Abstract: Novel optical devices, which are referred to as composite prisms in this document, have been designed, produced and tested. They have the potential to be useful for a number of vision related applications. For high prism diopter (15 prism diopters or more), composite prisms have resulted in thinner, lighter and lower aberration optical devices than the standard ophthalmic prisms currently in use. They also offer significantly better optical quality than the Fresnel press-on prisms which are also used to correct several ophthalmic disorders.

Abstract: A method of manufacturing a diffractive optical element, including a process for forming a resist mask of blazed shape upon a substrate and for etching the substrate by use of the resist mask so that the blazed shape is transferred to the substrate. The method includes a process for forming, before the etching, an element being effective to prevent a taper shape, to be produced at an edge of the blazed shape of the resist mask, from being transformed to the substrate.

Abstract: A security element (2) comprising a plastic laminate (1) has a surface pattern which is composed mosaic-like at least from surface elements, wherein in the surface elements a reflecting interface (8) between a shaping layer (5) and a protective layer (6) of the plastic laminate (1) forms optically effective structures (9). Light (11) which is incident on the plastic laminate (1) and which passes through a cover layer (4) of the plastic laminate (1) and through the shaping layer (5) is deflected in a predetermined manner by means of the optically effective structures (9). Shaped in the surface of at least one of the surface elements is a diffraction structure which is produced by a superimposition of a linear asymmetrical diffraction grating (24) with a matt structure. The linear asymmetrical diffraction grating (24) has a spatial frequency from the range of values of between 50 lines/mm and 2,000 lines/mm.

Abstract: A diffractive element used in conjunction with a grating to move a desired order beam off-axis, thereby reducing interference by undesired orders. Use of the off-axis grating allows a more uniform beam in the presence of manufacturing defects, such as etch depth errors. The diffractive element used with the off-axis grating may include a beam shaper, a one-dimensional beam splitter, or a two-dimensional beam splitter.

Abstract: The present invention provides the beam-shaping device which includes a first surface on which is formed a first grating through which a beam of light emitted from a light source on an optical axis passes; and a second surface on which is formed a second grating through which the beam of light having passed through the first surface passes; wherein the first grating and the second grating are designed, so as to maintain, when the wavelength of the emitted beam of light varies, a prescribed relationship between (1) the displacement of the first virtual light emitting point, in the first meridian plane containing the optical axis, and (2) the displacement of the second virtual light emitting point, in the second meridian plane perpendicular to the first meridian plane containing the optical axis.

Abstract: A liquid-crystal lens includes a hologram liquid-crystal element having a liquid crystal which provides a light beam transmitting therethrough with a phase change so as to have a wavefront of a blaze-hologram shape; and a segment liquid-crystal element including a first electrode divided correspondingly to the blaze-hologram shape, a second electrode opposed to the first electrode and a liquid crystal for providing the transmitting light beam with a phase change by voltage application to the first and second electrodes, the segment liquid-crystal element being arranged coaxial to the hologram liquid-crystal element.

Abstract: Disclosed is a diffractive optical element which is made of at least two materials of different dispersions and which includes at least two diffraction gratings being accumulated one upon another, wherein each diffraction grating is formed on a curved surface of a substrate, and wherein a diffraction grating, of the at least two diffraction gratings, in which a curvature radius of the curved surface and a curvature radius of a grating surface in a portion where a grating pitch is largest, have different signs, is one of the at least two diffraction gratings which has a smallest grating thickness.

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: An optical element including a binary blaze grating formed thereon, wherein the binary blaze grating is formed so as to have step differences formed by a number of levels produced by mechanical processing. The number of levels is equal to or more than 5 and the height of the step difference is greater than or equal to 1 ?m.

Abstract: A diffraction grating for optical communication is disclosed. The diffraction grating includes a substrate and a reflective material adjacent the substrate, wherein one or more input optical signals incident the reflective material is diffracted into one or more output optical signals over a wavelength range of at least approximately 30 nm, within which the diffraction grating is substantially polarization insensitive.

Abstract: A plane diffraction grating based on surface normal rotation according to the present invention is designed so that the profile of the grooves at a radial area is determined depending on a rotational position of the area about a rotational center defined as a foot of the rotational axis on the surface of the plane diffraction grating. An optical system such as a spectrometer or a monochromator according to the present invention uses such a plane diffraction grating, and requires a special arrangement. The optical system includes: a plane diffraction grating as described above; a mechanism for rotating the plane diffraction grating about the rotational axis; an incidence optical system for casting a converging beam of light on a point of the surface of the plane diffraction grating, where the point is set apart from the rotational center.

Abstract: A reflection type diffraction grating according to the present invention has a structure in which a metal film as a first layer with reflectance not lower than 30% with respect to the wavelength of incident light and a transparent dielectric film as a second layer are laminated successively on the surface of the reflection type diffraction grating. With respect to the wavelength of incident light, the metal film has a refractive index selected to be not higher than 1.5 and an extinction coefficient selected to be not smaller than 6.0. The transparent dielectric film has a refractive index selected to be in a range of from 1.30 to 1.46, both inclusively, with respect to the wavelength of incident light and has an optical film thickness selected to be in a range of from 0.20? to 0.38?, both inclusively, when ? is the wavelength of incident light.

Abstract: Electromagnetic waves in wide frequency ranges up to photonics have been used for applications to time-domain imaging (TDI). Realistic time domain imaging requires a rapid optical delay line on the order of 100 ps with sampling rate at least 100 Hz. Present available optical time delay systems suffer either from low sampling rate or low time delay length, deviating from ideal requirements. The purpose of this invention is to introduce a miniature and rapid scanning optical delay line based on micro-opto-electro-mechanical system (MOEMS) technology to improve the data acquisition in time domain imaging, capable of sampling rate beyond 100 Hz and time delays beyond the 100 ps.

Abstract: A diffractive optical element includes a first layer having a relief-type grating, a second layer having a relief-type grating, and a third layer having a relief-type grating. The first, second and third layers are formed of different materials. The diffractive optical element has at least three diffraction optical parts in the boundary areas of the respective layers. The diffractive optical element is set so that at least wavelengths, the diffraction efficiency thereof for diffracted light of a predetermined order may be maximum. The three wavelengths are substantially coincident with the main wavelengths of the three primary colors.

Abstract: A method is desribed for controlling the pass band of an optical device wherein a phase mask is introduced to modify the shaped of an image produced by the photonic device.

Abstract: An extreme ultraviolet (EUV) lithography system may include a spectral purity filter including diffractive gratings. The diffractive gratings may be formed in a silicon substrate using anisotropic etching techniques to produce smooth, flat facets defined by (111) crystallographic planes.

Abstract: A diffractive optical element has a diffraction grating formed by periodic depressions and projections on the surface of a substrate and a dielectric multilayer film on the diffraction grating. The materials of the respective layers of the film are chosen such that the depth of the depressions is an integral multiple of the sum of the thickness of the layers in one period of the film. As a result, individual layers of the film are continuous across multiple depressions and projections, to provide improved first-order reflectance.

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 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: 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 multilevel optical phase element is illuminated with a light source having a plurality of wavelengths of interest. The multilevel phase element disperses light from the light source by diffraction and focuses the dispersed light onto an imaging plane. A light modulating display in the imaging plane having a plurality of pixel elements is actuated. Each pixel element is assigned to transmit a predetermined spectral region within the near field region of the multilevel display element so as to receive the dispersed and focused light from the multilevel optical phase element. A system for displaying a color image includes a light source emitting a plurality of wavelengths of interest, a multilevel optical phase element, and a light modulating electronic display.

Abstract: An optical system includes a diffractive optical element having a diffraction grating provided, on a lens surface having a curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis. The sign of the curvature of the lens surface having the diffraction grating provided thereon is the same as the sign of a focal length, at a design wavelength, of a system composed of, in the optical system, a surface disposed nearest to an object side to a surface disposed immediately before the lens surface having the diffraction grating provided thereon, and is different from the sign of the distance from the optical axis to a position where the center ray of an off-axial light flux enters the lens surface having the diffraction grating provided thereon. Further, the apex of an imaginary cone formed by extending a non-effective surface of the diffraction grating is located adjacent to the center of curvature of the lens surface having the diffraction grating provided thereon.

Abstract: A Littrow grating (1) comprises a multiplicity of parallel diffraction structures (3) succeeding one another periodically. The latter are arranged on a support (2) defining a base area (4). A diffraction structure (3) comprises a blaze flank (5) inclined towards the base area (4) substantially at the Littrow angle (&dgr;). In addition the diffraction structure (3) comprises a counter-flank (6) which forms with the blaze flank (5) at the apex of a diffraction structure (3) an apex angle (&agr;) which is less than 90°. The counter-flank (6) comprises at least two substantially plane area sections (7, 8). The latter extend, bordering one another and inclined relative to one another through an angle of inclination (&bgr;), parallel with the extension direction of the diffraction structure (3). Due to the inclination of the at least two area sections (7, 8) relative to one another, the counter-flank (6) exhibits all in all a concave surface viewed from the light incidence side.

Abstract: A lithographic illuminator to illuminate a reticle to be imaged with a range of angles is provided. The illumination can be employed to generate a pattern in the pupil of the imaging system, where spatial coordinates in the pupil plane correspond to illumination angles in the reticle plane. In particular, a coherent synchrotron beamline is used along with a potentially decoherentizing holographic optical element (HOE), as an experimental EUV illuminator simulation station. The pupil fill is completely defined by a single HOE, thus the system can be easily modified to model a variety of illuminator fill patterns. The HOE can be designed to generate any desired angular spectrum and such a device can serve as the basis for an illuminator simulator.

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 first diffractive optical element pattern with a pattern pitch that is no greater than a wavelength of incident light is formed on a first main surface of substrate such as a glass plate. Second diffractive optical element patterns are formed at positions that are respectively incident to positive first-order diffracted light and negative first-order diffracted light produced by the first diffractive optical element pattern. Negative first-order diffracted light produced by each second diffractive optical element pattern is incident upon a boundary face of the substrate at an angle that is smaller than the critical angle, and so exits the substrate.

Abstract: A diffractive optical element has a plurality of diffraction structures for a certain wavelength. These each have a width measured in the plane of the diffractive optical element and a height measured perpendicularly thereto. The widths and the heights of the diffraction structures vary over the area of the diffractive optical element. An optical arrangement comprising such a diffractive optical element has, in addition, a neutral filter. The efficiency of such a diffractive optical element and of such an arrangement can be optimized locally for usable light.

Abstract: An objective lens for recording information on and/or reproducing information from and optical information recording medium, comprises a diffractive structure including ring-shaped diffractive zones on at least one surface thereof. The objective lens is a single lens made of plastic material, at least on surface thereof is an aspheric surface, and the following conditional formula is satisfied; NA≧0.7 where NA represents an image side numerical aperture necessary for recording on and/or reproducing from an optical information recording medium.

Abstract: A light dispersing device for dispersing a polychromatic input beam into a plurality of narrow-band output beams such that the output beams are directed in a wavelength dependent manner and such that the directions of the output beams are less affected by a change in temperature. The preferred embodiment of the device comprises a diffraction grating mounted to a surface of a prism. The grating and prism have dispersing characteristics that make the output of the device substantially insensitive to a change in temperature. In one embodiment, the device is adapted to reduce the angles between the input beam and the output beams at the grating, and thereby improve throughput efficiency.

Abstract: A grating structure with a dielectric coating is disclosed that operates efficiently away from the blaze angle in low order with a high diffraction efficiency and high wavelength dispersion. Such grating structure can be employed in Littrow configuration to provide, for example, cavity feedback in excimer lasers.

Abstract: A lens system includes a lens, a grating and a non-periodic phase structure. The lens system is a-thermalised by a compensation of the temperature-dependence of the spherical aberration of the lens by the temperature-dependence of the spherical aberration of the non-periodic phase structure and the grating. The lens system is also a-spherochromatised by a compensation of the wavelength-dependence of the spherical aberration of the grating by the wavelength-dependence of the spherical aberration of the non-periodic phase structure.

Abstract: A diffractive optical element for white light is composed of a plurality of layers of optical materials and has a relief pattern constituting a diffraction grating formed at least at one cementing interface between the two different optical materials. The grating height of the relief pattern constituting the diffraction grating is defined by the following formula: h=&lgr;/|n−n′| where h represents the grating height of the relief pattern constituting the diffraction grating; &lgr; represents the wavelength (here it is assumed that &lgr;≦450 (nm)); n represents the refractive index of the optical material abutting the interface from the object side for light of the wavelength &lgr;; and n′ represents the refractive index of the optical material abutting the interface from the image side for light of the wavelength &lgr;.

Abstract: A light modulator includes elongated elements arranged parallel to each other and suspended above a substrate. The light modulator operates in a first diffraction mode and in a second diffraction mode. In the first diffraction mode, an incident light diffracts into a single diffraction order. Each of the elongated elements comprises a central blazed portion, a first outer blaze transition, and a second outer blaze transition. The central blaze portion, couples the first outer blaze transition to the second outer blaze transition. Each of the central blazed portions comprises a reflective surface. Selected ones of the central blazed portions comprise a first conductive element. The first outer blaze transition and the second outer blaze transition are coupled to the substrate.

Abstract: An optical signal processing apparatus has a diffraction grating element, first condenser lens, Faraday rotation elements, polarization beam splitter, &lgr;/2 plate, second condenser lens, third condenser lens, and diffraction grating element. The magnitude of a magnetic field of each of the Faraday rotation elements is controlled on the basis of an externally input control signal. The rotation angle of the plane of polarization of signal light is set to 0 or &lgr;/2 in accordance with the magnitude of the magnetic field. Each Faraday rotation element receives signal light having wavelengths &lgr;1 to &lgr;4, which has arrived from the first condenser lens, and outputs the signal light as a polarized light component in the first azimuth (parallel to the z-axis direction) or second azimuth (parallel to the y-axis direction).

Abstract: An objective lens for an optical pick-up has a refractive lens element provided with a diffraction lens structure on at least one surface thereof. The diffraction lens structure has a plurality of annular zones. The objective lens is capable of converging at least two beams having different wavelengths on at least two types of optical discs having different data recording densities, respectively. The objective lens is partitioned into a common area through which a beam with a low NA passes, and an exclusive high NA area which is designed to converge a beam with a high NA. The boundaries of the annular zones formed on the exclusive high NA area are designed independently from boundaries obtained from an optical path difference function so that the beam with the high NA is converged substantially on a certain point and the beam with the low NA is diffused.

Abstract: A diffraction optical element is configured such that a plurality of annular zones having minute steps extending in a direction of the optical axis therebetween are formed on a base element. The plurality of annular zones include narrow and wide zones respectively satisfying conditions (1) and (2): &Dgr;Z(i)<(1/2)·&Dgr;E(i)  (1), and &Dgr;Z(i)>(3/2)·&Dgr;E(i)  (2), wherein, i represents the order of the steps counted from the optical axis, &Dgr;E(i) represents an absolute value of an OPD provided by the i-th step, and &Dgr;Z(i) represents an absolute value of a difference between OPDs provided, with respect to a base curve, by an inner side end portion and outer side end portion of an annular zone between an i-th step and (i+1)-th step.

Abstract: A diffractive optical element includes a plurality of laminated diffraction grating surfaces. Each of the diffraction grating surfaces is formed to have a sufficiently small grating thickness as compared with a grating pitch thereof.

Abstract: An optical element has diffractive grooves. Each diffractive groove includes a first surface approximated by a predetermined optical function; a second surface extending in a direction to cross the first surface and being parallel to the optical axis; and a third surface to connect the first surface and the second surface. A width of the third surface in the direction perpendicular to the optical axis is 0.5% to 15% of the sum of a width of the first surface in the direction perpendicular to the optical axis and the width of the third surface in the direction perpendicular to the optical axis.

Abstract: A diffuser is disclosed which transmits or reflects incident light into a specific range of angles. In a preferred embodiment, this light is uniformly scattered throughout a cone of angles. The diffuser consists of two parts. The first part diffracts or reflects light into a specific offset angle. The second part, in the preferred embodiment, uniformly scatters the light through a range of angles, which is centered on the offset angle. The diffusers have utility in applications such as screens for wrist watches, computers, calculators, and cell phones.

Abstract: A light emitting device in accordance with an embodiment of the present invention includes a diffractive optical element, a first light emitting diode emitting first light having a first range of wavelengths, and a second light emitting diode emitting second light having a second range of wavelengths. The first light is directed onto the diffractive optical element at a first range of angles of incidence, and the second light is directed onto the diffractive optical element at a second range of angles of incidence. The diffractive optical element diffracts at least a portion of the first light and at least a portion of the second light into the same range of angles of diffraction to obtain light having a desired range of wavelengths. A light emitting device in accordance with an embodiment of the present invention can efficiently mix the outputs of two or more light emitting diodes to form a substantially uniform output of, for example, white light.

Abstract: An image reading system includes an imaging optical system for forming an image of an object, the optical system including at least one refractive lens and a diffractive grating blazed at a predetermined wavelength, an aperture stop positioned close to the diffractive grating, main image sensors for receiving the images of respective color components, and a flare compensating unit for compensating the image signals input from the main image sensors to eliminate flare components due to unnecessary order diffractive light.

Abstract: A diffractive optical element acts as a lens. The optical element has a diffraction grating. The diffractive grating is provided with a plurality of ridges. Each of the ridges has a transmissive surface. A sectional profile of the transmissive surface is composed of a plurality of successively connected strait lines of an identical length. The length varies from one ridge to another.

Abstract: In a lens system having one or a plurality of diffracting surfaces and one or a plurality of refracting surfaces, a power of each surface and a distance between the surfaces are set such that an optical characteristic of the lens system, such as a focal length (focal point) and/or a spherical aberration, remains substantially unvarying relative to temperature variations within a predetermined range and that an achromatic effect is substantially attained for the focal length (focal point) and/or the spherical aberration within a predetermined region of wavelength.

Abstract: A diffractive optical element is composed of a plurality of diffraction gratings which differ in dispersion from each other and are laminated while being spaced to enhance diffraction efficiency for a particular order (design order) throughout an entire usable wavelength region, wherein edges of at least part of corresponding grating portions of the plurality of diffraction gratings are shifted from each other in a direction of arrangement of grating portions of each diffraction grating.

Abstract: A diffractive optical element includes a blazed diffraction grating having inclined facets and vertical facets arrayed in an alternating sequence, in which only the vertical facets of the blazed diffraction grating are frosted by ashing. Another diffractive optical element includes a blazed diffraction grating having inclined facets and vertical facets arrayed in an alternating sequence, in which only the vertical facets of the blazed diffraction grating have an opaque film formed thereon.

Abstract: A multibeam optical system that employs a multiline laser source emitting a laser beam at predetermined wavelengths, such as, for example, at wavelengths 488.0 nm and 514.5 nm, and a diffractive beam-dividing element having diffractive grating to divide the incident beam into nine diffracted beams. A design wavelength &lgr;M of the diffraction grating, at which the light quantity of the incident beam is equally distributed among the plurality of diffracted beams, is determined so as to satisfy the condition 488.0 nm<&lgr;M<514.5 nm. When the design wavelength &lgr;M is 501.1 nm, the light quantities of the divided beams, which are the sums of the quantities of the peak wavelengths 488. 0 nm and 514.5 nm, become nearly equal to one another among the nine diffraction orders. As a result, the distribution of the light quantities among the diffracted beams are balanced.

Abstract: An optical system has an optical functional surface including a common region used for conducting information recording and/or reproducing for both of a first optical information recording medium and a second optical information recording medium. The common region comprises a refractive surface of an imaginary basic aspherical surface and a optical path difference providing structure in which plural ring-shapes zones are separated around the center of an optical axis and neighboring ring-shaped zones are displaced to each other in a direction of an optical axis so as to cause an optical path difference obtained by multiplying a predetermined wavelength &lgr;s (&lgr;1<&lgr;s<&lgr;2) with almost an integer. The refractive surface of the imaginary basic aspherical surface is structured such that a spherical aberration becomes under on the first information recording medium and a spherical aberration becomes over on the second information recording medium.

Abstract: In accordance with the invention, an optical router for an optical communications system comprises a pair of transmissive Echelle gratings having their grating surfaces coupled by a waveguide grating. The arrangement provides for substantial design freedom in that the dispersive parameters include the shapes of the first and second Echelle gratings as well as the path length difference among the waveguides. Moreover the device eliminates any need for reflective surfaces in the Echelle gratings.

Abstract: An optical system includes a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis. A sign of the curvature of the lens surface having the diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in the optical system, a surface disposed nearest to an object side to a surface disposed immediately before the lens surface having the diffraction grating provided thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having the diffraction grating provided thereon. Further, an apex of an imaginary cone formed by extending-a non-effective surface of the diffraction grating is located adjacent to the center of curvature of the lens surface having the diffraction grating provided thereon.

Abstract: An overcoat protected diffraction grating. A replica grating having a thin aluminum reflective grating surface is produced by replication of a master grating or a submaster grating. The thin aluminum reflective surface may be cracked or have relatively thick grain boundaries containing oxides and hydroxides of aluminum and typically is also naturally coated with an aluminum oxide film. The grating is subsequently recoated in a vacuum chamber with a thin, pure, dense aluminum overcoat and then also in the vacuum the aluminum overcoat is coated with a thin film of MgF2. The grating is especially suited for use for wavelength selection in an ArF laser operating producing an ultraviolet laser beam at a wavelength of about 193 nm. The oxygen free aluminum overcoat prevents the ultraviolet light from causing damage by stimulating chemical reactions in grating materials under the aluminum grating surface or in the aluminum oxide film. The MgF2 additionally prevents oxidation on the surface, of the aluminum overcoat.