the material to UV light. The change of the reflection wavelength of the photonic bandgap material takes place according to changing concentration of said isomers as a result of spontaneous relaxation to their equilibrium state. Said labels can be reused by UV light exposure.

Abstract: Non-mechanical optical beam steering and switching is produced by optically controlled liquid crystal spatial light modulator with angular magnification by high efficiency volume Bragg gratings recorded in a photosensitive PTR glass. Small angle beam deflection in a photoactive liquid crystal cell is produced by exposing it to a controlling beam from an external source of radiation with predetermined distribution of power density which causes predetermined spatial gradients of a refractive index in a liquid crystal cell and, therefore, refraction of a controlled beam which is made to propagate in the region with spatial gradient of the refractive index. Large angle beam deflection is produced by a volume Bragg grating with angular selectivity adjusted in such way that small angle scanning produced by optically controlled liquid crystal spatial light modulator results in change of diffraction efficiency from zero to 100% for switching the beam for two Bragg angles.

Abstract: The objective of the present invention is to provide means for reversibly controlling the shape of a polymer with a single light beam of low power density, inducing large range of polymer deformation angles, both positive and negative, at high speed, and at room temperature. The invention relates to variable optical components such as variable focus mirrors, lenses, light deflectors, shutters, attenuators, switches, and to remotely operated mechanical actuators.

Abstract: The objective of the present invention is providing a method and ultra light-weight instruments for controlling propagation of high energy laser beams. The control optical systems are based on gases and techniques for creating gas concentration and flow patterns that modulate the refractive index along the path of propagation of a laser beam.

Abstract: The objective of the present invention is providing a mechanical holder that allows optical filters, wave plates, and substrates of different shapes, sizes, and thickness to be simply, conveniently, flexibly, and quickly mounted, fixed and interchanged. This is achieved using grooved plates combined into a split-V-shaped configuration with variable separation and angle between the plates.

Abstract: The objective of the present invention is providing a method and a simple instrument that can be used on a routine basis to accurately and quickly measure the focus position, waist radius, divergence, quality, power and power density of a laser beam. The measurement is performed by scanning a thin film of a nonlinear optical material in the focal region along the propagation direction of the beam and registering the variation of the on-axis intensity of the laser beam by a photodetector.

Abstract: The objective of the present invention is providing a method and a simple instrument that can be used on a routine basis to accurately and quickly measure the focus position, waist radius, divergence, quality, power and power density of a laser beam. The measurement is performed by scanning a thin film of a nonlinear optical material in the focal region along the propagation direction of the beam and registering the variation of the on-axis intensity of the laser beam by a photodetector.

Abstract: Power density profile of a laser beam is characterized by scanning a thin thread across the beam and registering the intensity of radiation scattered from the thread. The diameter of the beam along the scan direction is determined by measuring the width of the signal received from the scattered power for the given speed of the thread across the beam.

Abstract: Meters detect power parameter information about laser beams using liquid crystals to propagate the beam therethrough with photodiode detectors. The power parameters include intensity in watts per square meter, beam waist size, and the location of the focal spot based in light induced orientational phenomena in the liquid crystal. The detectors can can count the number of interference fringe rings produced by a laser beam passing through the liquid crystal(LC). Alternatively, the time between the occurrence of each interference fringe ring can be measured to determine the power parameters. A preferred embodiment has a standard liquid crystal oriented at approximately 45 degrees to the axis of an incoming laser beam to be measured. The beam passing through the LC can be centered through a pinhole on a planar plate causing the interference fringe rings to appear on the surface of the plate. An alternative embodiment measures intensity based on determining the voltage necessary to produce fringe ring patterns.