Abstract:
A diffraction grating light valve modulates an incident beam of light. A plurality of elongated elements each have a reflective surface. The elongated elements are suspended with their respective ends substantially coplanar. Alternate ones of the elongated elements are electrically coupled for receiving a first bias voltage. The interdigitated elongated elements are electrically coupled for receiving a second bias voltage. By applying an appropriate first and second biasing voltages, all the reflective surfaces can be maintained in a first plane. When all the elongated elements are in the first plane, the diffraction grating light valve reflects the beam of light. A predetermined group of the elongated elements, preferably alternate ones, are deformable to be substantially coplanar in a second plane which is parallel to the first plane. When the predetermined group of elements is in the second plane, the diffraction grating light valve diffracts the beam of light.
Abstract:
A diffraction surface (100) and a method of making the surface. The surface (100) may be applied to labels and other items, to identify the origin of the goods to which the label is attached. The surface (100) can include a block grating. For example, the surface could include a plurality of blocks (350) which adapted when illuminated will produce a recognisable image on an intercepting surface. The diffraction grating is manufactured by processing a data stream indicative of the image. Processing of the data stream includes obtaining a Fourier Transform of the data stream. Preferably, the data stream is clipped and quantised.
Abstract:
A multi-line continuous wideband tunable laser (1) utilizes a symmetric or asymmetric grating (5) and a plurality of optical fibers (3), each of which forms a part of a respective laser cavity optical axis. By simultaneously altering both the periodicity of the intersections of the grating (5) with the plurality of optical axes established by the plurality of optical fibers (3) and the effective cavity length of each laser (1), a single-line spectral output is achieved at any desired point in the operating band.
Abstract:
A hybrid refractive and diffractive achromatic lens (10, 20, 30) suited for single-use or inexpensive single-lens cameras (100) operating in visible spectral range. The lens comprises a body of optically transmissive material having an index of refraction at a wavelength approximately at the center of said range of at least 1.45. The lens body having a first and second surface (1, 2) on opposite sides thereof, at least one of said surfaces (1, 1', 1"; 2, 2', 2") being curved to provide a refractive portion having power and introduces chromatic aberration, the lens (10, 20, 30) having a diffractive portion (3, 3', 3") having power which reduces the chromatic aberration introduced by the refractive portions.
Abstract:
A method of manufacturing a diffractive surface comprising: rotating a surface to be cut at a rate W > 1,500 RPM; translating a cutting tip T at low speed V where V
Abstract:
A diffractive device has a surface relief structure which, when illuminated by a light source, generates at least two diffraction images which can be observed from particular ranges of viewing angles around the device. At least one surface region (3) has two or more superimposed diffractive surface structures (1, 2), each of which gives rise to a separate diffraction image or component of a diffraction image. The diffractive device is particularly suitable as anti-forgery security device on banknotes, credit cards, cheques, share certificates and other similar documents.
Abstract:
A diffraction grating assembly is constructed from a silicon substrate (2). The diffraction grating assembly comprises a support member (1a) formed in a cavity (4) etched in the substrate (2). A diffraction grating (1) is formed on the support member (1a), and means (3) are provided for supporting the support member on the substrate (2) for pivotal movement. Means (5a, 5b) are also provided for controlling the pivotal movement of the support member (1a).
Abstract:
This invention relates to a kind of novel building decorative materials. A model disk or a mold of press rollers is duplicated by use of a dry plate produced by laser holography or etch-graving by diffraction grating of rays of light and then is pressed onto a base material (1) such as transparent glass, hard glass or a propylenic acid film to form a laser hologram or diffraction grating pattern. A highly corrosion-resistant metallic reflection film (2) is applied thereon by plating and a protective film (3) is further deposited thereon. In a state where rays of light exist, a physical diffraction phenomenon takes place and the rays of light are reflected by the metallic reflection film, thereby exhibiting bright metallic luster in rich gradation of seven colors or a cubic hologram pattern. The colors change according to viewing angles, so that various patterns or designs can be combined. Besides being provided with the optical properties of peculiar physical diffraction, the hologram mosaic of the present invention is free from distinct change in its decorative effect even when used for an extended period of time so that it can be used widely as permanent building decorations on interior or exterior walls.
Abstract:
An interferometer which comprises: (1) a single, coherent light source; (2) a first converging lens positioned on the optical axis of said coherent light source; (3) a beam-splitting arrangement positioned on said optical axis and spaced from said first converging lens by a distance greater than the focal length of said lens; (4) a second converging lens positioned on said optical axis to receive and to focus the two beams emanating in use from the beam-splitting arrangement; and (5) a mirror arrangement positioned so that the beams focussed by said second converging lens impinge on the mirror system and so that the reflected beams are brought to intersect at a focal point and with a large angle between the principal rays of the two beams.