Abstract: An optical irradiation device for the polarization of alkali metal atoms for the hyperpolarization of noble gases by spin exchange includes at least one semiconductor laser device which can generate laser light which, with regard to its wavelength, is suitable for the polarization of the alkali metal atoms. A polarizer effects circular polarization of the laser light generated by the semiconductor laser device. A device for introducing the laser light into a working region in which the alkali metal atoms to be polarized can be present, and a device for defining a wavelength of the laser light, which can couple part of the laser light back into the semiconductor laser device in order thereby to define the wavelength of the laser light at a predetermined wavelength or a predetermined wavelength range.

Abstract: A variety of lenses, lens assemblies, imaging devices, applications for such lenses, assemblies and devices, and related methods of operation and manufacturing are disclosed. At least some embodiments of the invention relate to a lens that includes first and second inward-facing surfaces that are each at least partly reflective. The lens further includes a first aperture that is positioned around at least a portion of an outer periphery of one of the first and second inward-facing surfaces, and a second aperture existing proximate a central region of the lens. The light proceeding within the lens between the first and second inward-facing surfaces is reflected at least twice on at least one of the first and second inward-facing surfaces as it travels between the first aperture and the second aperture.

Abstract: End reflectors, flat panel lens that may utilize the end reflector, and methods are provided. The end reflector for a flat panel lens may include a first grating having a first set of parallel planes. The first set of parallel planes may be of layers of alternating refractive indexes disposed at a first angle with a central plane of the flat panel lens. The end reflector may also include a second grating having a second set of parallel planes. The second set of parallel planes may be of layers of alternating refractive indexes of alternating refractive indexes disposed at a second angle with the central plane. The second angle may be equivalent to the first angle reflected about the central plane.

Abstract: A method of adjusting the pupil delay compensation of a convergent or divergent beam that includes placing a device composed of an afocal system comprising one or more passive optical components disposed on the propagation axis of the beam, at least one of the components being a focusing diffractive component, and moving the device along the propagation axis of the beam until the required pupil delay compensation is obtained, where the compensation is the algebraic sum of pupil delays of each passive optical component of the afocal system and lying in a range of values the limits of which are functions of the particular combination of the optical components chosen to form the afocal system of the compensation device.

Abstract: An optical relay comprises a light-transmissive substrate having a plurality of diffractive optical elements, where at least one diffractive optical element is characterized by nonuniform diffraction efficiency. The substrate and diffractive optical elements are designed and constructed to relay at least a portion of a light beam emanating from an object to at least one predetermined eye-box in a manner such that for each point of the object, there is a set of parallel outgoing light rays originating from the point and arriving to the eye-box. The color difference between any two parallel light rays of the set is less than 50 ?E* units.

Abstract: The present invention provides a wavelength-selective diffraction element, configured such that light having a plurality of wavelengths are incident thereon as incident light, which is provided with: a transparent substrate; a concavo-convex part, formed on the transparent substrate such that concave portions and convex portions are cyclically extended in one direction, and comprised of a first material which is optically isotropic; and a filling part, filling at least the concave portions and comprised of a second material which is optically isotropic. The first material and the second material have no absorbance with respect to the wavelengths of the incident light. The first material and the second material have an identical refractive index with respect to light having a first wavelength which is at least one of the wavelengths of the incident light.

Abstract: A bistable electroactive polymer transducer is provided for electrically actuated deformation of rigid electroactive polymer members. The polymers have glass transition temperatures (Tg) above ambient conditions and turn into rubbery elastomers above Tg and have high dielectric breakdown strength in the rubbery state. They can be electrically deformed to various rigid shapes with maximum strain greater than 100% and as high as 400%. The actuation is made bistable by cooling below Tg to preserve the deformation. The dielectric actuation mechanism includes a pair of compliant electrodes in contact with a dielectric elastomer which deforms when a voltage bias is applied between the pair of electrodes. In some of the transducers of the present invention, the dielectric elastomer is also a shape memory polymer. The deformations of such bistable electroactive polymers can be repeated rapidly for numerous cycles.

Abstract: A method for producing a grating image, which has at least one grating field recognizable with the naked eye, in which are disposed grating elements, which are produced by a writing apparatus. In a first procedure step at least one grating element is determined, which completely lies within one working field. Then a sequence of working fields is defined, in which the grating elements are to be produced by the writing apparatus. Finally, the working fields are moved to by a relative movement of a carrier, on which is located a substrate to be inscribed, and the writing apparatus, and the grating elements are written into the substrate with the writing apparatus within the respective working fields.

Abstract: A rewriteable diffraction grating contains first nanoparticles and second nanoparticles. Each first nanoparticle is configured and arranged to generate one or more charge carriers in response to a write beam. Each second nanoparticle is configured and arranged to substantially alter its response to light from a read beam upon receiving one or more charge carriers from the first nanoparticles. The second nanoparticles are disposed in proximity to the first nanoparticles to permit charge carriers generated by the first nanoparticles to interact with the second nanoparticles.

Abstract: An optical signal control system is constructed from a portion of a material and allows for controlled amount of negative dispersion to be generated across a broadband input signal. The block may be made of a single portion of the material and have surfaces with reflective, transmissive, and/or diffractive optical characteristics. By adjusting the physical dimensions of the block substrate and the line pitch of a diffraction grating etched into a surface of the block, the magnitude of the dispersion can be varied. Laser systems that utilize the optical signal control system may have reduced size and weight as compared to existing compressors and be more robust against misalignment.

Abstract: Provided is a tunable diffraction grating apparatus including: a diffraction grating portion having a diffraction grating with an linearly variable grating interval, the diffraction grating being formed of an elastic member; a drive portion connected to the diffraction grating portion and applying a force to the diffraction grating portion to vary the grating interval; and a controller for controlling the drive portion to adjust the grating interval depending on a specific wavelength input from the exterior. Therefore, the tunable diffraction grating apparatus can vary a grating interval of a diffraction grating using an elastic material so that a signal of a frequency bandwidth of THz can also be used. In addition, it is possible to simplify structure of the apparatus to reduce the manufacturing cost thereof.

Abstract: The invention relates to an optical system that particularly allows an improved detection of signal light propagating from a light source (1) through a flat glass substrate (11). SC-modes of this signal light that would normally be totally internally reflected at the backside (10) of the substrate (11) are coupled out by a first diffractive optical element DOE (21). To map all signal light leaving the substrate (11) onto a single target location (51), a focusing lens (31) and a second DOE (41) are disposed in the optical path behind the substrate (11). The DOEs (21, 41) may for example be a ID sinusoidal grating or a 2D blaze grating. The optical system may particularly be applied in an investigation apparatus for detecting multiple spots of a fluorescent sample material.

Abstract: An optical pickup which includes first to third light sources each emitting a light beam each having a first to third wavelength; an objective lens condensing each of the light beams emitted from the light sources on a signal recording face of an optical disc; a collimator lens provided between the light sources and the objective lens to convert a divergent angle of each of the light beams emitted from the light sources so as to obtain a parallel light beam; and a diffractive optical element provided between the collimator lens and the objective lens. The diffractive optical element includes first and second diffractive parts which respectively diffract the light beam having the second wavelength and the third wavelength. The second diffractive part has a diffraction structure formed by a plurality of concentric ring zones, having first to fourth optical faces, each having a different height in an optical axis direction.

Abstract: A scanning head for an optical position-measuring system includes a receiver grating, formed of photosensitive areas, for the scanning of locally intensity-modulated light of differing wavelengths. The receiver grating is formed from a semiconductor layer stack of a doped p-layer, an intrinsic i-layer and a doped n-layer. The individual photosensitive areas have a first doped layer and at least a part of the intrinsic layer in common and are electrically separated from one another by interruptions in the second doped layer.

Abstract: A composite light dividing device is provided. The composite light dividing device receives a light beam mixed by lights of at least two wavebands. The composite light dividing device includes a refracting/diffracting unit, and a refracting unit. The refracting/diffracting unit is adapted for receiving the light beam and condensing the light beam into a condensed light beam, and dividing the condensed light beam at a deflection direction to obtain the lights of the wavebands. The refracting unit is adapted for deflecting the divided lights of the wavebands for outputting them from a specific direction. The composite light dividing device for example can be used in an image apparatus, and the divided lights of the wavebands can serve as primary color lights of the pixel colors.

Abstract: The present invention relates to a grating image having one or more grating fields, each of which includes an electromagnetic radiation-influencing grating pattern comprising a plurality of grating lines, the grating lines being characterized by the parameters orientation, curvature, spacing and profile. According to the present invention, in the grating image, a grating field (30) that is separately perceptible with the naked eye includes an electromagnetic radiation-influencing grating pattern having grating lines (32) for which at least one of the characteristic parameters orientation, curvature, spacing and profile varies (34) across the surface of the grating field.

Abstract: There is provided a light source device which can miniaturize a two-dimensional image display device as small as possible. The light source device is provided with three coherent light sources (11a), (11b), and (11c) corresponding to red, blue, and green; prisms (12a) and (12c) for reflecting lights emitted from the coherent light sources (11a) and (11c); and a diffraction part (20) comprising a single volume hologram on which plural gratings are multiply-formed, which gratings diffract the light emitted from the coherent light source (11b), and the lights that are emitted from the coherent light sources (11a) and (11c) and reflected by the prisms (12a) and (12b) so that these lights propagate in the same optical path.

Abstract: An apparatus is disclosed which may comprise a grating receiving light, a first prism moveable to coarsely select an angle of incidence of the light on the grating, and a second prism moveable to finely select an angle of incidence of the light on the grating. In one application, the apparatus may be used as a line narrowing module for a laser light source.

Abstract: A monolithic Offner spectrometer is described herein as are various components like a diffraction grating and a slit all of which are manufactured by using a state-of-the-art diamond machining process. In one embodiment, a monolithic Offner spectrometer is directly manufactured by using a diamond machining process. In another embodiment, a monolithic Offner spectrometer is manufactured by using molds which are made by a diamond machining process. In yet another embodiment, a diffraction grating is directly manufactured by using a diamond machining process. In still yet another embodiment, a diffraction grating is manufactured by using a mold which is made by a diamond machining process. In yet another embodiment, a slit is directly manufactured by using a diamond machining process.

Abstract: The present invention provides a solid-state imaging apparatus and the like which is able to support an optical system whose incident angle is wide. Each pixel is 2.25 ?m square in size, and includes a distributed index lens (1), a color filter (for example, for green) (2), an Al interconnections (3), a signal transmitting unit (4), a planarized layer (5), a light-receiving device (Si photodiodes) (6), and an Si substrate (7). The two-stage concentric circle structure of the distributed index lens is formed by SiO2 (n=2) with the film thickness 1.2 ?m (“grey color”), the film thickness 0.8 ?m (“dots pattern”) and the film thickness of 0 ?m (“without pattern: white color”), and the medium surrounding the distributed index lens (1)is air (n=1).

Abstract: A chirp optical waveguide includes a chirp grating formed in a ferroelectric substrate, and a waveguide part orthogonal to the chirp grating. The chirp grating has a plurality of grating segments and has a normalized grating period ?x/?0 that increases exponentially in each grating segment and decreases stepwise from each grating segment to a following one of the grating segments, where ?0 is an initial grating period at the wave propagation distance of zero, and ?x is a grating period at the wave propagation distance of x. The chirp grating provides high wave conversion efficiency for short pulse widths and effectively compensates for a reduction in conversion efficiency due to chromatic dispersion.

Abstract: The specification and drawings present a new apparatus and method for near-to-eye (e.g., retinal) displaying with exit-pupil expansion using a scanning component (e.g., a scanning mirror) and an exit-pupil expander (e.g., diffractive exit-pupil expander) for providing a retinal scanning display with a large exit pupil.

Abstract: Provided are an easy-to-handle thin diffraction type light-condensing film exhibiting high light transmissivity and condensation ability, and a planar light source device using the film. A hologram optical element using diffraction/interference phenomena based on wave properties of light is used instead of a conventional prism sheet using refraction. As a result, the diffraction type light-condensing film and the planar light source device have high light transmissivity and are thin. In the diffraction type light-condensing film, dependence of bending angle on wave length is low and light entering from an oblique direction is bent in the vertical direction and emitted with spectral separation of white light suppressed. High light-condensation impossible in a conventional optical element is realized by suppressing angular variation in emission light for angular variation in incident light.

Abstract: An optical film 10 has a transparent base film 11 made of polyethylene terephthalate (PET), a prism made of photo-curing resin such as acryl modified epoxy on an incident surface 12 that is one face of the base film 11, and a hologram similarly made of photo-curing resin on an exit surface 13 opposing the incident surface 12. The prism has grooves or ridges each having a substantially triangular cross section to totally reflect incident light so as to bend the light into a direction perpendicular to the exit surface 13. The hologram anisotropically diffuses light exiting from the exit surface 13, to improve brightness.

Abstract: An optical structure includes a light transmissive substrate having a surface relief pattern applied thereon, such as a hologram. One or more layers can be patterned corresponding to materials playing the role of absorbers or reflectors on a Fabry-Perot type of optical structure. These materials are applied over portions of the surface relief pattern so as to form alphanumeric characters, bars codes, or pictorial or graphical designs. Additional layers may be applied to the patterned layer of the reflective or absorber materials and exposed portions of the surface relief pattern in order to provide desirable optical effects to the exposed portions of the surface relief pattern. In some embodiments, the optically active coating is a color shifting thin film, or contains color shifting flakes based on Fabry Perot designs.

Abstract: A solid-state imaging apparatus includes a plurality of unit pixels with associated microlenses arranged in a two-dimensional array. Each microlens includes a distributed index lens with a modulated effective refractive index distribution obtained by including a combination of a plurality of patterns having a concentric structure, the plurality of patterns being divided into line widths equal to or shorter than a wavelength of an incident light. At least one of the plurality of patterns includes a lower light-transmitting film having the concentric structure and a first line width and a first film thickness, and an upper light-transmitting film having the concentric structure configured on the lower light-transmitting film having a second line width and a second film thickness. The distributed index lens has a structure in which a refractive index material is dense at a center and becomes sparse gradually toward an outer side in the concentric structure.

Abstract: A multi-layered diffraction optical element, comprises a transparent substrate, a first layer having a diffraction grating shape at least on one face and comprised of a relatively high refractive index and low dispersion material, and a second layer having a diffraction grating shape at least on one face and comprised of a relatively low refractive index and high dispersion material, wherein the first and second layers are laminated on the transparent substrate so that the respective diffraction grating shapes are mutually opposed to each other with no space therebetween, and, the first layer is comprised of a first organic resin including a first inorganic fine particle, and the second layer is comprised of a second organic resin including a second inorganic fine particle different from the first inorganic fine particle.

Abstract: The invention relates to a device for generating a periodical array of light spots from an input light beam, said device comprising—a periodical array of apertures (202) forming a plurality of interlaced sub-arrays of apertures,—phase shifter elements (PS;) placed in front of said apertures for imposing a phase shift to said input light beam so that each light spot is constructed as the superposition of a plurality of light spots generated by said plurality of interlaced sub-arrays of apertures. Use: Light spot generation.

Abstract: An optical characterisation system is described for characterising optical material. The system typically comprises a diffractive element (104), a detector (106) and an optical element (102). The optical element (102) thereby typically is adapted for receiving an illumination beam, which may be an illumination response of the material. The optical element (102) typically has a refractive surface for refractively collimating the illumination beam on the diffractive element (104) and a reflective surface for reflecting the diffracted illumination beam on the detector (106). The optical element (102) furthermore is adapted for cooperating with the diffractive element (104) and the detector (106) being positioned at a same side of the optical element (102) opposite to the receiving side for receiving the illumination beam.

Abstract: A diffraction grating including a substrate, and a grating member formed on the substrate, the grating member having a stepped structure including steps, the number of which corresponds to an odd number greater than or equal to three to provide an odd phase structure. The heights of the steps of the grating member are determined such that the light beams diffracted by their corresponding steps substantially have a phase difference of ? with reference to a diffracted light beam of a reference wavelength.

Abstract: A dynamic optical grating device and associated method for modulating light is provided that is capable of controlling the spectral properties and propagation of light without moving mechanical components by the use of a dynamic electric and/or magnetic field. By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmittivity, and the reflectivity of the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by the device.

Abstract: An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a positive refractive power; a second lens having one of a positive refractive power and a negative refractive power; and a third lens that corrects for aberration. At least one of the first and second lenses has a diffractive optical surface, the diffractive optical surface having twenty or less orbicular gratings in a range to pass an effective light ray.

Abstract: An optical instrument includes a grating. The grating includes a plurality of plates that form a single first plane. The instrument further includes a mirror surface positioned adjacent to the grating. The mirror surface is positioned in a second plane. In an embodiment, the mirror surface is made of a substrate, a silicon wafer positioned on the substrate, and a mirror etch pit surface on the silicon wafer.

Abstract: A light reflecting mask includes a reflecting layer which is provided on a substrate and reflects light, an absorbing layer which is provided on the reflecting layer and absorbs light, a device pattern which is formed in a first region of the absorbing layer, and a reflectance measuring pattern which is formed in a second region of the absorbing layer. The reflectance measuring pattern is a diffraction grating.

Abstract: The present invention is a diffractive optical element 1 in which mutually different materials make contact with one another via the same diffraction grating groove 30. One of the mutually different materials is a first ultraviolet curing resin 10 and the other of the mutually different materials is a second ultraviolet curing resin 20 that is different from the first ultraviolet curing resin 10.

Abstract: To operate an optical device comprising an SLM with a two-dimensional array of controllable phase-modulating elements groups of individual phase-modulating elements are delineated, and control data selected from a store for each delineated group of phase-modulating elements. The selected control data are used to generate holograms at each group and one or both of the delineation of the groups and the selection of control data is/are varied. In this way upon illumination of the groups by light beams, light beams emergent from the groups are controllable independently of each other.

Abstract: A method of placing a grating material at an optimum distance from a sensor that will produce a reference spectrum on that sensor. In a preferred embodiment of the present invention, a device with a diffraction grating end will protrude into the empty lens well of a camera and with the camera inserted into a telescope eyepiece holder will focus both a image of an object, that the telescope is pointed to, and its spectrum onto the light sensor in the camera. This dual image, called a reference spectrum, allows the separation between the image of the object and a point in the image of its spectrum to be determined quickly. This separation distance to the spectral point within the spectrum is then a referenced distance. Once a reference distance is known it is then used to determine the wavelength of any other point or spectral line within the spectrum.

Abstract: A microstructure area (201) providing a first diffractive visual effect is produced on the surface layer (240) of a paper or cardboard substrate (230) of a product (200). In addition, a bulge (206) or a recess (207) having a second microstructure area (202) is produced on the surface layer (240), wherein a doubly curved portion (203) is located between the first (201) and the second (202) microstructure areas. Said combination of the bulge (206)/recess (207), microstructure areas (201, 202) and doubly curved portion (203) makes counterfeiting of the product (200) difficult and provides a special visual effect.

Abstract: In the diffraction grating low-pass filter, the diffraction grating has a refractive index variation region having a refractive index different from that of the glass substrate and having a lattice shape in the glass substrate, and the refractive index variation region includes a plurality of phases depending on differences of optical path lengths. Furthermore, in the diffraction grating low-pass filter, a region having an array of two rows and two columns in which regions of phases 0 and 2? are arranged in one diagonal direction and regions of phases ? and 3? are arranged in the other diagonal direction is set as a unit grating.

Abstract: An optical pulse-width modifier structure includes a first diffraction grating and an optically unpowered reversing mirror. An optical path extends between the first diffraction grating and the optically unpowered reversing mirror. A second diffraction grating lies on the optical path between the first diffraction grating and the optically unpowered mirror. A set of optically powered mirrors lies on the optical path between the first diffraction grating and the second diffraction grating. The diffraction gratings and mirrors are positioned such that an input light beam is diffracted from the first diffraction grating, reflected from each of the set of optically powered mirrors, diffracted from the second diffraction grating, reflected from the optically unpowered reversing mirror back to the second diffraction grating, diffracted from the second diffraction grating, reflected from each of the set of optically powered mirrors, and diffracted from the first diffraction grating as an output light beam.

Abstract: A passive optical element is transferred into a substrate already having features with a vertical dimension thereon. The features may be another passive optical element, an active optical element, a dichroic layer, a dielectric layer, alignment features, metal portions. A protective layer is provided over the feature during the transfer of the optical element. One or more of these processes may be performed on a wafer level.

Abstract: A method and apparatus for selecting a specific fraction from a heterogeneous fluid-borne sample using optical gradient forces in a microfluidic or fluidic system are presented. Samples may range in size from a few nanometers to at least tens of micrometers, may be dispersed in any fluid medium, and may be sorted on the basis of size, shape, optical characteristics, charge, and other physical properties. The selection process involves passive transport through optical intensity field driven by flowing fluid, and so offers several advantages over competing techniques. These include continuous rather than batch-mode operation, continuous and dynamic tunability, operation over a wide range of samples, compactness, and low cost.

Abstract: Methods and structures for reducing and/or eliminating moisture penetration in an optical package. The optical package may include (1) a layer of inorganic material placed over the points of the optical package susceptible moisture penetration of the optical package; (2) a portion of hygroscopic material placed over the points of the optical package susceptible to moisture penetration; (3) a layer of hygroscopic material placed on the interior surface of the optical package; and/or (4) a layer of hydrophobic material coated on the optical surfaces of the optical package.

Abstract: Provided is a transmissive active grating device that transmits light or diffracts light according to an applied voltage. The transmissive active grating device includes: an electro optical material layer which transmits light; a first electrode formed on a bottom surface of the electro optical material layer; and an array of a plurality of second electrodes arranged on a top surface of the electro optical material layer in parallel with each other.

Abstract: The invention provides a diffractive optical element that can be used as a light beam splitter device, an optical low-pass filter or the like having a two-dimensionally multi-valued fine periodic structure. The surface of a transparent substrate for the diffractive optical element is divided into fine rectangular areas of identical shape which line up in two orthogonal directions while a plurality of rows line up with ends in alignment in any one of the directions. With respect to standard wavelength light incident vertically on the surface of the transparent substrate, an l-th, and a (l+1)-th rectangular area in an l-th row, where l is an odd number, gives a phase 2p?, and a phase {(4q+1)?/2+??/2}, respectively, and an l-th, and a (l+1)-th rectangular area in a (l+1)-th row gives a phase {(4r+3)?/2+3??/2}, and a phase {(4s+2)?/2+??}, respectively. However, ?0.25???0.25, and p, q, r, and s is an integer.

Abstract: A spill light removing device includes a first blocker which is located perpendicularly to a stream route of light being irradiated from a light source and blocks a stream of light that is incident to the surface of the first blocker, except on a hole formed on the first blocker; a pass-through tunnel which is connected to the hole and is formed in the same direction to the stream route of light and allows the stream of the light to pass through; and a second blocker which has a irregularity pattern that is formed on a inner wall of the pass-through tunnel and reflects the light that is incident in the deviated direction of the stream route of light.

Abstract: A light detecting apparatus which can be arranged even in an optical path of which converting angle is relatively large, and can accurately detect light entering along a predetermined direction in an optical path. The light detecting apparatus (10) for detecting light which enters in a predetermined direction in an optical path has a light splitting element (11) having two optical surfaces (11a, 11b) positioned in the optical path, and a photoelectric detector (12) for photo detecting light which propagates inside the light splitting element and which is guided from a side face (11c) of the light splitting element. The light splitting element further has an incident angle conversion section (13) for converting a part of light which enters one optical face of the light splitting element into light entering the other optical surface at an incident angle greater than or equal to a total reflection angle.

Abstract: Practical diffractive optical elements are made available efficiently and at low-cost. A refractive-index-modulated diffractive optical element includes a transparent DLC (diamond-like carbon) film (2) formed on a transparent substrate (1), with the DLC film (2) containing a diffraction grating having local regions (2a) of a relatively high refractive index and local regions (2) of a relatively low refractive index. The DLC film (2) can readily be deposited by plasma CVD onto the substrate (1), and the high refractive-index regions (2a) within the DLC film can readily be formed by irradiating it with an energy beam (4) such as an ion beam.

Abstract: A space variant polarization optical element for spatially manipulating polarization-dependent geometrical phases of an incident light beam. The element comprises a substrate with a plurality of zones of gratings with a continuously varying orientation. The orientation denoted by ?(x-y) is equal to half of a desired geometrical phase (DGP) modulus 2?. Each grating has a local period that is smaller than the wavelength of the incident light beam. In other embodiments of the present invention the substrate comprises a plurality of zones of gratings with a continuously varying orientation.

Abstract: Diffractive patterns are disposed on a MEMS substrate in the gaps between the MEMS micromirrors to reduce backreflection of light leaking through the gaps and reflected by the MEMS substrate. The diffractive patterns are silicon surface-relief diffraction gratings or silicon oxide gratings on silicon substrate. Sub-wavelength gratings are used to suppress higher orders of diffraction; 50% duty cycle surface relief gratings on a substrate having index of refraction close to 3 are used to suppress both reflected and transmitted zero orders of diffraction simultaneously. The gratings have lines running parallel or at a slight angle to the gaps, to prevent the diffracted light from re-entering the gaps.