Abstract: The present invention relates to an optical signal processor which can multiplex or demultiplex multiwavelength signal light. The optical signal processor includes an optical input/output capability, a first optical system, a wavelength branching capability, a second optical system, and a reflecting capability.

Abstract: Novel methods are disclosed for designing and constructing miniature optical systems and devices employing light diffractive optical elements (DOEs) for modifying the size and shape of laser beams produced from a commercial-grade laser diodes, over an extended range hitherto unachievable using conventional techniques. The systems and devices of the present invention have uses in a wide range of applications, including laser scanning, optical-based information storage, medical and analytical instrumentation, and the like. In the illustrative embodiments, various techniques are disclosed for implementing the DOEs as holographic optical elements (HOEs), computer-generated holograms (CGHs), as well as other diffractive optical elements.

Abstract: A method and an apparatus for aligning a diffraction grating align the longitudinal direction of grooves of a diffraction grating to a predetermined direction. The method and apparatus detect a diffracted light pattern sent from the diffraction grating, and displace the diffraction grating such that the direction of an arranging direction obtained from the diffracted light pattern is aligned in the predetermined direction.

Abstract: A diffraction element includes a light-transmittable member and a diffraction grating formed on at least one face of the light-transmittable member. When a first laser beam having a first wavelength &lgr;1 and a second laser beam having a second wavelength &lgr;2 are transmitted through the diffraction element at first and second diffraction efficiencies, respectively, the diffraction element functions to equalize the first and second diffraction efficiencies to each other by only the one face of the diffraction element. The diffraction grating has a first phase modulation amount ø1 for the first laser beam and a second phase modulation amount ø2 for the second laser beam and the first and second phase modulation amounts ø1 and ø2 are, respectively, approximate to (2&pgr;N1±&Dgr;ø) and (2&pgr;N2±&Dgr;ø) in which “N1” and “N2” are natural numbers and “&Dgr;ø” is a phase variation amount.

Abstract: The present invention relates to an optical device (10) and a corresponding method for (de-)multiplexing optical signals. The devices (10) comprises a multiple channel port (28), at least a first and a second separated channel port (30, 32), and a diffraction unit defining wavelength specific beam paths (46, 48) between the multiple channel port (28) and the separated channel ports (30, 32). The diffraction unit includes a diffraction grating (12) and a plurality of mirrors (16, 18) adapted for receiving and reflecting the optical beams (46, 48) from and to the diffraction grating (12.) The mirrors (16, 18) are individually angled for reflecting the optical beams (46, 48) at different angles (24) to the diffraction grating (12).

Abstract: Invisible different monochromatic images are inscribed in a diffractive optical element. Each of the images appears when a specific light source is on and image disappears when the specific light is off. The light sources for the different monochromatic images are spaced at different positions with respect to the diffractive optical element. A dynamic image is produced by time-varying and electronically controlling the intensity and on/off of the different light sources.

Abstract: A tunable filter device (10) has a plurality of input waveguide channels (141, 142, 143), a plurality of output waveguide channels (161, 162, 163) and a Bragg grating (13) which are formed in a planar waveguide (111). Every input waveguide channel couples with the Bragg grating at a different angle, and every output waveguide channel is a mirror image of a particular input waveguide channel. When input light transmits through a particular input waveguide channel, light of a particular wavelength is reflected by the Bragg grating to a corresponding, mirror image output waveguide channel.

Abstract: An objective lens unit for an optical pickup used for recording and/or reproducing information signals from an optical disc. The objective lens unit includes a resin layer (21) having, sequentially from an object side, a first surface S1 as an aspherical surface and a second surface S2 as an aspherical surface, at least one of the first surface and the second surface including a diffractive surface, and a lens of glass (22) having the second surface S2 as an aspherical surface and a third surface S3 as an aspherical surface. The lens unit is corrected for the chromatic aberration on an image surface on the optical axis with respect to the light of a reference wavelength not larger than 420 nm within several nm of the reference wavelength, with the numerical aperture of the lens unit being not less than 0.8. This objective lens unit is able to converge the laser light close to the limit of diffraction on the image surface.

Abstract: The present invention relates to a device for homogenizing the spatial intensity distribution of a spatially coherent radiation beam. The device includes a grating arranged in the propagation path of a spatially coherent radiation beam for diffracting the coherent beam and thus decreasing the coherence length of a diffracted radiation beam in a direction orthogonal to the propagation direction of the radiation beam relative to the width of the radiation beam in the orthogonal direction; and a radiation splitting and directing arrangement arranged in the propagation path of the diffracted radiation beam for splitting the diffracted radiation beam into spatially separated portions and for superimposing the spatially separated portions to form a radiation beam having a homogenized spatial intensity distribution.

Abstract: Integrated semiconductor waveguide gratings, methods of manufacture thereof and methods of apodizing thereof are described. A semiconductor waveguide grating includes a substrate, a cladding layer disposed on the substrate, a guide structure that includes a plurality of discrete transverse sections implanted with ions disposed between adjacent transverse sections substantially free of implanted ions.

Abstract: All-dielectric diffractive pigment flakes can be applied to an object to impart a diffractive effect to the object without substantially changing the background color of the object. In one case, such diffractive pigment flakes can be applied to a white object to impart a white diffractive effect. The thickness of the dielectric layers in the diffractive pigment flakes can be chosen to provide thin-film interference, as well as diffraction from the interfaces between layers patterned with a diffraction grating. In some cases, the thin-film interference can provide color shifting in addition to the diffractive effect.

Abstract: A method of fabricating an optical waveguide grating having a plurality of grating lines of refractive index variation comprises the steps of: (i) repeatedly exposing a spatially periodic writing pattern onto a photosensitive optical waveguide: and (ii) moving the writing light pattern and/or the waveguide between successive exposures of the writing light pattern, so that each of at least a majority of the grating lines is generated by at least two exposures to different respective regions of the writing light pattern.

Abstract: The invention is directed to metal-free grating for use in wavelength optical communications, and in particular to metal-free, reflective immersed diffraction gratings. The gratings of the invention area made of at least a first material 1 of refractive index n1 and a second material of refractive index n2. Materials 1 and 2 must obey the Expressions: (I) n1>n2, (II) n1>&lgr;/2L>n2 for single diffracted order at Littrow, and (III) n2/n1<Sin|&thgr;j|<1; wherein &lgr; is the wavelength of the light incident on the grating, &thgr;j represents any and all propagation angles of incident and diffracted light, and L is the grating period. The grating profile is located at the interface of material 1 and to material 2. In one embodiment, the grating profile is made from additional material 3 and 4 of refractive index n3 and n4, respectively, and is placed between materials 1 and 2. In another embodiment the grating is made from silicon.

Abstract: Imaging system for a microscope based on extreme ultraviolet (EUV) radiation. The present invention is directed to a reflective imaging system for an x-ray microscope for examining an object in an object plane, wherein the object is illuminated by rays of a wavelength of less than 100 nm, particularly less than 30 nm, and is imaged in a magnified manner in an image plane. In the imaging system, according to the invention, for a microscope based on extreme ultraviolet (EUV) radiation with wavelengths in the range of less than 100 nm, with a magnification of 0.1× to 1000× and a structural length of less than 5 m, at least one of the imaging optical elements 2 and 3 in the beam path has a diffractive-reflective structure which is arranged on a spherical or plane area and has a non-rotationally symmetric, asymmetric shape. The arrangement according to the invention provides an imaging system which avoids the disadvantages of the prior art and ensures a high imaging quality.

Abstract: A grating that includes a multilayer structure that has alternating layers of materials, a plurality of grooves formed between a plurality of lands, wherein at least one structural parameter of the plurality of grooves and plurality of lands is formed randomly in the multilayer structure.

Abstract: A security element is embedded in a layer composite of plastic material and has reflecting, optically variable surface patterns which can be visually recognized from predetermined observation directions and which are formed from a mosaic of surface elements occupied by optically active structures. A part of the surface pattern is additionally covered by a regularly arranged matrix of unit cells. Each unit cell is occupied by a single elementary surface or a group of identical surface portions that contain optically active structures which are independent of the mosaic of the surface pattern. The arrangement of the elementary surfaces and the surface portions in the matrix form an item of concealed information which is not perceptible to the naked eye, in the form of graphic or alphanumeric characters which however are reproduced in a color photocopy with a color or gray value contrast which is perceptible to the naked eye.

Abstract: A method and apparatus for laterally deflecting and/or separating a flow of particles using a static array of optical tweezers. In an array of optical tweezers with a lattice constant larger than the size of a particle of interest, particles driven past the array by an external force experience an additional interaction with the array of traps. By altering the angle of the array of traps relative to the external force, the particles' movement from trap to trap inside the array can be biased away from the direction of the external force, thereby enabling selective deflection and/or separation of particles.

Abstract: The present invention relates to a prism diffuser for diffracting and spreading light, and in particular to a prism diffuser for diffracting and spreading light which is capable of spreading light in a certain direction at a wider angle based on a structure combined with a prism capable of diffracting light on a surface of a medium formed of a glass which transmits or reflect light, a film formed of a transparent synthetic resin material or a metallic plate and a diffuser capable of spreading light and diffracting, spreading and transmitting light into two directions or diffracting, spreading and reflecting light in one direction.

Abstract: A dispersion compensator having relatively uniform transmission characteristics over the bandwidth of a communication channel. The compensator is designed to process an optical signal corresponding to the communication channel by decomposing that signal into spectral components, routing different components along different optical paths that impart relative delays between the components, and recombining the delayed components spatially and directionally to generate a processed optical signal with reduced chromatic dispersion. In one embodiment, the compensator includes a diffraction grating optically coupled to a mirror array, in which different mirrors receive light corresponding to different communication channels. For each channel, a desired group delay value is produced by selecting the curvature of the corresponding mirror. A compensator employing independently addressable, variable-curvature mirrors enables generation of variable, channel-specific group delays.

Abstract: An aberration compensating optical element includes: a diffractive structure having a plurality of ring-shaped zone steps formed into substantially concentric circles on at least one surface of the aberration compensating optical element; wherein the aberration compensating optical element is adapted for being disposed on an optical path between a light source for emitting a light having a wavelength of not more than 550 nm, and an objective lens made of a material having an Abbe constant of not more than 95.

Abstract: A methods and apparatus for labeling an item using diffraction grating-based encoded optical identification elements 8 includes an optical substrate 10 having at least one diffraction grating 12 disposed therein. The grating 12 has one or more colocated pitches &Lgr; which represent a unique identification digital code that is detected when illuminated by incident light 24. The incident light 24 may be directed transversely from the side of the substrate 10 (or from an end) with a narrow band (single wavelength) or multiple wavelength source, and the code is represented by a spatial distribution of light or a wavelength spectrum, respectively, or a combination thereof. The element 8 can provide a large number of unique codes, e.g., greater than 67 million codes, and can withstand harsh environments.

Abstract: An optical device includes a planar subwavelength grating (10) formed in a dielectric material and having a laterally varying, continuous grating vector. When used to modulate a beam of laterally uniform polarized electromagnetic radiation incident thereon, the device passes the incident beam with a predetermined, laterally varying transmissivity and/or retardation. When used to effect polarization state transformation, the device transforms a beam of electromagnetic radiation incident thereon into a transmitted beam having a predetermined, laterally varying polarization state. The device (214) can be used to provide radially polarized electromagnetic radiation for accelerating subatomic particles or for cutting a workpiece. The device (108) also can be used, in conjuction with a mechanism for measuring the lateral variation of the intensity of the transmitted beam, for measuring all four Stokes parameters that define the polarization state of the incident beam.

Abstract: A diffractive optical element including a stack of first, second and third optical regions or a stack of first, second, third and fourth optical regions, a first relief pattern formed between the first and second optical regions, and a second relief pattern formed between the second and third or between the third and fourth optical regions. The first and second relief patterns have substantially identical pitch distributions and are substantially aligned in a direction of an optical axis. Depths of the first and second relief patterns are set such that a wavelength dependency of diffraction efficiency can be decreased over a wavelength range to be used. It is possible to manufacture in a simple manner at a low cost a diffractive optical element in which undesired flares and ghosts are suppressed.

Abstract: In accordance with the invention, an article comprising a nanoscale surface pattern, such as a grating, is provided with a nanoscale patterns of reduced edge and/or sidewall roughness. Smooth featured articles, can be fabricated by nanoimprint lithography using a mold having sloped profile molding features. Another approach uses a mold especially fabricated to provide smooth sidewalls of reduced roughness, and a third approach adds a post-imprint smoothing step. These approaches can be utilized individually or in various combinations to make the novel articles.

Abstract: The present invention provides a different optical element having superior optical characteristics. A polycrystalline substrate having crystal grains whose sizes are not more than 1 &mgr;m or an amorphous phase at the dry-etched surface thereof, or an upper film layer 8 formed on a polycrystalline substrate 1 being the same materials as that of the polycrystalline substrate 1, which has finer crystal grains than-those of the substrate. The upper film layer 8 is dry etched, and AR coat 6 is formed thereon.

Abstract: In a diffraction element, a diffraction grating is formed with a grating pitch having different diffraction angles in accordance with a wavelength of a laser light beam incident thereon. The wavelength is variable in accordance with an environment temperature. The diffraction element is made of a material having a linear expansion coefficient which causes thermal variation in the grating pitch enough to compensate at least a part of the diffraction angle variation due to environment temperature change.

Abstract: The invention is directed to metal-free grating for use in wavelength optical communications, and in particular to metal-free, reflective immersed diffraction gratings. The gratings of the invention area made of at least a first material 1 of refractive index n1 and a second material of refractive index n2. Materials 1 and 2 must obey the Expressions: (I) n1>n2, (II) n1>&lgr;/2L>n2 for single diffracted order at Littrow, and (III) n2/n1<Sin |&thgr;j|<1; wherein &lgr; is the wavelength of the light incident on the grating, &thgr;j represents any and all propagation angles of incident and diffracted light, and L is the grating period. The grating profile is located at the interface of material 1 and to material 2. In one embodiment, the grating profile is made from additional material 3 and 4 of refractive index n3 and n4, respectively, and is placed between materials 1 and 2. In another embodiment the grating is made from silicon.

Abstract: The invention relates to an element for the combined symmetrization and homogenization of a beam of rays and to a method for designing an element of this type.

Abstract: A display system includes a diffraction grating that generates exit-pupil images, where one of the exit-pupil images has a first intensity and the remaining exit-pupil images each have or approximately have a second intensity that is less than the first intensity. The system also includes a filter that attenuates the intensity of the one exit-pupil image. In one example, the filter attenuates the 0th-order exit-pupil image so that all of the exit-pupil images have the same or approximately the same intensities.

Abstract: A diffraction grating providing reduced polarization dependent loss. The elements of pixels of the diffraction grating are fixed or actuated such that some grating elements are actuated to correspond to a positive polarization dependent loss and others are actuated to correspond to a negative polarization dependent loss. The pixels may include multiples of three grating elements or multiples of four grating elements. An electrostatic beam structure providing increased actuation in a direction away from a substrate may be used in a diffraction grating providing reduced polarization dependent loss.

Abstract: An optical wavelength selection device containing an optical beam source, a device for collimating the optical beam to produce a collimated optical beam, a diffraction grating assembly for diffracting the collimated optical beam to produce a collimated optical diffracted beam, a device for modifying the polarization state of the collimated optical beam, and a lens assembly for focusing the collimated optical diffracted beam. The device for modifying the polarization state of the collimated optical beam is located within the diffraction grating assembly in one embodiment and before the diffraction grating assembly in another embodiment.

Abstract: A diffractive optics system for wavelength division multiplexing and demultiplexing optical signals. The present system can be employed in multiplexers, demultiplexers, spectrum analyzers, and the like. In one embodiment, the diffractive optics system includes a waveguide array, a lens assembly, first and second diffractive optical elements (“DOEs”), and a reflector. In a demultiplexing operation, a multiplexed optical signal is input into the system via an input waveguide in the waveguide array. The signal is focused by the lens assembly, then transmitted through the first and second DOEs, where diffraction of the signal and separation of its constituent wavelength-distinct channels occurs. The channels are then reflected by the reflector back through the first and second DOEs, after which each channel is directed by the lens assembly to one of a plurality of output waveguides located in the waveguide array. A conversely similar process is followed for producing a multiplexed optical signal.

Abstract: A transmitted type diffractive optical element comprises a transparent plate made of a material having a refractive index n2, whereas the transparent plate is in contact with a medium having a refractive index n1. A number of projections are arranged with a period L on the first surface side of the transparent plate. Each projection has a rectangular cross section with a height H and a width W. An antireflection layer is formed on the second surface of the transparent plate. When the light L1 having a wavelength &lgr; is incident on the first surface at an incident angle &thgr;, the transmitted type diffractive optical element satisfies (2n1L/&lgr;)sin &thgr;=1, and n2/n1≦3 sin &thgr;, whereas each of the diffraction efficiencies of transmitted first-order diffracted light L31 in TE and TM polarization modes is at least 0.8.

Abstract: A wavefront measurement system has a source of electromagnetic radiation. An imaging system focuses the electromagnetic radiation at an object plane. A first grating is positioned in the object plane and has a plurality of rulings with randomized height. A stage moves the first grating parallel to the rulings. A projection optical system projects an image of the first grating onto an image plane. A second grating is at the image plane. A detector behind the second grating receives a fringe pattern produced by the second grating.

Abstract: A plastic lens includes refractive and diffractive optical apparatus configured to produce optothermal changes substantially canceling each other over a predetermined working temperature range to render the plastic lens substantially athermalized over the range.

Abstract: An electromagnetic radiation diffuser, operative at extreme ultraviolet (EUV) wavelengths, is fabricated on a substrate. The diffuser comprises a randomized structure having a peak and valley profile over which a highly reflective coating is evaporated. The reflective coating substantially takes the form of the peak and valley profile beneath it. An absorptive grating is then fabricated over the reflective coating. The grating spaces will diffusely reflect electromagnetic radiation because of the profile of the randomized structure beneath. The absorptive grating will absorb the electromagnetic radiation. The grating thus becomes a specialized Ronchi ruling that may be used for wavefront evaluation and other optical diagnostics in extremely short wavelength reflective lithography systems, such as EUV lithography systems.

Abstract: An optical arrangement has a light source which emits coherent light of a specific wavelength. Further provided is an optical Littrow grating, arranged at a specific Littrow angle &thgr;L. It has a multiplicity of parallel diffraction structures following one another periodically at an interval in each case of one specific grating period and arranged on a substrate predetermining a base area. The light wavelength, the grating period and the Littrow angle &thgr;L are tuned to one another in such a way that the grating is used in one of the largest diffraction orders m for light reflected back at the Littrow angle &thgr;L, which still fulfils the condition: (2(m+1)/m−1) sin (&thgr;L)≧1 An optical arrangement of this kind has an increased reflection efficiency.

Abstract: New grating structures include a bonded transmission grating structure. The grating structure is encapsulated by two pieces that are bonded together. In addition, a new method of making grating structures includes forming wells with an aspect ratio (depth:width) of at least 3:1, 7:1 or greater. Such grating structures can be used to form gratings with high diffraction efficiencies for both TE and TM polarizations of light.

Abstract: A method for manufacturing a diffusion grating-based optical identification element is provided. The optical identification element includes a known optical substrate, having an optical diffraction grating disposed in the volume of the substrate. A large number of substrates or microbeads having unique identification codes can be manufactured winding a substrate, such as a fiber, around a polygonal shaped cage/basket to form a fiber ribbon having flat sections. A grating writing station writes one or more gratings into each flat section to form a unique code to this section. Each flat section of fibers of the fiber ribbon is written with the same gratings to provide the same identification code, or alternatively each flat section may be have a different grating(s) written therein so that each section has a different identification code. The fiber ribbon is then removed from the cage and diced to form a groups of optical identification elements, each group having unique optical identification codes.

Abstract: In a diffractive optical element, which is formed by laminating at least three layers of diffraction gratings made of at least three kinds of materials which differ in dispersion, at least three design wavelengths are set.

Abstract: A two layer system can transform an arbitrary specified light field at an input plane to a desired light field at an output plane. The light field includes both intensity and phase. Such a system can be cascaded for higher level functionality. There are two computations involved. The first computes a sensitivity matrix symbolically. The elements of the matrix hold the variation in each element at the output plane with variation in each element of both phase screens. An element of this matrix is provided for reference. The second algorithm iteratively updates the phase screen values to bring the output field to that desired. On each iteration, the algorithm performs a forward computation from input to output. The phase values are updated using the sensitivity matrix and the error at the output relative to that desired.

Abstract: A diffractive optical element for guiding a light having a color spectrum characterized by a plurality of wavelengths longer than a shortest wavelength, &lgr;B, and shorter than a longest wavelength, &lgr;R, the light striking the diffractive optical element at an angle greater than a first field-of-view angle, &agr;−FOV, and smaller than a second field-of-view angle, &agr;+FOV. The diffractive optical element comprising a linear grating being formed in a light-transmissive substrate. The linear grating is characterized by a pitch, d, selected so as to allow total internal reflection of a light having wavelength of &lgr;B and a striking angle of &agr;−FOV. The light-transmissive substrate is characterized by an index of refraction, ns, larger than a minimal index of refraction, nMIN, which is selected so as to allow total internal reflection of a light having wavelength of &lgr;R and a striking angle of &agr;+FOV.

Abstract: An electro-mechanical grating device including: a base having a surface; a bottom conductive layer provided above said base; a spacer layer is provided and a longitudinal channel is formed in said spacer layer, wherein said spacer layer defines an upper surface and the channel having a first and a second opposing side wall and a bottom; a plurality of spaced apart ribbon elements disposed parallel to each other and spanning the channel, said ribbon elements are fixed to the upper surface of the spacer layer on each side of the channel and each of the ribbon elements is provided with a conductive layer; a mechanical stop provided between the bottom conductive layer and the bottom of the channel wherein the mechanical stop forms a rigid barrier that is separated from a lower ribbon surface of the ribbon elements by a distance h0.

Abstract: The present invention provides a scanning device with the following features: the system is capable of writing data to record carriers of a first format because it is corrected for chromatic aberration resulting from fast wavelength variations during write operation; it has a diffractive element with a generally sawtooth-like pattern, such that it may for example be manufactured in a single-step replication process; the system has high efficiency for scanning first optical record carriers (e.g. DVDs) and acceptable efficiency for scanning second optical record carriers (e.g. CDs); and the lens provides limited spherochromatism and the system is thus able to cope with wavelength variations.

Abstract: A light guide plate has a hologram pattern on a light exit surface. The hologram pattern anisotropically diffuses light in the direction parallel with a light incident surface of the light guide plate. On a back surface of the light guide plate are formed mirror-polished prism structures extending parallel with the light incident surface. A downward-pointing prism sheet with a given prism apex angle is placed on the light exit surface of the light guide plate. The use of the downward-pointing prism sheet together with the light guide plate having the anisotropic diffusion hologram pattern integrally formed thereon produces a liquid crystal display device with enhanced luminance properties.

Abstract: The invention relates to an optical device (50) for manipulating a light wave (&lgr;) using a diffractive grating structure (G). According to the basic idea behind the invention a prior art type diffractive grating structure having a permanently shaped surface relief is substituted with an electrically deformable diffractive grating structure (G), where a preformed, basic surface relief of the grating is composed of dielectric and deformable viscoelastic material, which can be electrically and sequentially fine tuned in shape to adjust the diffraction properties of said grating individually for different wavelengths. The invention permits manufacture of virtual display devices with a significantly larger exit pupil diameter than prior art solutions without degrading the color uniformity of the display device.

Abstract: A light modulator has one or more gratings and one or more MEMS actuators operable to move the gratings for selectively modulating light from an input light source. Certain embodiments have a plurality of blazed gratings arranged parallel to a plane and movable linearly parallel to the plane by MEMS actuators. Each of the gratings is individually blazed for light of a selected color such as red, green or blue. Associated with the gratings may be portions providing black and/or white outputs. An aperture spaced apart from the plane allows color(s) selected from an input white-light source to be directed to an output. An array of MEMS-actuated modulation devices provides a color spatial light modulator. Other embodiments have a grating adapted to be tilted by a MEMS actuator, either continuously through a range of angles or to a selected angle of a set of predetermined discrete angles, to direct selected wavelengths diffracted by the grating toward collection optics for a modulated light output.

Abstract: A system and method are provided for writing refractive index structures, such as gratings, in an optical waveguide. There is no requirement for structures having interferometric stability of the control elements. The method includes providing first and second light beams, the first beam having a first polarization state and a first wavevector, the second beam having a second polarization state different from the first polarization state, and a second wavevector different from the first wavevector. The method also includes illuminating a diffractive optical element by at least a part of the first beam and a part of the second beam so as to diffract parts of the first and second beams, and positioning the medium in relation to the diffractive element so as to illuminate the first part of the medium by the diffracted parts of the first and second beams.

Abstract: The present invention provides a production process of, duplication plate material for duplication of, and medium provided with an optically diffractive structure such as a hologram and diffraction grating having excellent optically diffractive effect, wherein the optically diffractive structure has a surface configuration having plural corrugation-like convexo-concave shapes, and the convexo-concave shapes of the final medium is formed by using a duplication plate material. The convexo-concave shapes of the duplication plate material have a cross-sectional surface which is crosswise to the peaks of the convexo-concave shapes, and a salient section defined by a salient line and a middle line has a smaller area than that of an adjacent reentrant section defined by a reentrant line and the middle line. Herein, the middle line is drawn by connecting midpoints of the height of the convexo-concave shapes.

Abstract: A material measure in the form of an amplitude grating including a first reflecting layer, a second transparent layer and a third layer, which is partially transparent to light, the third layer comprising a measuring graduation, wherein the second layer is arranged between the first layer and the third layer.