Abstract: A first binary diffractive optical element has a multi-level surface relief phase grating structure on a substrate. The first binary diffractive optical element can be divided into regions commensurate with resolution requirements of the intended optical application and the diffraction efficiency of each region of the binary diffractive optical element measured. The lowest measured diffraction efficiency for a region of the first binary diffractive optical element will be taken as the reference efficiency. The diffraction efficiencies for all the regions of the binary diffractive optical element will be reduced region by region to the common value of the lowest measured diffraction efficiency by introducing compensating diffractive losses to the regions by a second, corrector binary diffractive optical element which has a binary surface relief phase grating structure on a substrate.

Abstract: A first binary diffractive optical element has a multi-level surface relief phase grating structure on a substrate. The first binary diffractive optical element can be divided into regions commensurate with resolution requirements of the intended optical application and the diffraction efficiency of each region of the binary diffractive optical element measured. The lowest measured diffraction efficiency for a region of the first binary diffractive optical element will be taken as the reference efficiency. The diffraction efficiencies for all the regions of the binary diffractive optical element will be reduced region by region to the common value of the lowest measured diffraction efficiency by introducing compensating diffractive losses to the regions by a second, corrector binary diffractive optical element which has a binary surface relief phase grating structure on a substrate.

Abstract: According to the present invention, a diffraction element comprising a transparent substrate having a first face and a second face; periodic grooves engraved on the first face; a reflective film provided on the first face having the periodic grooves; and a antireflection film provided on the second face, wherein the periodic grooves and the reflective film constitute a diffraction grating.

Abstract: A diffraction grating unit includes a reflection type diffraction grating; a transparent medium; and a filter which is formed on the diffraction grating through the transparent medium so as to be disposed on an incident surface of the diffraction grating unit; wherein the filter transmits therethrough a ray having a specific wavelength but reflects a further ray having a wavelength equal to a half of the specific wavelength of the ray, and a second-harmonic generator employing the diffraction grating unit.

Abstract: Optical reproducing apparatus utilizes a dual diffraction grating having first and second diffraction gratings with the diffraction gratings oriented at an angle with respect to one another to polarize an incident return beam into TM and TE components. TM and TE components emerge from the dual diffraction grating at a slight angle with respect to one another and are focused on a photodetector chip by an objective lens. In accordance with a first specific embodiment of the apparatus, the TM and TE polarized components are focused directly on a photoelectric chip, with the TE component focused on a spot size focus detector comprised of three rectangular photoelectric elements. One photoelectric element is disposed between the other two with a pair of parallel interfaces. Disturbances introduced into the TE beam are in the direction of the parallel interfaces, rendering the spot size focus detector wavelength-insensitive.

Abstract: A reflecting diffraction grating is formed by depositing a metal in vacuum on a blazed diffraction grating having a cross section of regular projections and recesses to provide a metal reflecting film, and forming an SiO protective film on the reflecting film by vacuum deposition.

Abstract: A rigid three dimensional diffraction grating is provided in the form of an ABA block copolymer that forms domains. The A domain of the block copolymer is preferably polystyrene and the B domain of the copolymer is preferably a diene such as polybutadiene or polyisoprene. The molecular weight of the diene can be synthetically controlled to regulate the interelement spacing of the polystyrene domains and control the diffraction obtained from the grating.

Abstract: A two-metal grating is produced by vacuum depositing a first dielectric cing upon a separation layer formed upon a mandrel; then depositing a first optically opaque metallic layer, etching the layer to form stripes; then vacuum depositing a second optically opaque film; then electroforming a backing structure and separating the dielectric coating from the separation layer on the mandrel to form a free-standing grating structure having a smooth surface. This structure can then be affixed to a metallic mirror. A buried phase grating can also be fabricated by additionally depositing a second dielectric layer and a third metallic layer.

Abstract: The present invention involves a corrective optical lens construction and process for its manufacture. The lens construction consists of a glass lens having a corrective layer consisting of a blazed grating of annuli whose angles are formed to correct aberrations in the glass lens. In a first embodiment, the corrective layer is formed on one convex surface of the lens. In a second embodiment, the corrective layer is formed on a second convex surface of the lens. Embodiments also describe alternative lens shapes and corrective layer construction. A method of manufacturing the lens is also disclosed in which the resin corrective layer is molded to the glass lens.

Abstract: An optical device for receiving incident light having a minimum wavelength, and for producing a resultant light containing an optical image. The device includes a first material having a first index of refraction and a surface embossed with an optical interference pattern, and a second material having a second index of refraction deposited onto the embossed surface of the first material. The depth of deposition is at least equal to three quarters of the minimum wavelength component of the incident light within the second material.

Abstract: A phase grating optical low-pass filter having wavelength selectivity consisting of a plurality of layers which are the same in refractive index at a certain wavelength and different from one another in refractive index dispersion, and has a configuration for generating a phase difference at a boundary of the layers.

Abstract: A dual diffraction grating useful in optical disk heads comprises first and second light diffracting surfaces of identical pitch and depth, wherein the diffraction grooves of the first and second diffraction surfaces are angularly oriented with respect to one another. Incident light beams are diffracted into first and second components with the first components being TM polarized components and the second components being TE polarized components. Upon emerging from the dual diffraction grating, the first and second components diverge with respect to one another because the first component is substantially transmitted through the diffraction grating without diffraction while the second component is diffracted. The initial diffraction by the first grating causes the TE component to diverge away from the TM component while the second diffraction grating diffracts the TE component back toward the TM component so as to diverge therefrom by only a slight angle of, for example, about 0.1.degree. to 3.0.degree..

Abstract: A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described.

Abstract: A polarizer and a method of manufacturing the polarizer comprising first zones which are formed by one or more layers and second zones which are formed by one or more layers, the zones being alternately and horizontally arranged on a common plane. A material of at least one layer of at least either zones is birefringent, and the birefringent layer is formed by oblique vapor deposition. The polarizer, excellently suited for quantity production and for space and size reduction, can be formed directly and simply on the planes of light beam incidence or emergence of various optical elements. The invention also concerns polarizer-equipped optical elements and a method of manufacturing such elements which have the polarizer directly formed by oblique deposition on the plane of light beam incidence, emergence, or reflection of the optical elements.

Abstract: A wavelength-selective phase-grating optical low-pass filter has a phase difference structure formed at a boundary face between two layer materials which have different refractive index distributions and an identical refractive index at an intended wavelength. A trapezoid form is adopted at the phase difference section of the phase grating to achieve an excellent MTF characteristic in the condition of: ##EQU1## thereby obtaining a wavelength-selective phase-grating optical low-pass filter capable of adjusting the cutoff characteristic and improving the characteristic in the low-frequency region of the spatial frequency.

Abstract: An optical modulator includes a substrate, a first waveguide layer formed on the substrate, a second waveguide layer stacked together with the first waveguide layer in a direction of a thickness thereof on the substrate, the second waveguide layer having a waveguide mode different from that of the first waveguide layer, a diffraction grating formed in a region where the waveguide modes of the first and second waveguide layers overlap each other, and an electrode. When the electrical signal is applied through the electrode, the wavelength of the light coupled by the diffraction grating is changed, and light output from the second waveguide layer is modulated in accordance with the electrical signal. A method of modulating light using the above optical modulator is also disclosed.

Abstract: A hybrid filter having an inherently planar interference stack adhered to a nonplanar diffractive grating. The filter can have a planarization layer between the stack and grating. The hybrid filter has a spectral light transmittance value that is at least equal to or greater than the transmittance value of the least transmissive filter component. The filter also has a spectral bandwidth that is narrower than the spectral bandwidth of either filter component.