Abstract: Disclosed are various methods for creating optical elements through holographic fabrication. One method includes positioning a reflector in an optical path, disposing a first substrate proximal to the reflector along the optical path, disposing a first photosensitive film on the side of the first substrate facing the reflector, transmitting a light beam at a first polarization from a light source along the optical path, reflecting the light beam off the reflector, wherein the reflected light beam has a second polarization, receiving the reflected light beam through the first film and the first substrate, and applying a liquid crystal layer to the first photosensitive film to reproduce the alignment pattern of the first film on the liquid crystal layer.

Abstract: A multi-spectral lens comprises a circular polarizer and a tunable cholesteric filter having an associated reflection band. Incoming light is circularly polarized to one handedness by the circular polarizer, and the tunable cholesteric filter transmits the circularly polarized light and reflects the opposite handedness of the circularly polarized light if within the reflection band of the filter, with the reflection band of the tunable cholesteric filter varying with a control voltage. In a preferred embodiment, a mirror is arranged to receive light transmitted by the tunable cholesteric filter and reflect it back towards the filter with flipped handedness, with the reflected light with flipped handedness that is within the reflection band of the tunable cholesteric filter reflected by the tunable cholesteric filter back toward the mirror. The architecture described effectively converts the reflection band of a tunable cholesteric filter into a tunable bandpass filter for a multi-spectral imaging lens.

Abstract: A multi-spectral lens comprises a circular polarizer and a tunable cholesteric filter having an associated reflection band. Incoming light is circularly polarized to one handedness by the circular polarizer, and the tunable cholesteric filter transmits the circularly polarized light and reflects the opposite handedness of the circularly polarized light if within the reflection band of the filter, with the reflection band of the tunable cholesteric filter varying with a control voltage. In a preferred embodiment, a mirror is arranged to receive light transmitted by the tunable cholesteric filter and reflect it back towards the filter with flipped handedness, with the reflected light with flipped handedness that is within the reflection band of the tunable cholesteric filter reflected by the tunable cholesteric filter back toward the mirror. The architecture described effectively converts the reflection band of a tunable cholesteric filter into a tunable bandpass filter for a multi-spectral imaging lens.

Abstract: A method of fabricating a voltage-tunable liquid crystal-based notch filter requires filling at least two LC cells with cholesteric LC material to create LH and RH LC cells while applying heat to the cell substrates such that their temperatures are raised to near, but below, the clearing point, such that the LC material remains in the cholesteric state. An AC voltage is applied and turned off repeatedly while the LC cells cool down to room temperature, to cause the LC molecules to temporarily deviate from their intrinsic helical alignment. The cells are passed under a UV light sufficient to create cross-linked polymer networks, and self-compensation is used to compensate for in-band retardation. The resulting LH and RH LC cells are stacked such that the electrodes on adjacent substrates are connected to form a common electrode.

Abstract: A moving platform roll sensor system comprises an ellipsometric detector capable of detecting a polarized beam within the detector's line-of-sight, and measuring the beam's polarization state, such that the polarization state indicates the rotational orientation of the moving platform with respect to a predefined coordinate system. The ellipsometric detector comprises a venetian blind component through which the polarized beam passes, arranged such that the intensity of the exiting beam varies with its incident angle with respect to the moving platform, a polarizing beamsplitter which splits the exiting beam into components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of the beam, and first and second detectors which receive the first and second orthogonal circular components and generate respective outputs that vary with the intensities of their received components.

Abstract: A laser target board apparatus is provided for detecting spatial and temporal intensity distribution of high energy laser beams. The laser target board apparatus may include a panel having a plurality of openings and a plurality of optical rods placed therein. The laser target board apparatus may further have an optic fiber array positioned substantially parallel to and behind the panel and separated from the panel by a predetermined distance. At least one lens is configured to receive photons emitted from a second end of each optic fiber unit of the optic fiber array, and at least one camera is configured to detect the photons. A processor is configured to analyze temporal and spatial distribution of intensity of the received high energy laser beam based on data generated by the at least one camera.

Abstract: A moving platform roll sensor system comprises an ellipsometric detector capable of detecting a polarized beam within the detector's line-of-sight, and measuring the beam's polarization state, such that the polarization state indicates the rotational orientation of the moving platform with respect to a predefined coordinate system. The ellipsometric detector comprises a venetian blind component through which the polarized beam passes, arranged such that the intensity of the exiting beam varies with its incident angle with respect to the moving platform, a polarizing beamsplitter which splits the exiting beam into components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of the beam, and first and second detectors which receive the first and second orthogonal circular components and generate respective outputs that vary with the intensities of their received components.

Abstract: A method of fabricating large area birefringent grating films requires directing a UV beam through a large-scale LC polymer film alignment template on which a predetermined periodic alignment pattern has been imprinted and onto a photo-alignment layer such that the pattern is transferred thereon. The alignment template is fabricated by directing a collimated linearly polarized UV beam through a birefringent prism to produce two UV beams, which are directed onto a photo-alignment layer through a uniform quarter-wave plate to create a UV hologram which imprints the desired pattern onto the photo-alignment layer. These steps are repeated on different portions of the photo-alignment layer to create a large-scale photo-alignment layer.

Abstract: A laser target board apparatus is provided for detecting spatial and temporal intensity distribution of high energy laser beams. The laser target board apparatus may include a panel having a plurality of openings and a plurality of optical rods placed therein. The laser target board apparatus may further have an optic fiber array positioned substantially parallel to and behind the panel and separated from the panel by a predetermined distance. At least one lens is configured to receive photons emitted from a second end of each optic fiber unit of the optic fiber array, and at least one camera is configured to detect the photons. A processor is configured to analyze temporal and spatial distribution of intensity of the received high energy laser beam based on data generated by the at least one camera.

Abstract: The present invention relates to a method and apparatus to reduce dielectric discharge in liquid crystal cells driven with high voltage. In one embodiment, the present invention is a liquid crystal cell including a substrate with a surface and a tapered conductive film on top of the surface of the substrate including a first end and a second end. In another embodiment, the present invention is a method for forming a liquid crystal cell including covering a portion of a surface of a substrate with a shadow mask and then depositing conductive film onto the surface of the substrate such that the conductive film is tapered.

Abstract: A two-stage drive waveform switches a DFLC from a high tilt state to a low tilt state quickly and without scattering. A relaxation voltage is applied to delay the onset of the high amplitude high frequency kick voltage when switching from a high tilt state to a low tilt state. The relaxation voltage allows the molecules to ‘relax’ in accordance with their own elasticity towards their low tilt state in the direction of the average azimuth angle of the low tilt state. The kick voltage is then applied to drive the molecules quickly to the low tilt state. Optimal switching time and the desired molecular response is achieved by delaying the onset of the large kick voltage via application of the relaxation voltage. The relaxation voltage may constitute a lower amplitude holding voltage, a small or zero DC voltage or a smooth windowing of the kick voltage.

Abstract: This disclosure relates to a real-time, hybrid amplitude-time division polarimetric imaging camera used to derive and calculate Stokes parameters of input light.

Abstract: A two-stage drive waveform switches a DFLC from a high tilt state such as above the LC's linear region or near the ‘saturated’ or ‘field-driven homeotropic’ state of the LC to a low tilt state quickly and without scattering. A relaxation voltage is applied to delay the onset of the high amplitude high frequency kick voltage when switching from a high tilt state to a low tilt state. The relaxation voltage allows the molecules to ‘relax’ in accordance with their own elasticity towards their low tilt state in the direction of the average azimuth angle of the low tilt state. Once the tilt angle has relaxed sufficiently, the kick voltage is applied to drive the molecules quickly to the low tilt state. Most unexpectedly, optimal switching time and the desired molecular response is achieved by delaying the onset of the large kick voltage via application of the relaxation voltage.

Abstract: A liquid crystal based broadband filter and imaging system for analyzing the polarization state of radiation. The filter includes four elements: a quarter wave plate; a 45° polarization rotator; a 90° polarization rotator; and a fixed polarizer. The first three of these elements are electronically switchable, allowing the user to select from any of the six possible polarization states. The switchable elements use multiple liquid crystal cells made from dual-frequency materials. A dual-frequency signal is used to activate and deactivate the various elements to achieve the desired state configuration. The dual-frequency signal drives the liquid crystal cells in and out of states, improving the overall switching time of the filter. The configuration of the liquid crystal cells within each of the filter allows broadband operation over most of the visible, infrared and ultraviolet spectra. The filter cycles through six configurations corresponding to the six polarization states of the incident radiation.

Abstract: This disclosure relates to a real-time, hybrid amplitude-time division polarimetric imaging camera used to derive and calculate Stokes parameters of input light.

Abstract: The present invention relates to a method and apparatus to reduce dielectric discharge in liquid crystal cells driven with high voltage. In one embodiment, the present invention is a liquid crystal cell including a substrate with a surface and a tapered conductive film on top of the surface of the substrate including a first end and a second end. In another embodiment, the present invention is a method for forming a liquid crystal cell including covering a portion of a surface of a substrate with a shadow mask and then depositing conductive film onto the surface of the substrate such that the conductive film is tapered.

Abstract: A cadmium oxide (CdO) film doped with any of the Group III elements is substantially transparent to radiation between about 0.7 ?m and 12 ?m. A film made according to the invention having a sheet resistance of <600?/? will also have exceptionally low optical absorption throughout the IR range. The film is suitably employed as transparent, electrically conductive electrodes, and can be used in devices such as liquid crystal cells for beam steering, spatial light modulators, optical switches for fiber optical communications, switchable and/or tunable polarization modification components, and top transparent electrodes for SWIR (1.3 and 1.5 ?m) VCSELs.

Abstract: A spatial light modulator has a transmissive window with a transparent conductive film forming a ground plane and a direct drive backplane with a plurality of voltage gradient pixels. Each of the voltage gradient pixels has (a) resistive film, (b) resistive metal conductor frame on a boundary of the resistive film, and (c) conductive metal leads between a substrate of the direct drive backplane and the resistive metal frame. Differential voltages applied to the metal frame via the conductive metal leads generate a selective two-dimensional linear voltage gradient across the resistive film. A layer of liquid crystal material is disposed between the transmissive window and the voltage gradient pixels. Liquid crystal material of each voltage gradient pixel is responsive to an electric field generated by the voltage gradient to two-dimensionally alter phase of a wavefront incident thereon.

Abstract: An optical fiber coupling, for example, an optical switch, for coupling a light source with a light-receiving end face of an optical waveguide comprises a lens for focusing a light beam emitted from the light source at a focal point on the light-receiving end face of the optical waveguide. An adaptive coupler positioned in the optical path is responsive to a beam steering control signal for steering and aligning the focal point relative to the light-receiving end face of the optical waveguide.

Abstract: A spatial light modulator has a transmissive window with a transparent conductive film forming a ground plane and a direct drive backplane with a plurality of voltage gradient pixels. Each of the voltage gradient pixels has (a) resistive film, (b) resistive metal conductor frame on a boundary of the resistive film, and (c) conductive metal leads between a substrate of the direct drive backplane and the resistive metal frame. Differential voltages applied to the metal frame via the conductive metal leads generate a selective two-dimensional linear voltage gradient across the resistive film. A layer of liquid crystal material is disposed between the transmissive window and the voltage gradient pixels. Liquid crystal material of each voltage gradient pixel is responsive to an electric field generated by the voltage gradient to two-dimensionally alter phase of a wavefront incident thereon.