Abstract: A display device includes: a color filter including a first transmissive filter, a second transmissive filter, and a third transmissive filter, the first, second and third transmissive filters being configured to transmit respective light beams having peak wavelengths different from each other; a first selective-wavelength-reflection layer adjacent to an optical-input surface of the first transmissive filter, the first selective-wavelength-reflection layer being configured to reflect light of a wavelength band that passes through the third transmissive filter; a second selective-wavelength-reflection layer adjacent to an optical-input surface of the second transmissive filter, the second selective-wavelength-reflection layer being configured to reflect light of a wavelength band that passes through the third transmissive filter, the second selective-wavelength-reflection layer being identical in composition to the first selective-wavelength-reflection layer; and a light emitter configured to emit light that t

Abstract: The wide-angle emission filter includes a base matrix, a photoresist, and a colorant. The base matrix has a flat shape and including a transparent material. The base matrix does not generate fluorescent light or phosphorescent light by an excitation light. The photoresist is disposed in the base matrix. The photoresist is fixed in a solid state through at least one method selected from the group consisting of thermal hardening, photo hardening, and drying. The colorant is disposed in the base matrix and includes light having a predetermined wavelength range. The wide-angle emission filter filters the excitation light regardless of an incident angle of the excitation light.

Abstract: Techniques and mechanisms for providing a tunable RF resonator device. In an embodiment, a patterned layer of an adhesive material is disposed on a side of a panel comprising a substrate and a metal layer. A membrane is aligned between the panel and another panel. A laminate is formed with the first panel, the second panel and the membrane, where an intermediate layer of the laminate includes a first portion comprising a liquid crystal channel, and a second portion comprising adhesive material disposed in interstices of the membrane. In another embodiment, the second portion forms at least part of a boundary to the liquid crystal channel.

Abstract: A polarizer includes a base substrate and a dielectric stacked layer. The dielectric stacked layer in includes a first dielectric layer and second dielectric layer. The first dielectric layer has a high refractive index and a second dielectric layer has a low refractive index. A wire grid pattern is disposed on the dielectric stacked layer. The wire grid pattern has a line width, a separation distance and a pitch. The pitch is a sum of the line width and the separation distance. Adjacent grids of the wire grid pattern are spaced apart by the separation distance.

Abstract: The invention relates to optical beam steering. There is described an optical beam steering apparatus, comprising: a splitter arranged to split an optical beam into at least a first part having a first polarization and a second part having a second polarization, said first and second polarizations being substantially mutually orthogonal; a first liquid crystal device region arranged to receive said first part and to have director orientation substantially aligned to said first polarization; and a second liquid crystal device region arranged to receive said second part and to have director orientation substantially aligned to said second polarization.

Abstract: The invention relates to a broad band continuous tunable laser. The laser includes a first laser cavity mirror, a laser gain medium, an intracavity collimating lens, an active optical phase modulator, a tunable acousto-optic filter, and the tunable laser further includes an intracavity reflection mirror to reflect the first order diffracted beam of the first diffraction back to the tunable acousto-optic filter to compensate the wavelength shift, a tunable Fabry-Perot filter arranged in the optical path of the second diffraction beam, a second laser cavity mirror and a laser drive and control circuit system. A stable laser output and the precision optical frequency tuning for less than 1 GHz frequency accuracy within a wide spectrum range can be realized. The invention is compact with stable performance, low cost for volume production and easy installation without moving parts.

Abstract: A hybrid tunable filter includes an upper substrate comprising an upper lip and a lower substrate comprising a lower lip, a first conductive layer coated on a lower surface of the upper substrate, a second conductive layer coated on an upper surface of the lower substrate, a first high reflectivity layer formed on a portion of the first conductive layer, a first electrode layer formed on a portion of the first conductive layer under the upper lip, a second high reflectivity layer formed on a portion of the second conductive layer, a second electrode layer formed on a portion of the second conductive layer above the lower lip, and a band-pass filter layer that can pass the etalon cavity to produce an output light having a single spectral peak.

Abstract: A method for controlling an electro-optic modulator device includes measuring a performance metric of the device to define a first measured performance value, and changing a state of a first tuning portion of the device to connect the first tuning portion to ground.

Abstract: Included is a light emitting unit, an optical deflector, a control unit, and a liquid crystal panel. The optical deflector includes a first optical deflector and a second optical deflector which are arranged side by side in a direction from a light incident side to a light emitting side. A maximum light deflection angle of the first optical deflector is smaller than a maximum light deflection angle of the second optical deflector, and a maximum light deflection speed of the first optical deflector is higher than a maximum light deflection speed of the second optical deflector. The first optical deflector includes a first optical deflection layer and a second optical deflection layer stacked in the direction from the light incident side to the light emitting side. Each of the first and second optical deflection layers includes the liquid crystal deflection elements arranged in the planar state.

Abstract: A light deflecting apparatus includes first and second light deflecting liquid crystal cells, each corresponding to each eye of a user and each comprising a liquid crystal layer including liquid crystal molecules with positive dielectric anisotropy and exhibiting a cholesteric blue phase when no voltage is applied, a pair of transparent substrates sandwiching the liquid crystal layer, a pair of transparent electrodes each being formed above each transparent substrate, a prism layer formed above one of the transparent substrates, and a driving device switching between a first state wherein the first and the second light deflecting liquid crystal cells are respectively in a homeotropic phase and a cholesteric blue phase, and a second state wherein the first and the second light deflecting liquid crystal cells are respectively in a cholesteric blue phase and a homeotropic phase.

Abstract: A cholesteric liquid crystal device is provided. The cholesteric liquid crystal device includes a first substrate, a second substrate disposed opposite to the first substrate, a first reflective layer disposed over the first substrate, a second reflective layer disposed over the second substrate, facing the first reflective layer, and a partition structure disposed between the first and the second substrates, wherein a cavity is formed by the partition structure, the first reflective layer and the second reflective layer, and a cholesteric liquid crystal layer is filled in the cavity.

Abstract: A reflective display device including: a substrate; a reflective layer on the substrate and configured to reflect light incident on the reflective layer; a color filter layer on the reflective layer; and an optical shutter layer on the color filter layer. Each pixel of a plurality of pixels of the reflective display device includes a plurality of sub-pixels and each sub-pixel includes the substrate, the reflective layer, the color filter layer, and the optical shutter layer, and for each pixel, the color filter layer includes a plurality of color filter elements corresponding to colors respectively obtained by the plurality of sub-pixels.

Abstract: A voltage-tuned optical filter that is low cost and simple to fabricate uses cascaded etalon modules, each module comprising a liquid crystal etalon, such as a Fabry-Perot etalon, having a relatively small Free Spectral Range (FSR). At least two of the modules are provided with a voltage control to enable Vernier tuning control. For a given overall scan, the voltage-tuned optical filter may operate with reduced voltage ranges for each liquid crystal etalon.

Abstract: A liquid crystal etalon includes a chiral nematic material contained in a liquid crystal cell having alignment surfaces configured to bias the chiral nematic material toward a twisted liquid crystal configuration with a twist less than 360°. Electrodes are arranged to apply an operative electrical bias to the liquid crystal cell. Mirrors disposed about the chiral nematic material define a resonant optical cavity. At a first electrical bias the etalon is transmissive for light of a first wavelength via a selected liquid crystal twist angle and cavity thickness at which different non-equal eigenmodes reach resonance conditions simultaneously. In a projector embodiment, a projection system with a field sequential image projection light source is coupled with the liquid crystal etalon, the etalon electrodes are patterned into pixels defining a display area, and the projector is operated in a field sequential illumination mode.

Abstract: A system and method for automated customer feedback allows for automatically collecting and analyzing customer feedback data regarding customer satisfaction and customer task completion with respect to self-service applications and live agents. When contacting a customer service center, customers provide one or more customer tasks. The customers are routed within the customer service center based on the customer task and/or one or more customer characteristics. While interacting with the customer service center, the customers are automatically asked one or more specific survey questions relating to the customers' interaction with the customer service center and the customers' satisfaction levels. The customers provide one or more survey responses to the survey questions. The survey responses are recorded and analyzed in order to modify and update the customer service center and the survey questions in order to increase customer satisfaction and increase customer task completion.

Abstract: A tunable laser has a gain material and a mirror defining an external resonant cavity. A tunable Fabry-Perot etalon disposed along the optical path between the mirror and the gain material includes a liquid crystal layer having a variable refractive index to tune the transmission peaks of the etalon and the resonant frequency of the laser resonant cavity. A second etalon having a fixed set of transmission peaks can also be included in the laser resonant cavity. The tunable etalon is then tuned to select a resonant frequency corresponding to one of the transmission peaks of the fixed etalon.

Abstract: A liquid crystal etalon includes a chiral nematic material contained in a liquid crystal cell having alignment surfaces configured to bias the chiral nematic material toward a twisted liquid crystal configuration with a twist less than 360°. Electrodes are arranged to apply an operative electrical bias to the liquid crystal cell. Mirrors disposed about the chiral nematic material define a resonant optical cavity. At a first electrical bias the etalon is transmissive for light of a first wavelength via a selected liquid crystal twist angle and cavity thickness at which different non-equal eigenmodes reach resonance conditions simultaneously. In a projector embodiment, a projection system with a field sequential image projection light source is coupled with the liquid crystal etalon, the etalon electrodes are patterned into pixels defining a display area, and the projector is operated in a field sequential illumination mode.

Abstract: Novel, polarization-insensitive, birefringent, broadband tunable filter arrangements that allow high throughput, based on a combination of tunable birefringent layers or polarization dependent filters, in combination with one or more of the following components (i) thin film achromatic quarter waveplates based on the form birefringence of dielectric subwavelength grating structures, (ii) nano wire-grid polarizers made of metallic wire grids; (iii) omnidirectional dielectric mirrors, (iv) polarization conversion mirrors, (v) reflective polarized beam splitters for circularly polarized light, (vi) metallic subwavelength gratings with lines having Gaussian profile, and (vii) Faraday mirror. All of these components may be implemented in thin film form on one or more substrates, such that a compact and cost effective filter can be produced. The birefringent layers can be any birefringent or magneto-optic layer but especially liquid crystals.

Abstract: An external cavity laser apparatus includes a wavelength tuning element mounted to a carrier on the apparatus's platform. Thermal control of the platform sets an initial position of the carrier and tuning element, from which independent tuning of the element can be achieved for wavelength tuning. The carrier is formed of a liquid crystal polymer that thermally isolates the tuning element from this platform, for such independent thermo-optical tuning. The liquid crystal polymer may match the coefficient of thermal expansion of the carrier to that of the platform. The support further includes embedded electrodes, either within or on the outer surface of the carrier, which can couple from the tuning element to the controller, where in some examples such coupling is direct and without use of additional electrical traces or wire bonds.

Abstract: A method of manufacturing a liquid crystal display device having good display quality, includes defoaming a liquid crystal composition having a mixture of liquid crystal and a polymerizable component to be polymerized by light or heat; dropping or transferring the liquid crystal composition onto one substrate; and attaching the one substrate and another substrate together in vacuum, and filling the liquid crystal composition therein by returning vacuum back to the atmospheric pressure. A polymerizing step polymerizes the polymerizable component.

Abstract: An external cavity laser apparatus includes a wavelength tuning element mounted to a carrier on the apparatus's platform. Thermal control of the platform sets an initial position of the carrier and tuning element, from which independent tuning of the element can be achieved for wavelength tuning. The carrier is formed of a liquid crystal polymer that thermally isolates the tuning element from this platform, for such independent thermo-optical tuning. The liquid crystal polymer may match the coefficient of thermal expansion of the carrier to that of the platform. The support further includes embedded electrodes, either within or on the outer surface of the carrier, which can couple from the tuning element to the controller, where in some examples such coupling is direct and without use of additional electrical traces or wire bonds.

Abstract: A two-way trans-reflective display pixel (100) having two viewable sides (102, 104) is disclosed. The two-way trans-reflective display pixel has a first transparent layer (106), a second transparent layer (108), and light modulating medium (110) sandwiched between them. Both the first and second transparent layers (106, 108) have light reflectors (132, 136) and light absorbers (130, 134), which allow light entering from either viewable sides (102, 104) to partially reflected, partially absorbed, and partially transmitted, allowing an image to be viewable from both viewable sides (102, 104). A two-way trans-reflective display (402) comprising a plurality of two-way trans-reflective display pixels (100) and a transparent light source (412) is also disclosed. The transparent light source (412) provides color light, and enables an image from the two-way trans-reflective display (402) to be viewable in color from both first and second viewable sizes (418, 602).

Abstract: A wavelength locker operates with a reference tunable liquid crystal filter having integrated photodetectors deposited on the front and backside of the liquid crystal cell to track power intensity of the accepted passband signal and its rejected signal compliment at a 50% power point where the two signals cross on the side of the filter transmission peak. The tunable filter is tuned by an offset wavelength from the laser wavelength such that 50% power is transmitted through the filter at the center wavelength of the laser. The wavelength locker may be configured with a liquid crystal tunable etalon or a liquid crystal tunable bandpass filter. A method for locking an optical signal to a desired frequency is also included and provides a substantially linear feedback signal computed by dividing the rejected signal power by the accepted signal power and passing it to laser transmitter to enable it to correct for frequency drift.

Abstract: A liquid crystal variable wavelength filter unit and its driving method applicable for a Wavelength Division Multiplexing (WDM) communication system and an optical network using an optical fiber. The liquid crystal variable wavelength filter unit (130) includes a band pass filter (111) configured of a dielectric multi-layered film inclined by a predetermined angle of ? between a first liquid crystal beam deflector (101) and a second liquid crystal beam deflector (103) and held between a first wedge prism (121) and a second wedge prism (123). The first drive device (141) is connected to the first liquid crystal beam deflector (101), and the second drive device (143) is connected to the second liquid crystal beam deflector (103). The wavelength is selected by the liquid crystal beam deflector by making the outgoing angle variable with respect to the band pass filter.

Abstract: A chiral structure having an advantageous extended chiral defect that provides an enhanced energy distribution characteristic therein. This is accomplished by configuring a central portion of the chiral structure with a pitch different from the rest of the structure. This may be envisioned as a distributed chiral twist with a predefined angle over a portion of a chiral structure. With the distributed defect, the photonic stop band remains wide, allowing for the substantial increase in the lifetime of the mode in which lasing occurs, while the extent of the high intensity region of the mode is large. The extended chiral defect structure may also be implemented as a thin-film chiral structure, for example using cholesteric liquid crystal or sculptured thin films.

Abstract: Thin film structures include electro-optic materials and transparent conducting materials which are combined to fabricate vertical optical devices. The electro-optic materials are responsive to an electric field to change an optical characteristic. For example, a modulator can be fabricated by making a dielectric mirror from such materials by alternating the electro-optic material with the transparent conducting material. The mirror reflection band can then be tuned by applying an electric field between the transparent conducting layers.

Abstract: A novel aspect to the invention is a structural arrangement to widen the Fabry-Perot gap beyond a 100-micron LC thickness. The widening permits greatly enhanced spectral discrimination (i.e. many more WDM channels) across the device response range, which is expanded to ITU standards by use of the twin etalon configuration. A liquid crystal optical multiplexer according to the present invention is a two-etalon Fabry-Perot laser etched into many (>100) sub-etalons in a rectangular array. Each sub-etalon is independently tunable and can be coupled to a distinct fiber. Any single sub-etalon or random combination of sub-etalons is free to be tuned to a particular wavelength corresponding to one of the input channels. This allows for any combination of signals (i.e digital video, data and voice) in a signal broadband channel to be switched to any of several receivers. Wavelength division multiplexing (WDM) is used to combine or separate individual types of signals from a single fiber.

Abstract: A tunable optical device includes a thin film device. The thin film device includes a plurality of cavities each including an electro-optic material. The electro-optic material includes an optical characteristic capable of being manipulated by application of an electric field. In this embodiment, at least some of the plurality of cavities are coherently coupled to others of the plurality of cavities. In this embodiment, the plurality of cavities include a sufficient number of cavities to result in an approximately square frequency response for the device.

Abstract: Methods for using a length dispersion of an etalon to approximate target resonant frequencies. Length dispersion usage in the present invention includes, for example, determining the impact of a length dispersion of an etalon on resonant frequencies of the etalon and may involve, for example, selection of one a more of a refractive index step, a number of layers, and a layer thickness of one or both dielectric stacks of the etalon in consideration of length dispersion. A featured method comprises defining target resonant frequencies and selecting an etalon having resonant frequencies which approximate the target resonant frequencies wherein the selection of the etalon is made based at least in part in consideration of a length dispersion of the etalon.

Abstract: Fabry-Perot etalons including a layer of liquid crystal between the reflective surfaces are disclosed. Application of an electric field to the liquid crystal layer changes the effective refractive index of the liquid crystal layer, making the device tunable.

Abstract: A polarization insensitive narrowband tunable filter utilizes an active liquid crystal cell to change the index of refraction and tuning of a waveguide resonant filter employing a nanostructured waveguide grating and polarization beam splitters to independently channel and convert S- and P-polarization states into optically and geometrically parallel beams which pass through the device. A multi-pixel configuration offers extended tuning range by employing a 1×N optical switch or splitter and N tunable pixel-filters each having offset center frequency enabling the tuning range of one pixel to partially overlap another pixel rendering the device and 1×N switch or splitter capable of scanning pixels to yield an expanded continuous tuning range mode.

Abstract: A tunable filter having a top mirror, a bottom mirror, and one or more intervening layers. The one or more intervening layers preferably have a refractive index that changes with temperature. By heating the one or more intervening layers, the wavelength that is selected by the optical filter can be controlled. The one or more intervening layers are preferably heated by passing current through the one or more intervening layers, or by passing current through a separate resistive layer that is thermally coupled to the one or more intervening layers. Such a filter can provide a high degree of wavelength selectivity in a robust and stable manner.

Abstract: A novel aspect of the invention is a structural arrangement to widen a Fabry-Perot gap beyond a 100-micron LC thickness. The widening permits greatly enhanced spectral discrimination (i.e. many more WDM channels) across the device response range, which is expanded to ITU standards by use of a twin etalon configuration. A liquid crystal optical multiplexer according to the present invention is a two-etalon Fabry-Perot laser etched into many (>100) sub-etalons in a rectangular array. Each sub-etalon is independently tunable and can be coupled to a distinct fiber. Any single sub-etalon or random combination of sub-etalons is free to be tuned to a particular wavelength corresponding to one of the input channels. This allows for any combination of signals (i.e. digital video, data and voice) in a signal broadband channel to be switched to any of several receivers. Wavelength division multiplexing (WDM) is used to combine or separate individual types of signals from a single fiber.

Abstract: An apparatus for filtering electromagnetic waves and sensing deposition of chemical species, the apparatus having a substrate having a surface relief structure containing at least one dielectric body with physical dimensions smaller than the wavelength of the filtered electromagnetic waves, such structures repeated in a two dimensional array covering at least a portion of the surface of the first substrate. The apparatus may include one, two, or more such arrays, spaced from one another to create one or more cavities between the arrays.

Abstract: A liquid crystal optical processor is configured in various applications, including a liquid crystal optical switch, polarization independent variable optical attenuator, wavelength selector switch, optical multiplexer and demultiplexer, tunable filter and flexible optical add drop multiplexer. The optical processor is generally configured to include a deposited metal gasket moisture barrier bonding two opposing substrates each having a spacer layer to accurately control cell gap thickness. The optical processor may be temperature insensative and be configured in one or more pixel configurations. The optical processor may include integrated subwavelength optical gratings. It may also include an integrated thermal sensor and heater deposition layer sandwiched between or deposited on at least one or both opposing substrates.

Abstract: An LC optical multiplexer according to the present invention is a two-etalon Fabry-Perot laser etched into many (>100) sub-etalons in a rectangular array. Each sub-etalon is independently tunable and can be coupled to a distinct fiber. Any single sub-etalon or random combination of sub-etalons is free to be tuned to a particular wavelength corresponding to one of the input channels. This allows for any combination of signals (i.e digital video, data and voice) in a signal broadband channel to be switched to any of several receivers. Wavelength division multiplexing (WDM) is used to combine or separate individual types of signals from a single fiber. Phase-matching coatings are used on the materials within the Fabry-Perot gap, thereby enhancing transmission performance of the WDM device. Mechanical techniques are used to widen the Fabry-Perot gap beyond a 100-micron LC thickness. The widening permits greatly enhanced spectral discrimination (i.e.

Abstract: Surface textures embossed in a substrate such as plastic include surface depressions or cones having equally-spaced, reflective terraced steps to support coherent reflections of incident light. A desired color or bandwidth of coherent reflected light off the terraced steps is produced by adjusting the index of refraction of a material in communication with the terraced steps of the substrate. Preferably, the index of refraction of each zone of terraced steps is controlled based on an applied electric field. Accordingly, light reflected from a plurality of controlled zones can be used to produce an image for an observer.

Abstract: An inclusion of the liquid crystal in the direct vicinity of the core of an optical waveguide structured on a substrate allows to build a tunable optical device. The liquid crystal will be confined by replacing cladding material of that integrated structure. The tuning of the property of that liquid crystal i.e. its refractive index will influence directly the mode index of the core. This influence can be of such amount to allow to control the flow of optical signals transmitted through it. The tuning is advantageously achieved by applying some electric field via electrode on a segment of that core confined with liquid crystals.

Abstract: An LC optical multiplexer according to the present invention is a two-etalon Fabry-Perot laser etched into many (>100) sub-etalons in a rectangular array. Each sub-etalon is independently tunable and can be coupled to a distinct fiber. Any single sub-etalon or random combination of sub-etalons is free to be tuned to a particular wavelength corresponding to one of the input channels. This allows for any combination of signals (i.e digital video, data and voice) in a signal broadband channel to be switched to any of several receivers. Wavelength division multiplexing (WDM) is used to combine or separate individual types of signals from a single fiber. Phase-matching coatings are used on the materials within the Fabry-Perot gap, thereby enhancing transmission performance of the WDM device. Mechanical techniques are used to widen the Fabry-Perot gap beyond a 100-micron LC thickness. The widening permits greatly enhanced spectral discrimination (i.e.

Abstract: There is provided a small and lightweight Fabry-Perot type optical tuner. By changing the distance between the reflector plates 3A and 3B with an applied voltage across said reflector plates 3A and 3B, wherein said reflector plates 3A, 3B are supported with coil springs 8A, 8B, and at the same time by changing the refractive index of the liquid crystal material 9, i.e. by utilizing both changes of distance d and refractive index n, an optical tuning can be obtained over a wide range of optical wavelength.

Abstract: An etalon has a first surface which is partially reflective. The reflectivity of the first surface varies with position. Thus, this reflectivity can in effect be adjusted by varying the point at which an optical beam is incident upon the etalon. At one point of incidence, the optical beam experiences one reflectivity. At a different point of incidence, the optical beam experiences a different reflectivity.

Abstract: A non-blocking N×N cross-connect is provided that has an array of liquid crystal (LC) switches in a grid of planar optical waveguides within a light optical circuit (LOC). LC filled trenches are used in a planar optical waveguide and each trench provides the functionality of a waveguide polarization splitter, a transverse electric (TE) switch cross point, a transverse magnetic (TM) switch cross point, or a waveguide polarization combiner. By combining these elements, a cross-connect system is fabricated.

Abstract: According to the present invention the tunable optical device comprises a first optical wave guide and a second optical wave guide defining a space between the two wave guides with space comprises the first cell with liquid crystal material and a second cell with liquid crystal material spaced by a third wave guide and the first and the second cell for liquid crystal material having orientation of the liquid crystal material perpendicular to each other.

Abstract: Fabry-Perot etalon type tunable wavelength-selective filter comprises: a first layer including a transparent electrode and an optical mirror layer; a third layer including a transparent electrode and an optical mirror layer; and a second layer which is composed of a material with a refractive index variable with electric field, and sandwiched between the first layer and the third layer, wherein the material having a refractive index variable with electric field is composed by dispersing liquid crystal droplets equal to or less than 150 nm in diameter in a light transmissive characteristic medium such as a polymer or silica glass, and by adding plasticizer therein. In this structure, the optical mirror layer consists of a dielectric multilayer mirror with an optical reflectance of equal to or more than 95% for 1.

Abstract: A method and system for filtering an optical signal is disclosed. The method and system comprise providing a polarization beam splitter, first and second rotators, a liquid crystal tunable filter, and first and second prisms. The polarization beam splitter splits the optical signal into two components based on polarization. The first rotator rotates a polarization 45 degrees in a first direction and is located between the liquid crystal tunable filter unit and the polarization beam splitter. The liquid crystal tunable filter unit includes liquid crystal molecules aligned 45 degrees clockwise relative to the vertical direction and is placed between the first rotator and the second rotator. The second rotator rotates the polarization 45 degrees opposite to the first direction. The first prism is located near the second rotator, while the second prism is near the beam splitter.

Abstract: A tunable Fabry-Perot filter, which includes a pair of opposed partially reflective surfaces, a cavity between the partially reflective surfaces, a nano-dispersion of liquid crystals disposed in the cavity, and a control unit for applying an electric field to the liquid crystals.

Abstract: An apparatus for filtering electromagnetic waves and sensing deposition of chemical species, the apparatus comprising a substrate having a surface relief structure containing at least one dielectric body with physical dimensions smaller than the wavelength of the filtered electromagnetic waves, such structures repeated in a two dimensional array covering at least a portion of the surface of the first substrate. The apparatus may include one, two, or more such arrays, spaced from one another to create one or more cavities between the arrays.

Abstract: An improved stepped etalon comprises a transparent body having a stepped surface. The lands of the steps are separated by a non-abrupt or softened transition region. This reduces the diffraction of light caused by the step transitions, thereby reducing the dead spot behind the step transition portions where interference prevents accurate measurements of light transmission from being made. Methods for producing a smoothly stepped etalon and for smoothing the step transitions in an abruptly stepped etalon are also disclosed.

Abstract: An LC optical multiplexer according to the present invention is a two-etalon Fabry-perot laser etched into many (>100) sub-etalons in a rectangular array. Each sub-etalon is independently tunable and can be coupled to a distinct fiber. Any single sub-etalon or random combination of sub-etalons is free to be tuned to a particular wavelength corresponding to one of the input channels. This allows for any combination of signals (i.e digital video, data and voice) in a signal broadband channel to be switched to any of several receivers. Wavelength division multiplexing (WDM) is used to combine or separate individual types of signals from a single fiber. Phase-matching coatings are used on the materials within the Fabry-perot gap, thereby enhancing transmission performance of the WDM device. Mechanical techniques are used to widen the Fabry-perot gap beyond a 100-micron LC thickness. The widening permits greatly enhanced spectral discrimination (i.e.

Abstract: A tunable filter in particular for use in the visible or near infrared wavelength region, comprising a nano dispersed composite material contained within a resonant cavity structure comprising dielectric mirrors (15, 16), where the material is polarizable by means of an applied electric field. In particular, the polarizable material may be a nano phase polymer dispersed liquid crystal (PDLC) material where the diameter of liquid crystal droplets (2) within the material (3) is less than 0.1 &mgr;m, and for use in the visible wavelength region is typically between 10 nm and 50 nm. The filter also comprises structure for applying a variable electric field across the faces of the material. The transmission-wavelength characteristic of the filter is such that maxima and minima are shifted in wavelength by varying the electric field.