Abstract: A diffraction grating comprises a substrate (with index nsub) with a surface facing an optical medium (with index nmed<nsub), a dielectric or semiconductor layer of thickness t on the substrate surface (with index nL?nsub), and a set of diffractive elements on the layer (with index nR?nmed). The diffractive elements comprise a set of ridges protruding into the optical medium, which fills trenches between the ridges, and are characterized by a spacing ?, a width d, and a height h. Over an operational wavelength range, ?/2nsub<?<?/(nsub+nmed). An optical signal incident on the diffractive elements from within the substrate at an incidence angle exceeding the critical angle, nsub, nmed, nL, nR, ?, d, h, and t result in wavelength-dependent, first-order diffraction efficiency of the grating greater than a prescribed level over the operational wavelength range for both s- and p-polarized optical signals.

Abstract: An optical grating comprising a grating layer and two surface layers, the layers being arranged with the grating layer between the surface layers. The grating layer comprises a set of multiple, discrete, elongated first grating regions that comprise a first dielectric material and are arranged with intervening elongated second grating regions. The bulk refractive index of the dielectric material of the first grating regions is larger than the bulk refractive index of the second grating regions. The first surface layer comprises a first impedance matching layer, and the second surface layer comprises either (i) a second impedance matching layer or (ii) a reflective layer. Each said impedance matching layer is arranged to reduce reflection of an optical signal transmitted through the corresponding surface of the grating layer, relative to reflection of the optical signal in the absence of said impedance matching layer.

Abstract: Transmissive diffraction grating(s), reflector(s), and multiple optical sources/receivers are arranged such that each one of multiple optical signals at corresponding different wavelengths co-propagating along a multiplexed beam path would: (i) be transmissively, dispersively diffracted at a multiplexed transmission region of a grating; (ii) propagate between the multiplexed transmission region and multiple demultiplexed transmission regions of a grating undergoing reflection(s) from the reflector(s); (iii) be transmissively, dispersively diffracted at the demultiplexed transmission regions; and (iv) propagate between the demultiplexed transmission regions and the sources/receivers along multiple demultiplexed beam paths.

Abstract: A first transmissive diffraction grating includes a multiplexed transmission region; a second diffraction grating includes multiple demultiplexed transmission regions that are spatially displaced from one another and characterized by average corresponding grating-normal vector direction, grating wavevector magnitude, and grating wavevector direction. The demultiplexed transmission regions differ with respect to at least one of those parameters.

Abstract: An article comprising (i) a substantially flat substrate bearing a set of diffraction gratings, and (ii) a jewelry mounting secured to the substrate. The gratings occupy areas that correspond to a two-dimensional projection of a three-dimensional faceted gemstone. Sub-gratings are sized and positioned so that perceived sub-gratings images overlap. Sub-gratings within each set differs from adjacent sub-gratings with respect to grating wavevector magnitude, so that the overlapped perceived images result in an overall perceived color of sub-grating set. In one embodiment, two or more gratings comprise sub-grating sets having parallel wavevectors; each sub-grating set differs from at least one other with respect to grating wavevector direction. In another embodiment, one or more gratings comprise sub-grating sets having non-parallel wavevectors.

Abstract: An optical grating comprising a grating layer and two surface layers, the layers being arranged with the grating layer between the surface layers. The grating layer comprises a set of multiple, discrete, elongated first grating regions that comprise a first dielectric material and are arranged with intervening elongated second grating regions. The bulk refractive index of the dielectric material of the first grating regions is larger than the bulk refractive index of the second grating regions. The first surface layer comprises a first impedance matching layer, and the second surface layer comprises either (i) a second impedance matching layer or (ii) a reflective layer. Each said impedance matching layer is arranged to reduce reflection of an optical signal transmitted through the corresponding surface of the grating layer, relative to reflection of the optical signal in the absence of said impedance matching layer.

Abstract: A first article has a surface bearing a diffraction grating that comprises a plurality of elevated regions and recessed regions and a reflective coating that provides reflective diffraction within the article but is sufficiently thick to prevent diffraction outside the article. Alternatively, the reflective coating can be arranged to also provide reflective diffraction outside the article. A second article has a surface bearing a diffraction grating that comprises a plurality of elevated regions and recessed regions. Either (i) at least a portion of each ridge, or (ii) at least portion of each trench, comprises a material differing with respect to its refractive index or with respect to its optical transmissivity.

Abstract: A diffraction grating comprises a substrate with a set of protruding ridges and intervening trenches characterized by a ridge spacing ?, width d, and height h. The substrate comprises a dielectric or semiconductor material with a refractive index n1; the first substrate surface faces an optical medium with a refractive index n2 that is less than n1. Each ridge has a metal layer on its top surface of thickness t; at least a portion of the bottom surface of each trench is substantially free of metal. Over an operational wavelength range, ?/2n1<?<?/(n1+n2) can be satisfied. An optical signal can be incident on the diffractive elements from within the substrate at an incidence angle that exceeds the critical angle. The parameters n1, n2, ?, d, h, and t can be selected to yield desired polarization dependence or independence of the diffraction efficiency.

Abstract: A flat substrate bears a set of flat, coplanar diffraction gratings; a jewelry mounting is secured to the substrate. The gratings are arranged to occupy corresponding areas of the substrate that are arranged to correspond to a two-dimensional projection of multiple, non-coplanar facets of a three-dimensional gemstone. Each grating differs from one or more other gratings with respect to grating wavevector direction so that each grating differs from at least one other grating with respect to direction of dispersion of spectrally dispersed output directions of a diffracted portion of light incident on the gratings along a given input direction. The grating wavevectors are spatially distributed among the corresponding gratings to form two or more subsets of three or more gratings along which subsets the corresponding grating wavevector direction of each grating of the subset varies monotonically with position of that grating along a given dimension of the substrate.

Abstract: An optical grating comprising a grating layer and two surface layers, the layers being arranged with the grating layer between the surface layers. The grating layer comprises a set of multiple, discrete, elongated first grating regions that comprise a first dielectric material and are arranged with intervening elongated second grating regions. The bulk refractive index of the dielectric material of the first grating regions is larger than the bulk refractive index of the second grating regions. The first surface layer comprises a first impedance matching layer, and the second surface layer comprises either (i) a second impedance matching layer or (ii) a reflective layer. Each said impedance matching layer is arranged to reduce reflection of an optical signal transmitted through the corresponding surface of the grating layer, relative to reflection of the optical signal in the absence of said impedance matching layer.

Abstract: An optical grating comprising a grating layer and two surface layers, the layers being arranged with the grating layer between the surface layers. The grating layer comprises a set of multiple, discrete, elongated first grating regions that comprise a first dielectric material and are arranged with intervening elongated second grating regions. The bulk refractive index of the dielectric material of the first grating regions is larger than the bulk refractive index of the second grating regions. The first surface layer comprises a first impedance matching layer, and the second surface layer comprises either (i) a second impedance matching layer or (ii) a reflective layer. Each said impedance matching layer is arranged to reduce reflection of an optical signal transmitted through the corresponding surface of the grating layer, relative to reflection of the optical signal in the absence of said impedance matching layer.

Abstract: A first article has a surface bearing a diffraction grating that comprises a plurality of elevated regions and recessed regions and a reflective coating that provides reflective diffraction within the article but is sufficiently thick to prevent diffraction outside the article. Alternatively, the reflective coating can be arranged to also provide reflective diffraction outside the article. A second article has a surface bearing a diffraction grating that comprises a plurality of elevated regions and recessed regions. Either (i) at least a portion of each ridge, or (ii) at least portion of each trench, comprises a material differing with respect to its refractive index or with respect to its optical transmissivity.

Abstract: A packaging article comprises first and second packaging members with one or more depressions and corresponding protrusions, respectively, and can be assembled with their each protrusion received within the corresponding depression. A transverse cross section of each depression is concave. A transverse cross section of each protrusion includes a secondary protrusion that forms a longitudinal ridge; a longitudinal cross section of the ridge comprises one or more concavities. A substantially rectangular object is place in a depression and the first and second packaging members are assembled. The object, received within the depression and located between the assembled packaging members, rests with two opposing edges of the object urged against the concave surface of the depression with corresponding lines of contact oriented substantially longitudinally, and with two other opposing edges of the object urged against the concavity.

Abstract: An article comprises a volume of material having at least one faceted or curved surface, and at least one diffraction grating on at least one surface of the article. The diffraction grating comprises a set of diffractive elements formed in a deformable layer attached to the surface of the article. A method comprises forming the set of diffractive elements by deformation of the deformable layer, and attaching the deformable layer to a surface of the article. The layer can be deformed to form the diffractive elements before or after it is attached to the surface of the article.

Abstract: A spectral filter comprises a planar optical waveguide having at least one set of diffractive elements. The waveguide confines in one transverse dimension an optical signal propagating in two other dimensions therein. The waveguide supports multiple transverse modes. Each diffractive element set routes, between input and output ports, a diffracted portion of the optical signal propagating in the planar waveguide and diffracted by the diffractive elements. The diffracted portion of the optical signal reaches the output port as a superposition of multiple transverse modes. A multimode optical source may launch the optical signal into the planar waveguide, through the corresponding input optical port, as a superposition of multiple transverse modes. A multimode output waveguide may receive, through the output port, the diffracted portion of the optical signal. Multiple diffractive element sets may route corresponding diffracted portions of optical signal between one or more corresponding input and output ports.

Abstract: An optical apparatus comprises at least one primary diffraction grating and at least one reference diffraction grating each formed on or within a common grating substrate. The reference diffraction grating is arranged so as to diffract and disperse spatially according to wavelength a reference optical signal incident on the reference diffraction grating at an input incidence angle. The primary diffraction grating is arranged so as to diffract and disperse spatially according to wavelength an input optical signal incident on the primary diffraction grating at the input incidence angle. The reference and primary diffraction gratings exhibit at least one differing grating structural parameter. The reference and primary diffraction gratings are arranged so that a diffracted and spatially dispersed reference optical signal having at least one known wavelength component defines at least one spatial wavelength calibration reference for the diffracted and spatially dispersed input optical signal.

Abstract: An optical grating comprising a grating layer and two surface layers, the layers being arranged with the grating layer between the surface layers. The grating layer comprises a set of multiple, discrete, elongated first grating regions that comprise a first dielectric material and are arranged with intervening elongated second grating regions. The bulk refractive index of the dielectric material of the first grating regions is larger than the bulk refractive index of the second grating regions. The first surface layer comprises a first impedance matching layer, and the second surface layer comprises either (i) a second impedance matching layer or (ii) a reflective layer. Each said impedance matching layer is arranged to reduce reflection of an optical signal transmitted through the corresponding surface of the grating layer, relative to reflection of the optical signal in the absence of said impedance matching layer.

Abstract: A method comprises computing an interference pattern between a simulated design input optical signal and a simulated design output optical signal, and computationally deriving an arrangement of at least one diffractive element set from the computed interference pattern. The interference pattern is computed in a transmission grating region, with the input and output optical signals each propagating through the transmission grating region as substantially unconfined optical beams. The arrangement of diffractive element set is computationally derived so that when the diffractive element set thus arranged is formed in or on a transmission grating, each diffractive element set would route, between corresponding input and output optical ports, a corresponding diffracted portion of an input optical signal incident on and transmitted by the transmission grating. The method can further comprise forming the set of diffractive elements in or on the transmission grating according to the derived arrangement.

Abstract: A reconfigurable add-drop multiplexer (R-OADM) comprises an array of channel waveguides coupling two groups of diffractive element sets on a slab waveguide. The channel waveguides include switchable reflectors or are coupled to other channel waveguides by optical switches. Switching a reflector to reflect or setting a switch to couple two waveguides results in a corresponding wavelength channel being added or dropped. Switching the reflector to transmit or setting the switch to uncouple the two waveguides allows the corresponding wavelength channel to pass through the R-OADM without being added or dropped.

Abstract: An optical multiplexing device includes an optical element having at least one set of diffractive elements, and an optical reflector. The reflector routes, between first and second optical ports, that portion of an optical signal transmitted by the diffractive element set. The diffractive element set routes, between first and multiplexing optical ports, a portion of the optical signal that is diffracted by the diffractive element set. More complex optical multiplexing functionality(ies) may be achieved using additional sets of diffractive elements, in a common optical element (and possibly overlaid) or in separate optical elements with multiple reflectors. Separate multiplexing devices may be assembled with coupled ports for forming more complex devices. The respective portions of an optical signal transmitted by and reflected/diffracted from the diffractive element set typically differ spectrally.