WO2017035092A1

WO2017035092A1 - Holographic optical angular compensator and systems and methods for making and using a holographic optical angular compensator

Info

Publication number: WO2017035092A1
Application number: PCT/US2016/048077
Authority: WO
Inventors: Gor SARKISYAN
Original assignee: Holographic Solar Partners, Llc
Priority date: 2015-08-23
Filing date: 2016-08-22
Publication date: 2017-03-02

Abstract

A duplex holographic optical element with imbedded passive tracking for static collection of light from its source with multiple applications in, for example, solar power generation and communications. A first holographic plate is produced with desired characteristics using a repetitive recording method, which in turn is used to generate a second holographic plate. The second holographic plate is then used to generate a holographic optical angular compensator that accepts signals from variable angles of incidence and transmits or reflects the signal in a predefined angle and direction.

Description

Title: HOLOGRAPHIC OPTICAL ANGULAR COMPENSATOR AND SYSTEMS AND METHODS FOR MAKING AND USING A HOLOGRAPHIC OPTICAL ANGULAR COMPENSATOR

Cross Reference to Related Applications

[0001 ] This application claims the benefit of U.S. Prov. Pat, App. No. 62/208,784 filed on August 23, 2015, the entirety of which is hereby incorporated by reference.

Background of the Invention

[0002] Field of the invention: This invention relates to the general field of optics and more specifically toward a duplex holographic optical element with imbedded passive tracking for static collection of light from its source with multiple applications in, for example, solar power generation and communications. A hologram is recorded with desired characteristics using a repetitive recording method, which in turn is used to generate a second hologram. The subsequent generation is then used to generate a holographic optical angular compensator that accepts signals from variable angles of incidence and transmits or reflects the signal in a predefined angle and direction.

[0003] Embodiments explained and described herein utilize new holographic techniques of producing a holographic optical angular compensator (HO AC). The HOAC is a holographic optical device that accepts electromagnetic signals from variable directions and/or angles of incidence and transmits or reflects the signal in a predefined angle.

[0004] Holographic optical elements are made by recording the interference patterns of two or more mutually coherent light sources in photosensitive material including, but not limited to: di photopoiymers, inorganic and organic photorefractive materials, dichromatic gelatin, silver halides, photoresists, sol-gel glasses, and thermoplastic, photochromic, photodichroic materials, and polychromatic gels functionally oriented passively or actively to a light source or source of radiati on to allow for multiple incidence angles of attack of direction of radiation and to allow concentrating reflective or transmission foci from ultra-short, such as nanometers to infinity. The holographic optical elements may be functionally configured as layers of structural medium such as silicon chips. [0005] Many optical devices are made to operate at a certain optical axis in order to function properly, regardless of the final output of the device therein used. For many applications this entails physically moving the device to keep the source of the light signal aligned with the device's optical axis. Incorporating a HO AC as a functional unit of an optical system thus allows passively receiving signals correctly aligned through the optical axis of an optical device without the need to move or adjust the device. The HOAC compensates for variable angle of incidence from a signal source, stationary or moving, so long as it is within a predefined angular window of operation of the passive holographic tracking domain enabling gap-free or near gap- free passive tracking.

[0006] Thus, it is desirable to have a holographic optical angular compensator device, system, and method for concentrating, reflectively or transmi ssibly, radiation incident from multiple, variable angles of attack to a focus that is near or far away from holographic optical angular compensator.

Summary of the Invention

[0007] The current disclosure provides a duplex holographic optical element with imbedded passive tracking for static concentration of light from its source with multiple applications in, for example, solar power generation and communications. A first holographic plate is produced with desired characteristics using a repetitive recording method, which in turn is used to generate a second holographic plate. This process may be repeated "n" times to produce an "nth" generation holographic plate. The nth generation holographic plate is then used to generate a holographic optical angular compensator that accepts signals from variable angles of incidence and transmits or reflects the signal in a predefined angle and direction.

[0008] Particular embodiments of the current disclosure relate to optical concentrators utilizing holographic optical systems in which, the holographic system receives optical signals from a predefined tracking domain in both X and Y axis, and at angles deviated from the normal axis while reflecting and/or transmitting in a predefined angle in relation to the plane of the hologram. A HOAC may simultaneously and passively have transmission elements along with reflective elements, or alternatively, have implement transmission and reflection separately. These variations can be spectrally selected for transmission of one spectral domain and reflection for another and/or transmission in certain angular domains and reflection in others. Further embodiments provide for a duplex holographic optical angular compensator (dHOAC) having simultaneous, concurrent or parallel functions of transmission and reflection of light.

Alternatively, the dHOAC has antecedent or subsequent functions of transmission or reflection of radiation, or a series of transmission or reflection of radiation.

[0009] Embodiments of the current disclosure provide for holographic optical elements as passive tracking for single or dual functional purposes, where these holographic optical elements utilize multilayer holographic recording film. Each layer is separately used for concentrating reflection, transmission, or both. A particular embodiment may have layers sensitized to different coherent light sources allowing direct recording of both transmission and reflection holograms to perform complex multiplexing. Alternatively, a sequential process is used to produce two or more holograms in a HO AC and a subsequent element using a single coherent source.

[0010] In addition, single film elements can be used as a functional reflection or transmission HO AC. For example, the functional layers are functionally ordered with a layer of post holographic processing hydrophobic coating; holographic recording media sensitized and functionally oriented or sensitized to a coherent light or radiation source; a thin film spacer; and a holographic recording media sensitized and functionally oriented or sensitized to a coherent radiation source different than the other holographic recording media layer.

[0011] Another particular embodiment disposes constriction layers of a passive tracking duplexed HO AC using the same coherent radiation source of two holographic recording media and adhesion of the film to, and from, the duplex. For example, the functional ordered layers include a post holographic processing hydrophobic coating; a holographic recording media oriented or sensitized to a coherent radiation source; a thin film spacer; an optical adhesive, a thin film spacer; and a holographic recording media sensitized to coherent radiation source.

[0012] These embodiments can be configured in arrays for deep or shallow water, near earth atmosphere, outer space, flat on the ground, or along all sorts of terrain and produced at configurations for maximum exposure, tracking efficiency and signal collection capacity of the dHOAC. Other similar uses include reflection of concentrated signals in a predefined spectral domain, transmission of another spectral domain of interest, and other radiative wavelengths of narrow band laser or broadband solar radiation.

[0013] Embodiments of the dHOAC have commercial and industrial applications. For example, a particular embodiment of the current disclosure provides for using a dHOAC on a residential property to simultaneously and concurrently generate electricity and heat water from the encompassed particular properties of each dHOAC or optical strip; wavelengths that are most conducive to solar electric generate are directed towards photovoltaic cells, while wavelengths that are conducive to heating water are directed towards water heating apparatuses. Other commercial and industrial uses are contemplated, such as for use on cars, campers, trailers, trucks, tall skyscrapers (ail in either vertical or horizontal configurations or both), rural, suburban, and metropolitan building structures, general commercial buildings, such as warehouses, retail stores, small business parks and the like. Industrial uses include a power generator for large institutions as in government, universities, heavy power dependent industrial complexes, such as chemical processing, oil refineries, hazard waste disposal plants, water and waste treatment plants, large manufacturing, solar farms, solar parks, photovoltaic power installations, large parking lots and structures and the like.

[0014] The dual use of the spectral radiation and incoming light in selected embodiments of the current di sclosure allows for power increase over standard photovoltaic concentrators or solar heaters. The dHOAC allows within the same square unit area for both spectral radiation to be used for photovoltaic purposes in electricity generation and reflective heat and UV for multi purposes such as heating a medium, electricity generation, cooling, and staictural protection. Other solar industry uses include, but are not limited to, solar lighting on which the passive tracking HO AC is used as a visible light collector for maximum light collection into an optical fiber that can be used to light up an enclosed area, such as warehouses, storage units, or homes. This also, for example purposes, eliminates the need to cut large holes in rooftops since significantly more light can be collected by a HO AC in a much smaller space through previously mentioned concentration methods and then transferred to any desired area of the structure with optical fibers. In situations where HO AC can enhance communication either though optical fiber or free air, for example purposes, an incoming signal from undefined or not precisely defined signal source can be collected and then focused onto a detector unit without the need of physical movement to compensate for angular changes. Detectors may include but are not limited to photomultiplier tubes, avalanche photodiodes, charge-couples device cameras, photovoltaic cells, and the like.

[0015] High level of tracking precision of herein described embodiments allows continuous tracking and collection of incoming light signal from a source with some degree of angular freedom. During recording, the passive tracking element is designed to compensate for angular changes within the range of its functionality. Solar application of HO AC allow for passive collection of solar radiation throughout daily and annual solar variations,

[0016] It is a principal object of the invention to provide a system for accepting signals from variable angles of incidence and transmitting or reflecting the signals in a predefined angle and direction,

[0017] It is another object of the invention to provide a method for making a holographic optical angular compensator that accepts signals from variable angles of incidence and transmits or reflects the signals in a predefined angle and direction.

[0018] It is a final object of this invention to provide a holographic optical element and a method for using a holographic optical element to accept signals from variable angles of incidence and transmit or reflect the signals in a predefined angle and direction.

[0019] A particular embodiment of the current disclosure is a method of producing a holographic optical angular compensator comprising the steps of producing a first generation holographic lens array on a first holographic plate; producing a subsequent generation holographic lens on a subsequent holographic plate array using either the first generation holographic lens array or a previously produced subsequent generation holographic lens array; and producing a holographic optical angular compensator (HO AC) on a HO AC plate using one of the subsequent generation holographic lens array. The step of producing a first generation holographic lens array comprises the steps of exposing an area of the first holographic plate to two coherent beams; moving the first holographic plate a distance in a first axis; exposing another area of the first holographic plate to two coherent beams; moving the first holographic plate a distance in a second axis; and exposing yet another area of the first holographic plate to two coherent beams. The first axis is perpendicular to the second axis. The first axis and second axis form a plane; where the plane is parallel to the first holographic plate. The step of producing a subsequent generation holographic lens array comprises the steps of exposing an area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent generation holographic lens array, moving the subsequent holographic plate a distance in a first axis; exposing another area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent generation holographic lens array; moving the subsequent holographic plate a distance in a second axis, and exposing yet another area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent generation holographic lens array. The first axis and second axis form a plane; where the plane is parallel to the first generation holographic lens array or a previously produced subsequent generation holographic lens array. The first generation holographic lens array has a focal length, where each exposure of an area of the subsequent holographic plate occurs at a distance that is twice the focal length from the first generation holographic lens array or a previously produced subsequent generation holographic lens array. The step of producing a holographic optical angular compensator using the subsequent generation holographic lens array comprises the steps of: exposing a first area of the HO AC plate to two coherent beams, where one of the two coherent beams is directed towards the HO AC plate by the subsequent generation holographic lens array. The step of producing a holographic optical angular compensator using the subsequent generation holographic lens array further comprises the steps of: moving the HO AC plate a distance in a first axis, where the first axis is parallel to the subsequent generation holographic lens array; moving the HOAC plate a distance in a second axis, where the second axis is perpendicular to the subsequent generation holographic lens array; and exposing an area that is substantially the same as the first area of the HOAC plate to two coherent beams, where one of the two coherent beams is directed towards the HOAC plate by the subsequent generation holographic lens array. The subsequent generation holographic lens array has a focal point, where the HO AC plate is before or after focal point of the subsequent generation holographic lens array when exposing a first area of the HO AC plate to two coherent beams.

[0020] Another embodiment of the current disclosure is a method of producing a holographic optical angular compensator comprising the steps of: producing a first generation holographic lens array on a first holographic plate by exposing an area of the first holographic plate to two coherent beams; moving the first holographic plate a distance in a first axis; and exposing another area of the first holographic to two coherent beams; producing a subsequent generation holographic lens array on a subsequent holographic plate array using the first generation holographic lens array or a previously produced subsequent holographic lens array by exposing an area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent holographic lens array; moving the subsequent holographic plate a distance in a first axis; and exposing another area of the

subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic or a previously produced subsequent holographic lens array; and producing a holographic optical angular compensator (HO AC) on a HO AC plate using the subsequent generation holographic lens array by exposing a first area of the HO AC plate to two coherent beams, where one of the two coherent beams is directed towards the HO AC plate by one of the subsequent generation holographic lens arrays; moving the HOAC plate a distance in a first axis, where the first axis is parallel to the subsequent generation holographic lens array; moving the HOAC plate a distance in a second axis, where the second axis is perpendicular to the subsequent generation

holographic lens array; and exposing an area that is substantially the same as the first area of the HOAC plate to two coherent beams, where one of the two coherent beams is directed towards the HOAC plate by one of the subsequent generation holographic lens arrays. The first generation holographic lens array has a focal length, where each exposure of an area of the subsequent holographic plate occurs at a distance that is twice the focal length from the first generation holographic lens array. The subsequent generation holographic lens array has a focal point, where the top of the HOAC plate is before or after focal point of the subsequent generation holographic lens array when exposing a first area of the HOAC plate to two coherent beams. [0021 ] Yet another embodiment of the current disclosure is an optical angular compensator comprising a holographic plate, where the holographic plate comprises a plurality of holographic pixel elements, where each holographic pixel element is created using two coherent beams, where one of the two coherent beams is from a holographic lens array, where each pixel has the same angle of acceptance, and where there is an invariant angle of diffraction with respect to the holographic plate. The plurality of holographic pixel elements comprises diverging holographic pixel elements and converging holographic pixel elements. The holographic lens array is a subsequent generation holographic lens array, where the subsequent generation holographic lens array is produced from a prior generation holographic lens array. The plurality of holographic pixel elements receives optical signals at angles deviated from a normal axis and reflect or transmit the optical signals at a predefined angle.

[0022] An additional embodiment of the current disclosure is a method of producing a holographic optical angular compensator comprising the steps of: producing a first generation holographic lens array on a first holographic plate, where the step of producing a first generation holographic lens array comprises the steps of: exposing an area of the first holographic plate to two coherent beams; moving the first holographic plate a distance in a first axis; exposing another area of the first holographic plate to two coherent beams; moving the first holographic plate a distance in a second axis; exposing yet another area of the first holographic plate to two coherent beams; and producing a holographic optical angular compensator (HO AC) on a HO AC plate using the first generation holographic lens array.

[0023] Terms and phrases used in this document, and variations thereof unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term "including" should be read as meaning "including, without limitation" or the like; the term "example" is used to provide exemplar}- instances of the item in discussion, not an exhaustive or limiting list thereof; the terms "a" or "an" should be read as meaning "at least one," "one or more" or the like, and adjectives such as "conventional," "traditional," "normal," "standard," "known" and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, where this document refers to technologies that would he apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future. Furthermore, the use of plurals can also refer to the singular, including without limitation when a term refers to one or more of a particular item; likewise, the use of a singular term can also include the plural, unless the context dictates otherwise.

[0024] The presence of broadening words and phrases such as "one or m ore," "at least," "but not limited to" or other like phrases in some instances shall not be read to mean that the narrower case i s intended or required in instances where such broadening phrases may be absent.

Additionally, the various embodiments set forth herein are described in terms of exemplary block diagrams, flow charts and other illustrations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives can be implemented without confinement to the illustrated examples. For example, block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.

[0025] As used herein, the term duplex refers to a method of at least two inputs interacting with different parts and modes of a system to create predetermined outputs in different directions, wavelength separation and modulation, of different properties and use.

[0026] As used herein, the term holographic optical element, or HOE, refers to a system of thin film diffraction optics with defined sets of configurations and properties that have opti cal properties and image characteristics that are wavelength dependent. A HOE may be a high- resolution hologram formed by interference of an incident coherent wave pattern (i.e. :

diffraction). A surface relief, or refractive index modulation formed as a consequence to such interference, produces high density fringes on a holographic recording media. The HOE can be divided into two general categories: 1 ) a reflection HOE in which the diffracted wave pattern is formed on the same side of the HOE in respect to the contraction wave; and, 2) a transmission FIOE in which the diffracted wave pattern is formed on the opposite side of the FIOE in respect to the construction wave. HOEs may also be configured with one another, such as a duplex HOE (dHOE), or in various other ways to achieve a desired outcome, as is the case of angular compensation, or duplex holographic optical angular compensator (dHOAC). [0027] As used herein, a holographic optical angular compensator (HOAC) is a holographic optical element that is designed to function within the range of angles from the normal angle of the optical axis. It is designed to compensate for angles of incoming signal such that the direction or angle of outgoing light remains unchanged within the configuration of the holographic optical element.

[0028] As used herein, holographic recording media is any material that upon irradiating with two mutually coherent light sources will record the interference patters therein, formed at sufficiently high resolution. Such material may include dichromate gelatin, materials containing silver halide, photoresist materials, and others.

[0029] As used herein, multiplexing is a method by which multiple inputs are combined into a single, functional output. In the production of HOE, multiplexing broadly defines formation of diffraction pattern (as is the case with Bragg diffraction) with relative independence to the contraction wave properties, such as the angle of incidence.

[0030] As used herein, photosensitive is having the capability to absorb an incident photon and respond or react thereafter or generally being sensitive to electromagnetic radiation. In general terms, photosensitive is often used in reference to the low energy ultraviolet, visible and near Infrared spectra of light,

[0031] As used herein, optical signals are any narrow or broadband spectrum light that is produced and/or emitted from a source, including but not limited to laser radiation, solar radiation, infrared light, ultraviolet light, or other light emitting sources.

[0032] As used herein, visible light (VIS) is defined at the spectrum of electromagnetic radiation between 400 and 800nm wavelengths that is detectable by the human eye.

[0033] As used herein, ultraviolet light (UV) is higher energy, shorter wavelength light, from 400 nm to 10 ran, as compared to the visible spectrum of light, and are the electromagnetic waves that are invisible to the human eye.

[0034] As used herein, focal point means a diffraction limited focal point which, when dealing with small dimensions, may be a considered a volume instead of a discrete point. [0035] Brewster's angle, or a polarization angle, is an angle of incidence at which light with a particular polarization is transmitted through a transparent dielectric surface with small amount of reflection. When unpolarized light is incident at this angle, the light that is reflected from the surface is therefore polarized.

[0036] There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will also form the subject matter of the claims appended hereto. The features listed herein and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.

Brief Description of the Figures

[0037] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of this invention.

[0038] Fig. 1 shows two configurations of duplex holographic optical elements according to selected embodiments of the current disclosure.

[0039] Fig. 2 is a side view of a duplex holographic optical element showing transmitted and reflected radiation according to selected embodiments of the current disclosure.

[0040] Fig. 3 is a diagram of a transmission HO AC according to selected embodiments of the current disclosure.

[0041] Fig. 4 is a diagram of a reflection HO AC according to selected embodiments of the current disclosure.

[0042] Fig. 5 is a recording schematic of a first generation lens array for a HOAC master hologram according to selected embodiments of the current disclosure. [0043] Fig. 6 is a recording schematic of a subsequent generation lens array for a HOAC master hologram according to selected embodiments of the current disclosure.

[0044] Fig. 7 is a recording schematic of a HOAC according to selected embodiments of the current disclosure,

[0045] Fig. 8 is a diagram showing the HOAC after a first recording according to selected embodiments of the current disclosure.

[0046] Fig. 9 is a recording schematic for a first recording of a HOAC according to selected embodiments of the current disclosure.

[0047] Fig. 10 is a recording schematic for a second recording of a HOAC according to selected embodiments of the current disclosure.

[0048] Fig. 11 is a diagram showing the HOAC after two recordings according to selected embodiments of the current disclosure.

Detailed Description of the Inventio

[0049] Many aspects of the invention can be better understood with the references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings.

[0050] Referring to the embodiments reflected in Fig. 1, two exemplary configurations 1041 and 1042 showing duplex holographic optical elements (dHOE), Turning to configuration 1041, the side view of the dHOE shows a structural matrix 1060 comprising of silicon or other computer chip like materials, with a hydrophobic coating 1050 surrounding the holographic media layer 100 optically oriented or sensitized to a coherent radiation source. Between the layers is an optically neutral thin film layer 1200 adhered through bonding properties inherent to the holographic media. Adjacent to the thin layer 1200 is the holographic media layer 1300 section that is also optically oriented or sensitized to a coherent radiation source different from coherent radiation source of holographic media layer 1 100, The holographic media can be of any known media such as di-photopolymers, inorganic and organic photorefractive materials, dichromatic gelatin, silver halides, photoresists, sol-gel glasses, and thermoplastic, photochromic and photodichroic materials polychromatic gels, refractive polymers, and the like.

[0051] Turning to configuration 1042, the side view of the dHOE shows a structural matrix 1060 comprising of silicon or other chip like materials, with a post processing hydrophobic coating 1050. The holographic recording media strips 1 500 and 1900 are identical media and are oriented or sensitized to optionally similar coherent radiation sources. Two thin film spacer strips 1600 and 1800 are optically insensitive and sandwiched between the media for structural integrity with an optical element adhesive 1700. Both embodiment configurations can be used alone or in tandem based on the need. Embodiment with configuration 1041 may be converted for uses where concentration is happening to both the IR and the visible spectrums of light allowing for power generation on opposing sides of the dHOE matrix chip. An embodiment with configuration 1042 may have a dual purpose of reflecting IR heat not necessarily for power production, but to reduce heat to the underlying photovoltaic cells which lose efficiency at approximately 0.5% for every one-degree temperature rise. This configuration may also select ultra-violet (UV) light, which includes higher energy waves and contains strong degradation properties for the crystalline structures of the photovoltaic cells. The optical element media detailed allows light to be concentrated on the photovoltaic ceils to exponentially increase the power per square meter. The transparent hydrophobic coating 1050 allows among other things to protect the dHOE from incidental contacts with other items, environmental protection from the wind, rain and dust, and creates a slick barrier for cleaning.

[0052] Fig. 2 shows a side view of a dHOE from configuration 1041, with three graphs of the radiation source signature utilizing a simple full spectrum detector oriented to detect 1) the incoming radiation source signatures of UV, visible, and IR wavelengths; 2) the radiation source signatures reflecting off the top side of the dHOE (the detector aperture oriented on the top side); and 3) the radiation source signatures transmitting through the dHOE (the detector aperture oriented on the bottom side). As expected, graph 1 150 shows the full spectrum that is available for utilization by the dHOE. Graph 152 shows the spectrum after reflection or transmission of wavelengths not in the visible spectrum, which are IR. (i.e.: a heat signature) and UV with a pass through transmission or refection (inversion of the earlier) as to the visible light range wavelength of approximately 400 nm to 800 nm. Looking at Graph 1153, the visible light spectrum is detected with all other wavelengths on the graph being absorbed, blocked or diverted from the detector by the spectral selective layers of the dHOE. Note: Ail component in Fig. 2 hologram are discussed in Fig 1.

[0053] Referring to the embodiments reflected in Fig, 3, an example of the confi guration of a transmission HOAC. Here the HOAC 1000, with the passive tracking domain 1010 with angles of freedom of 1020a and 1020b. The HOAC 1000 will accept signals from throughout the domain 1010 and compensate for variations in angle on incidence by diffracting light at the predefined angle 1030. The signal out of the HOAC has minimal angular variations that comply with the optical axis of the subsequent downstream detection or collection machinery 1040, The collection machinery 1040 may be composed of further optical elements (diffracting and/or refractive) and/or fiber and/or direct photodetectors and/or photovoltaic cells and/or thermal conduits.

[0054] Referring to the embodiments reflected in Fig. 4, an example of the configuration of a reflection HOAC. Here the HOAC 1002, with the passive tracking domain 1010 with angles of freedom of 1020a and 1020b, The HOAC 1002 will accept signal from throughout the domain 1010 and compensate for variations in angle on incidence by diffracting light at the predefined angle 1032. The signal out of the HOAC has minimal angular variations that comply with the optical axis of the subsequent downstream detection or collection machinery 1040. The collection machinery 1040 may be composed of further optical elements (diffracting and/or refractive) and/or fiber and/or direct photodetectors and/or photovoltaic ceils and/or thermal conduits.

[0055] To produce a specific HOAC with angles of response of interest, initially a holographic lens array, also referred to as a generation hologram, is made. General recording schematics of a first generation lens array for a HOAC master hologram is presented in Fig. 5. The hologram is written on a holographic plate 100 sensitized for the wavelength of the two mutually coherent beams 102 and 105 used in recording resulting in an exposed area 101. Furthermore, the direction of incidence of beam 102 onto the plate 100 beam determines if the hologram will function as a transmissive or reflective hologram. When the directions of beams of 102 and 105 are incident upon the same side of the holographic plate 100, for example, beam 102 in direction 103, the resulting plate is transmissive. When the direction of beams 102 and 105 are incident upon different sides of the holographic plate 100, for example, beam 102 in direction 104, the resulting plate is reflective. The holographic plate 100 is exposed multiple time, and between each exposure, the holographic plate 100 is moved a distance. This distance is in an x or y axis, each of which form a plane which is perpendicular to incident beam 105. This is repeated multiple times, where the holographic plate is exposed and then moved a distance d to form an array of exposures on the holographic plate. The distance moved corresponds to the pixel size of the final HOAC in both the x and y axis, thereby forming a two-dimensional lens array of a size corresponding to the total distances moved in both the x and y axis. For example, the holographic plate may be exposed four times in the x direction in each of four unit movements in the y direction to create a four by four unit matrix of sixteen pixel exposures on the holographic plate. Particular embodiments of the current disclosure provide for a distance of each movement in the x or y axis to be less than that of the exposed area 101.

[0056] An alternative embodiment of the current disclosure has a first generation holographic lens array that is only exposed once. This single-exposure first generation holographic lens array may be used to create subsequent generation holographic lens arrays, or in rare circumstances, may be used to create the final HOAC.

[0057] The angle 107 determines the response angle of the final HOAC, whereas angle 108 is chosen to be the Brewster's angle for maximum efficiency. The plate is repeatedly exposed from one time to several hundred times. The focal length of the resulting holographic lens array is the distance between the plate 100 and point of divergence 109 of beam 105 of the optical component, for example, including but not limited to a concave or convex lens, spatial filter or convex of concave mirror.

[0058] Fig. 6 generally shows the production of a subsequent generation hologram. The hologram is written by using the first or previous generation lens array hologram discussed above in reference to Fig. 5. The first generation hologram 100 is played back with beam 102, at direction 103 or direction 104, depending if it is a transmissive or refl ective hologram, respectively. The holographic plate 200 for making the subsequent generation hologram is placed at a distance 205 from the first generation hologram 100, Particular embodiments provide that the distance 205 is two times the focal length of the first generation hologram. The second generation holographic plate 200 is written just like first generation holographic plate 100, in which the plate 200 is moved parallel to the plate 100 between exposures in both the x and y axis. Particular embodiments provide that the distance displaced between each exposure is equal to the total size of the first or prior generation hologram, thereby forming exponentially larger two dimensional arrays of lenses. For example, if the first generation lens array is four units by four units in size, the second generation hologram plate would be moved in four unit increments in the x or y direction.

[0059] As will be appreciated by those skilled in the art, the step of making subsequent generation holograms can be repeated to create exponentially larger sized lens arrays. For example, the second generation holographic plate may be used to produce a third generation holographic plate, which in turn can be used to create a fourth generation holographic plate. While theoretically possible to use a first generation holographic plate only, exposed individually multiple times, this has several drawbacks. The drawbacks of such a process include slower production times as well as difficulty in exposing the holographic plate fast enough, since once a photosensitive material is exposed to light, it begins to harden and thus after a few dozen exposures, further recording becomes difficult if not impossible. One skilled in the art will appreciate that instead of moving the plate in an x or y direction, and equivalent procedure is to move the beams a corresponding (yet opposite) distance while leaving the plate fixed.

[0060] Once the second generation hologram is written, the HO AC is produced from the second generation hologram as generally shown in Fig, 7. The final generation hologram 301 is played back with beam 302 at directions 304 for reflection and direction 303 for transmission holograms, as determined during recording of the second generation hologram. The HO AC plate 308 is placed in the vicinity of the foci of the generation hologram such that the total aperture of the plate is filled with light from the second generation hologram lens array. Note that this is such that the foci are before the plate or holographic recording film or after the plate or holographic recording film, or before and after the plate or holographic recording film in the case of a twice recorded plate, discussed in more detail below. Another beam 305 which is coherent to that of 302 is used as a reference beam to record the HO AC. Direction of 305 determines the reflection or transmission of the final HOAC such that direction 306 forms a transmission HOAC and direction 307 forms a reflection HOAC.

[0061] Fig. 8 is a diagram showing the HOAC after a first recording according to selected embodiments of the current disclosure. The final generation hologram (now shown in this figure) when played back with beam produces recorded beams 510. In this particular embodiment, the top of the plate 308 is placed before or after the focal point of the recorded beams 510. The recorded beams 510 and coherent beam 205 record pixel elements 550. In this figure, the pixel elements are formed as diverging pixel elements.

[0062] Particular embodiments of the current disclosure provide for the method being completed at this point, and the holographic optical angular compensator being ready for use, as shown in Figs. 3 and 4 above. However, as will be appreciated by those skilled in the art, there are significant areas of the holographic plate that remain unrecorded, and thus may not diffract optical signals as efficiently as the HOACs discussed below.

[0063] Fig. 9 is a recording schematic for a first recording of a HOAC according to selected embodiments of the current disclosure. Similar to that discussed above, the final generation holographic plate 301 is played back with a beam 302 which produces recorded beams 510. The embodiment exemplified by this figure shows the bottom of plate 308 placed before the focal point of the recorded beams 510. The recorded beams 510 interact with coherent beam 205 in the media of plate 308 to record pixel elements 540,

[0064] Fig. 10 is a recording schematic for a second recording of a HOAC according to selected embodiments of the current disclosure. The process continues by displacing plate 308 some distance parallel to plates 308 and 301 as well as some distance perpendicular to plates 308 and 301 such that the focal point of the negation hologram is now on the opposite side of the film compared to the first recording orientation of the focus of generation hologram in the first recording. Particular embodiments provide for di splacing the plates away from each other, that is in a direction that is perpendicular to plates 308 and 301, such that the top of plate 308 is at the focal point of the recorded beams 510. The final generation holographic plate 301 is then once again played back with a beam 302 which produces recorded beams 510. The recorded beams 510 interact with coherent beam 205 in the media of plate 302 to record pixel elements 550. The distance the plate 308 is displaced parallel to plates 301 and 308 is determined so that pixel elements 540 are between pixel elements 550,

[0065] Those skilled in the art will appreciate that pixels 550 may be recorded before pixels 540, the order in which the pixels are recorded may be reversed. Furthermore, placing the focus of recorded beams 510 exactly before or after (that is, proximate to the top or bottom) of recording media 308 may be difficult or impractical in certain situations, and thus some displacement of the top or bottom of the recording media from the focus of recorded beams 510 is contemplated. It is important that the focal point of the prior holographic lens array never be within the plate or recording media of the HO AC.

[0066] Fig. 11 is a diagram showing the HO AC after two recordings according to selected embodiments of the current disclosure. The plate 308 is composed of individual pixels 540 and 550, which are recorded as discussed above. The output direction of the resulting HOAC is determined during the recording process and may be either reflective or transmissive. The spacing between holographic pixel elements 550 and 540 is chosen to minimize crosstalk between individual pixel elements while minimizing the overall space required to hold the pixels. The thickness 480 of the recording film or plate 308 may be modulated during the curing process in order to tune the bandwidth response of the holographic optical angular compensator.

[0067] When recording the HOAC, care should be taken to avoid overlapping pixels. When pixels are recorded too close together, or even on top of one another, cross-talk may occur.

While the resulting HOAC may still transmit or reflect light as expected, it may do so at a lower effi ciency. Furthermore, if the final HOAC is recorded on only one side, that is, it is recorded with the focal point of the prior generational holographic lens either before or after the plate of the final HOAC, the resulting HOAC is the same; optical signals will be passively tracked and redirected at the same angles. However, the efficiency of only recording on one side is less, since there are fewer pixels (recorded holographic area) per volume of plate. Thus, it is advantageous to pack the pixels as close together as possible while avoiding cross-talk between the pixels. [0068] Another embodiment of the current disclosure is a method of making an HOAC using only a first generation holographic lens array. The first generation lens array is produced using the methods described above, wherein multiple exposures are made. The first generation lens array is then used to make the HOAC, wherein multiple expires of the HOAC plate are accomplished using the first generation lens array.

[0069] The HOAC simplifies the tracking necessities because of wide angle of acceptance of light (i.e. from an unknown angle) and output light at a predefined angle with respect to the plane of the hologram . This means that regardless of the angle at which the light or light signal reaches the hologram, the output angle of the diffracted light from the HOAC remains unchanged. This, in turn, means that this light can be collected and processed downstream without the need to move anything with respect to the HOAC. In addition, the duplex nature of the dHOAC allows for spectral separation between reflection and transmission component of the duplex holographic element or different angle of acceptance of light between transmission and reflection components of the duplex hologram.

[0070] The following is an example of a general configuration, description of tools chosen, and method that may be used to make the generation holographic lens arrays as well as the HOAC element on a 6 inch by 6 inch holographic recording plate in the transmission mode. The initial or first generation holographic lens array is made by exposing a holographic recording film, such as 8 micron or micrometer (urn) thick dichromated gelatin film on a glass substrate (plate) with two mutually coherent beams using a 532nm laser. Beam one is a coliimated beam that is directed onto the film at 56 degrees from the normal. Beam two approaches the plate at normal through a spatial filter (objective lens and a pinhole at the focal point of the lens) without any additional optics, therefore forming a diverging beam. The distance between the spatial filter and the plate is 4 inches from the plane of the holographic plate. This distance is important for the final step when making a HOAC because this distance determines the focal length of the generation holographic lens array. Once the setup is assembled, the plate is exposed four times in the x direction for each of four times in the y direction, each exposure a distance of 1 mm from the previous exposure, resulting in a lens array on that plate that is 4 mm by 4 mm after 16 exposures. Once the plate is developed, it forms the generation 1 hologram. The focal length of the generation 1 holographic lens array is 4 inches. [0071 ] To make generation 2, the generation 1 hologram is placed back in its original position while flipping it 180 degrees with respect to the incoming beam. A new plate for a holographic lens array is placed at a distance of two times the focal distance of the generation 1 holographic lens array, or a distance of 8 inches. Beam two is reconfigured to form a second collimated beam incident upon the new plate at 56 degrees. The beams formed by the generation 1 lens array from its transmission of beam 1 therefore becomes the second lens for making the subsequent hologram. Twi ce the focal distance ensures that the focal length of each generation lens array does not change and remains the same. Once the setup is assembled the plate of the generation 2 lens array is exposed 4 times in the x direction for each of four times in the y direction, each exposure a distance of 4 mm from the previous exposure, resulting in a lens array on that plate that is 16 mm by 16 mm after 16 exposures. Once the plate is developed, it forms the generation 2 hologram. The focal length of the generation 2 holographic lens array is 4 inches.

[0072] To form a HOAC using the second generation holographic lens array, the generation 2 hologram is placed in the beam path of the original beam 1 for playback (meaning flipped by 180 degrees with respect to the incoming beam). Beam two is now moved to cover a HOAC plate that is placed near the focal point of the generation 2 holographic lens array, or around 4 inches. The final plate for making the HOAC is placed such that the focal points of each lens in the holographic lens array (generation 2 hologram) is before or after the film. The HOAC plate is then exposed to beam 1 reconstructed generation 2 hologram's lens and beam 2. The HOAC plate is then shifted parallel to the generation 2 hologram a distance of 0.5 mm. The HOAC is also shifted perpendicular to the generation 2 hologram a distance of more than 8 um, such that if the focal point was before the film it is now after the film, and if the focal point was after the film, it is now before the film. In each case the focal point is not in the film. The HOAC plate is then exposed to beam 1 (via generation 2 hologram) and beam 2. These two exposures result in 16 mm by 16 mm HOAC that has 256 diverging pixels and 256 converging pixels for a total of 512 pixel elements.

[0073] It is important to note that the HOAC can be made using any generation hologram, including the generation 1 holographic lens array. Furthermore, the final HOAC does not have to be a single area exposure; rather, the plate can be exposed and moved to a new area repeatedly to form a larger HO AC.

[0074] Indeed, it will be apparent to one of skill in the art how alternative functional

configurations can be implemented to implement the desired features of the present invention. Additionally, with regard to flow diagrams, operational descriptions and method claims, the order in which the steps are presented herein shall not mandate that various embodiments be implemented to perform the recited functionality in the same order unless the context dictates otherwise.

[0075] Although the invention is described above in terms of various exemplar}' embodiments and implementations, it should be understood that the various features, geometries, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the other embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments.

Claims

CLAIMS That which is claimed:

1. A method of producing a holographic optical angular compensator comprising the steps of:

producing a first generation holographic lens array on a first holographic plate;

producing a subsequent generation holographic lens on a subsequent holographic plate array using either the first generation holographic lens array or a previously produced subsequent generation holographic lens array; and

producing a holographic optical angular compensator (HO AC) on a HO AC plate using one of the subsequent generation holographic lens array,

2. The method of claim 1, wherein the step of producing a first generation holographic lens array comprises the steps of:

exposing an area of the first holographic plate to two coherent beams;

moving the first holographic plate a distance in a first axis;

exposing another area of the first holographic plate to two coherent beams;

moving the first holographic plate a distance in a second axis; and

exposing yet another area of the first holographic plate to two coherent beams.

3. The method of claim 2, where the first axis is perpendicular to the second axis.

4. The method of claim 2, where the first axis and second axis form a plane; where the pl ane is parallel to the first holographic plate.

5. The method of claim 1, wherein the step of producing a subsequent generation holographic lens array comprises the steps of

exposing an area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent generation holographic- lens array;

moving the subsequent holographic plate a distance in a first axis;

exposing another area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent generation holographic lens array;

moving the subsequent holographic plate a distance in a second axis; and

exposing yet another area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent generation holographic lens array.

6. The method of claim 5, where the first axis is perpendicular to the second axis.

7. The method of claim 5, where the first axis and second axis form a plane; where the plane is parallel to the first generation holographic lens array or a previously produced subsequent generation holographic lens array.

8. The method of claim 5, wherein the first generation holographic lens array has a focal length, where each exposure of an area of the subsequent holographic plate occurs at a distance that is twice the focal length from the first generation holographic lens array or a previously produced subsequent generation holographic lens array.

9. The method of claim 1, wherein the step of producing a holographic optical angular compensator using the subsequent generation holographic lens array comprises the steps of: exposing a first area of the HO AC plate to two coherent beams, where one of the two coherent beams is directed towards the HOAC plate by the subsequent generation holographic lens array.

10. The method of claim 9, wherein the step of producing a holographic optical angular compensator using the subsequent generation holographic lens array further comprises the steps of:

moving the HOAC plate a distance in a first axis, where the first axis is parallel to the subsequent generation holographic lens array;

moving the HOAC plate a distance in a second axis, where the second axis is

perpendicular to the subsequent generation holographic lens array; and

exposing an area that is substantially the same as the first area of the HOAC plate to two coherent beams, where one of the two coherent beams is directed towards the HOAC plate by the subsequent generation holographic lens array.

11. The method of cl aim 9, wherein the subsequent generation holographic lens array has a focal point, where the HO AC plate is after focal point of the subsequent generation holographic lens array when exposing a first area of the HOAC plate to two coherent beams,

2. The method of claim 9, wherein the subsequent generation holographic lens array has a focal point, where the HOAC plate is before focal point of the subsequent generation

holographic lens array when exposing a first area of the HOAC plate to two coherent beams.

13. A method of producing a holographic optical angular compensator comprising the steps of:

producing a first generation holographic lens array on a first holographic plate by

exposing an area of the first holographic plate to two coherent beams;

moving the first holographic plate a distance in a first axis; and

exposing another area of the first holographic to two coherent beams;

producing a subsequent generation holographic lens array on a subsequent holographic plate array using the first generation holographic lens array or a previously produced subsequent holographic lens array by

exposing an area of the subsequent holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic lens array or a previously produced subsequent holographic lens array;

moving the subsequent holographic plate a distance in a first axis; and

exposing another area of the subsequen holographic plate to two coherent beams, where one of the two coherent beams is directed towards the subsequent holographic plate by the first generation holographic or a previously produced subsequent holographic lens array; and

producing a holographic optical angular compensator (HOAC) on a HOAC plate using the subsequent generation holographic lens array by

exposing a first area of the HOAC plate to two coherent beams, where one of the two coherent beams is directed towards the HOAC plate by one of the subsequent generation holographic lens arrays;

moving the HOAC plate a distance in a first axis, where the first axis is parallel to the subsequent generation holographic lens array; moving the HO AC plate a distance in a second axis, where the second axis is perpendicular to the subsequent generation holographic lens array; and exposing an area that is substantially the same as the first area of the HO AC plate to two coherent beams, where one of the two coherent beams is directed towards the HOAC plate by one of the subsequent generati on holographi c lens arrays.

14. The method of claim 13, wherein the first generation holographic lens array has a focal length, where each exposure of an area of the subsequent holographic plate occurs at a distance that is twice the focal length from the first generation holographic lens array.

15. The method of claim 13, wherein the subsequent generation holographic lens array has a focal point, where the HOAC plate is after focal point of the subsequent generation holographic lens array when exposing a first area of the HOAC plate to two coherent beams,

16. The method of claim 13, wherein the subsequent generation holographic lens array has a focal point, where the HOAC plate is before focal point of one of the subsequent generation holographic lens array when exposing a first area of the HOAC plate to two coherent beams.

17. An optical angular compensator comprising

a holographic plate, where the holographic plate comprises a plurality of holographic pixel elements, where each holographic pixel element is created using two coherent beams, where one of the two coherent beams is from a holographic lens array, where each pixel has the same angle of acceptance, and where there is an invariant angle of diffraction with respect to the holographic plate.

8. The optical angular compensator of claim 17, wherein the plurality of holographic pixel elements compri ses diverging holographic pixel elements and converging holographic pixel elements.

19. The optical angular compensator of claim 17, wherein the holographic lens array is a subsequent generation holographic lens array, where the subsequent generation holographic lens array is produced from a prior generation holographic lens array.

20. The optical angular compensator of claim 17, wherein the plurality of holographic pixel elements receives optical signals at angles deviated from a normal axis and reflect or transmit the optical signals at a predefined angle. 21 , A method of producing a holographic optical angular compensator comprising the steps of:

producing a first generation holographic lens array on a first holographic plate, where the step of producing a first generation holographic lens array comprises the steps of:

exposing an area of the first holographic plate to two coherent beams,

moving the first holographic plate a distance in a first axis;

exposing another area of the first holographic plate to two coherent beams;

moving the first holographic plate a distance in a second axis;

exposing yet another area of the first holographic plate to two coherent beams; and producing a holographic optical angular compensator (HO AC) on a HO AC plate using the first generation holographic lens array.