Abstract: The invention provides a tunable filter that can minimize adjacent channel cross talk despite an increase of a number of available wavelengths and quickly switch a wavelength to be used, and manufacturing method thereof, and also an optical switching device comprising such tunable filter. In a tunable filter having a Fabry-Perot etalon structure, not less than two cavity gaps 114 to 116 are provided and separation between the cavity gaps is controlled by any of electrostatic drive, electromagnetic drive or piezoelectric drive. In this case, the cavity gaps can be formed through the steps of forming a sacrificial layer in advance where a cavity gap is to be formed; forming a plurality of optical multilayer films 100 to 103; and removing the sacrificial layer by etching. Substrates 107 and 109 are combined through a supporting column 108.

Abstract: A rotating periodic color-regulating module of the image display device is disclosed to improve the usage of light. The rotating periodic color-regulating module comprises a color separating light guide and a color-regulating processor. By using a grating element installed in front of the color separating light guide, the incident light is interleaved into three parts of different wavelengths, red (R), green (G) and blue (B), propagating toward the corresponding color filters. Part of the light is reflected by the color filters, then reflected by the mirror around the grating element, and goes back to the color filters. The incident light is divided into three uniform beams of light, R, G and B, to the color-regulating processor. The color-regulating processor changes the outgoing position and order of the light beams periodically and rapidly for displaying image.

Abstract: In a multilayered optical thin-film filter having multiple quarter wavelength thick optical thin films with different refractive indices, the filter includes a plurality of unit cavities that are stacked multiple times via a connection layer, each unit cavity including a first reflector layer, a spacer layer in contact with the first reflector layer, and a second reflector layer in contact with the spacer layer. The first reflector layer is a layered body and the second reflector layer is a layered body. The spacer layer is a multilayered optical thin film with a high refractive index obtained by layering even number of films, or is composed of a multilayered optical thin film with a low refractive index. The connection layer is a multilayered optical thin film with a low refractive index obtained by layering odd number of films.

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: Method of producing a member of a periodic structure having, alternately stacked, a plurality of high refractive index layers and a plurality of low refractive index layers. The method includes alternately superimposing on each other a plurality of first sheet glasses having a high refractive index and a plurality of second sheet glasses having a low refractive index, and heating the stacked member to at least a glass transition temperature. In addition, the method includes applying a pressure to the heated stacked member perpendicularly to a principal surface of the sheet glasses or extending the heated stacked member parallel to the principal surface of the sheet glasses, thereby integrating the stacked member while reducing the thickness of each of the sheet glasses.

Abstract: A wavelength characteristic control device capable of variably controlling a wavelength characteristic in a satisfactory manner. A polarized light wavelength characteristic changing element has a wavelength characteristic such that the transmittances or reflectances of P- and S-polarized rays vary differently with respect to wavelength. Polarization variable control means subjects the plane of polarization of the polarized light incident on the polarized light wavelength characteristic changing element to rotatory control to change the ratio of the P-polarized ray to the S-polarized ray, thereby variably controlling the wavelength characteristic.

Abstract: The present invention provides a multi-channel tunable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings imprinted into a filter material, such as Lithium Niobate. In another embodiment, the filter comprises a bank of gratings imprinted on a thin-film filter. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack. In another embodiment, the gratings are recorded by a phase masking method.

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: One-dimensional (1D) photonic crystal prisms can separate a beani of polychromatic electromagnetic waves into constituent wavelength components and can utilize unconventional refraction properties for wavelength dispersion over significant portions of an entire photonic band rather than just near the band edges outside the photonic band gaps. Using a 1D photonic crystal simplifies the design and fabrication process and allows the use of larger feature sizes. The prism geometry broadens the useful wavelength range, enables better optical transmission, and exhibits angular dependence on wavelength with reduced non-linearity. The properties of the 1D plhotonic crystal prism can be tuned by varying design parameters such as incidence angle, exit surface angle, and layer widths. The 1D photonic crystal prism can be fabricated in a planar process, and can be used as optical integrated circuit elements.

Abstract: Disclosed is an optical element comprising in order a light source, air, at least one thin layer having a thickness of 80 to 200 nm, and a thick layer, each layer varying in refractive index (RI) by at least 0.05 from the next adjacent layer, in an alternating manner.

Abstract: An eyepiece optical member introduces into an exit pupil an observation image formed by an observation image forming member. The eyepiece optical member is configured so that a first prism that has a first entrance surface, a reflecting surface and a first exit surface arranged with a first prism medium between and a second prism that has a second entrance surface and a second exit surface arranged with a second prism medium between are joined to each other via a hologram element interposed between the first exit surface and the second entrance surface. The reflecting surface is shaped as a concave surface to give a positive power for rays reflected therefrom. The first entrance surface and the second exit surface are shaped as curved surfaces, respectively, to give a power for rays transmitted therethrough.

Abstract: An optical system provides high-contrast operation by collecting zero order light. The optical system comprises a light modulator and a collector. The light modulator is preferably a grating light valve™ light modulator including a plurality of elements selectively operable in a first mode and a second mode, wherein a gap between adjacent elements is equal to or less than a wavelength of an incident light beam. The plurality of elements in the first mode reflect light along a return path, where the plurality of elements in the second mode direct light away from the return path. The collector is coupled to the light modulator to collect zero order light along the return path while the plurality of elements are in the first mode and to collect zero order light along the return path while the plurality of elements are in the second mode.

Abstract: The invention relates to a holographic display for storing and reducing a spatial structure, having a holographic screen forming the master hologram, and having a projection device which illuminates the holographic screen in order to reproduce the spatial structure. The invention, for the holographic display to be constructed from a plurality of holographic screens which are respectively assigned to a dedicated projection device.

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 amorphous diamond coating applied onto mirrored optics in an infrared motion sensor to block specific wavelengths of energy from a “white light” source like a halogen lamp, without reducing the reflectivity of the mirror surface in the Mid-Infrared wavelengths. A specific thickness of diamond-like-coating is applied on top of the reflective metal surface of a mirrored part, thereby reducing the mirror's reflectivity at visible and near-Infrared wavelengths known to be problematic for IR motion sensors, such as those emitted from halogen lamps. The coating has no significant detrimental effect on mid-Infrared reflectivity, so the IR motion sensor's performance is otherwise unaffected.

Abstract: A light transmission system includes a laser, an optical fiber, and a transfer lens. The transfer lens transfers light emitted by the laser into the optical fiber. The transfer lens includes a diffractive surface for receiving and collimating the light originating form the laser. The diffractive surface is defined by a surface function that includes a first phase function having angular symmetry and a second phase function having radial symmetry. The second phase function includes a cusp region with a discontinuous slope therein. The transfer lens provides reflection management so that light reflected from the end of the optical fiber is not focused at a location at which light is emitted by the laser and also favorable launch conditions so that light launched into the optical fiber avoids index anomalies along the axis of the optical fiber.

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: An observation optical system comprises an image display element and an eyepiece optical system which introduces an image formed by the image display element to a center of an eye of an observer without forming an intermediate image, so as to allow the observer to observe the image as a virtual image. The eyepiece optical system is constructed and arranged to bend the optical axis using reflecting surfaces so as to be compact. The image observation optical system can be made compact enough to be usable as an image display unit for a cellular phone or a portable intelligent terminal, and can achieve high image definition and wide field angle while controlling chromatic aberration of magnification to be small.

Abstract: There is disclosed a method for the holographic recording of data, wherein a hologram containing the date is recorded in a waveguide layer (3). The holograms are formed in a layer structure containing multiple waveguide layers (3). Coupling means (12) are provided for selectively coupling the reference beam (11) into the single waveguide layers (3) of the layer structure. The invention also relates to an arrangement for holographic recording of data, comprising a data storage medium with a waveguide holographic storage layer, and an optical system for writing and reading the holograms. The optical system comprises means for imaging an object beam (5) and a reference beam (11) on the storage medium. The arrangement comprises multiple waveguide holographic storage layers (3) in the storage medium, and means for selectively coupling the reference beam (11) into the single waveguide layers (3) of the layer structure.

Abstract: A display or image capture apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly and the scanning assembly simultaneously scans more than one of the beams. The light sources are positioned so each beam illuminates a discrete region of the image field that is substantially non-overlapping with the other regions. Each line of the image is formed from segments where two or more of the segments define a line of an image. Because the lines are made from discrete segments, the problem of raster pinch is reduced. The achievable resolution of the display for a given scan angle and mirror size is increased relative to a mirror sweeping a single beam. Segments of different wavelengths can be overlapped to produce a color display.