Abstract: Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs and Bragg gratings, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated Bragg gratings (EBGs). EBGs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) grating. Removing the liquid crystal from the cured grating provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

Abstract: Systems and methods related to a memory system with a predictable read latency from media with a long write latency are described. An example memory system includes an array of tiles configured to store data corresponding to a cache line associated with a host. The memory system further includes control logic configured to, in response to a write command from a host, initiate writing of a first cache line to a first tile in a first row of the tiles, a second cache line to a second tile in a second row of the tiles, a third cache line to a third tile in a third row of the tiles, and a fourth cache line in a fourth row of the tiles. The control logic is configured to, in response to a read command from the host, initiate reading of data stored in an entire row of tiles.

Abstract: Many embodiments in accordance with the invention are directed towards waveguides implementing birefringence control. In some embodiments, the waveguide includes a birefringent grating layer and a birefringence control layer. In further embodiments, the birefringence control layer is compact and efficient. Such structures can be utilized for various applications, including but not limited to: compensating for polarization related losses in holographic waveguides; providing three-dimensional LC director alignment in waveguides based on Bragg gratings; and spatially varying angular/spectral bandwidth for homogenizing the output from a waveguide. In some embodiments, a polarization-maintaining, wide-angle, and high-reflection waveguide cladding with polarization compensation is implemented for grating birefringence. In several embodiments, a thin polarization control layer is implemented for providing either quarter wave or half wave retardation.

Abstract: One embodiment provides an apparatus for displaying an image comprising: a first optical substrate comprising at least one waveguide layer configured to propagate light in a first direction, wherein the at least one waveguide layer of the first optical substrate comprises at least one grating lamina configured to extract the light from the first substrate along the first direction; and a second optical substrate comprising at least one waveguide layer configured to propagate the light in a second direction, wherein the at least one waveguide layer of the second optical substrate comprises at least one grating lamina configured to extract light from the second substrate along the second direction; wherein the at least one grating lamina of at least one of the first and second optical substrates comprises an SBG in a passive mode.

Abstract: A yield model generates a yield map for an agricultural field. A measurement system generates measured indicators that are a measurement or quantification of crop yield in the agricultural field. An observation system generates observed indicators that are spatial agricultural datasets describing observed characteristics of the agricultural field. To generate the yield map, the yield model generates a field array representing the agricultural field. The yield model generates an input array and a yield array by mapping the observed indicators and measured indicators to cells of the field array, respectively. The yield model determines a yield value for each cell of the yield array not including a mapped indicator using information included in the corresponding cells of the input array. The yield model generates a yield map using the determined yield values and the yield values in the yield array.

Abstract: A waveguide apparatus comprises in combination: a light pipe with an optical axis for guiding light therethrough; a light coupling element in optical contact with an elongate portion of the reflecting surface of the light guide; and an optical waveguide in optical contact with the coupling element.

Abstract: Systems and methods related to ensuring the integrity of data stored in a memory by using a watermark are described. An example method in a system including a processor and a memory may include receiving data for storage at an address in the memory. The method may further include after encoding the data with an error correction code to generate intermediate data having a first number of bits, reversibly altering the intermediate data with a watermark to generate watermarked data for storage in the memory, where the watermark is generated by applying a cryptographic function to a user key and the address, and where the watermarked data has a second number of bits equal to the first number of bits.

Abstract: There is provided an illumination device comprising: a laser; a waveguide comprising at least first and second transparent lamina; a first grating device for coupling light from the laser into a TIR path in the waveguide; a second grating device for coupling light from the TIR path out of the waveguide; and a third grating device for applying a variation of at least one of beam deflection, phase retardation or polarization rotation across the wavefronts of the TIR light. The first second and third grating devices are each sandwiched by transparent lamina.

Abstract: A near eye optical display includes a waveguide comprising a first surface and a second surface, an input coupler, a fold grating, and an output grating. The input coupler is configured to receive collimated light from a display source and to cause the light to travel within the waveguide via total internal reflection between the first surface and the second surface to the fold grating; the fold grating is configured to provide pupil expansion in a first direction and to direct the light to the output grating via total internal reflection between the first surface and the second surface; and the output grating is configured to provide pupil expansion in a second direction different than the first direction and to cause the light to exit the waveguide from the first surface or the second surface.

Abstract: Multiplexed reflection and transmission gratings, and methods of their manufacture, are provided that improve uniformity with laser light, that is, reduced banding and other illumination artifacts occurring in waveguides. The mechanism for this can be the multiple reflections between the waveguide reflecting surfaces and the reflection hologram, which promote illumination averaging as beam propagation processes within a waveguide. In some gratings, a beam splitter layer overlapping the multiplexed gratings can be provided for the purposes of reducing banding in a laser-illuminated waveguide. The beam splitter can be provided by one or more dielectric layers. The beamsplitter can have sensitivity to one polarization. The beamsplitter can be sensitive to S-polarization. The beam splitter can be an anti-reflection coating optimized for normal incidence that becomes reflective at high TIR angles when immersed in glass or plastic.

Abstract: An optical display comprises: a first waveguide comprising a first surface and a second surface, an input coupler, a fold grating, and an output grating. The input coupler receives collimated first wavelength light from an Input Image Node causes the light to travel within the first waveguide via total internal reflection between the first surface and the second surface to the fold grating. The fold grating provides pupil expansion in a first direction directs the light to the output grating via total internal reflection between the first surface and the second surface. The output grating provides pupil expansion in a second direction different than the first direction and causes the light to exit the first waveguide from the first surface or the second surface. At least one of the input coupler, fold grating and output grating is a rolled k-vector grating, and the fold grating is a dual interaction grating.

Abstract: Systems and methods related to a memory system with a predictable read latency from media with a long write latency are described. An example memory system includes an array of tiles configured to store data corresponding to a cache line associated with a host. The memory system further includes control logic configured to, in response to a write command from a host, initiate writing of a first cache line to a first tile in a first row of the tiles, a second cache line to a second tile in a second row of the tiles, a third cache line to a third tile in a third row of the tiles, and a fourth cache line in a fourth row of the tiles. The control logic is configured to, in response to a read command from the host, initiate reading of data stored in an entire row of tiles.

Abstract: Provided are therapeutic compositions containing microbial populations for prevention, treatment and reduction of symptoms associated with a dysbiosis of a mammalian subject such as a human.

Abstract: A memory device comprises a memory array, a counter unit, and a service unit. The memory array comprises cells arranged in rows and columns, wherein a subset of the cells in each of the rows holds a row activation count for each row. The counter unit, in response to an activation of the row caused by a read operation on at least a portion of the row, increments the row activation count for at least one of the rows prior to a completion of the read operation, and writes-back the row activation count in an incremented state to the subset of the cells in the row that held the row activation count prior to the activation. The service unit is coupled to the counter unit and performs a service with respect to one or more other rows, offset from the row, in response to the row activation count associated with the row satisfying service criteria.

Abstract: An eye tracker comprises a light source; a detector; and first and second waveguides. The first waveguide comprises an input coupler for coupling source light into a waveguide path and a first grating for coupling light out of the waveguide path onto an eye. The second waveguide comprises a second grating for coupling light reflected from the eye into a waveguide path and an output coupler for coupling light out of the waveguide path onto the detector. The second grating is optically configured for imaging the eye onto the detector.

Abstract: A method for producing holograms with a multiplicity of holographic prescriptions from a single master is provided. A multiplicity of holographic substrates each containing a first hologram is stacked on a second holographic recording medium substrate. The first hologram is designed to diffract light from a first direction into a second direction. When expose to illumination from the first direction zero order and diffracted light from each first hologram interfere in the second holographic recording medium substrate forming a second hologram. The second hologram is then copied into a third holographic recording medium substrate to provide the final copy hologram.

Abstract: There is provided an object tracker comprising: a first waveguide; a source of illumination light; a detector optically coupled to said waveguide; and at least one grating lamina formed within said waveguide. Illumination light propagating along a first optical path from said source to an object in relative motion to the object tracker. Image light reflected from at least one surface of an object is deflected by said grating lamina into a second optical path towards said detector.

Abstract: Disclosed herein is a switchable Raman Nath grating configured to be implemented in a waveguide-based display. The waveguide-based display may include: a waveguide; a light source; a coupler for directing light from the light source into a total internal reflection path within the waveguide; a switchable Raman-Nath grating supported by said waveguide operative to provide a first polarization direction sensitivity under a first voltage and a second polarization direction sensitivity under a second voltage; a voltage generator for applying a first voltage or a second voltage across the switchable Raman-Nath grating, where the switchable Raman-Nath grating receives light in the total internal reflection path. Switchable Raman-Nath gratings may provide advantageous effects which may make them particularly suitable for despeckler gratings.

Abstract: A device includes an analog current division circuit configured to divide an input current into a first current and a second current, and a multiplexer array including a plurality of switches to provide the first current to a first of three colors of LEDs and the second current to a second of three colors of LEDs simultaneously during a first portion of a period, the first current to the second of three colors of LEDs and the second current to a third of three colors of LEDs simultaneously during a second portion of the period, and the first current to the first of three colors of LEDs and the second current to the third of three colors of LEDs simultaneously during a third portion of the period.

Abstract: Systems and methods for providing holographic waveguide display using integrated gratings in accordance with various embodiments of the invention are illustrated. One embodiment includes a waveguide display including a source of light, and a first waveguide including a grating structure including first and second gratings, and an input coupler configured to couple a first field-of-view portion of light, and couple a second field-of-view portion of light, wherein the first grating is configured to provide beam expansion in a first direction for the first field-of-view portion of light, and provide beam expansion in the first direction and beam extraction towards a viewer for the second field-of-view portion of light, the second grating is configured to provide beam expansion in a second direction for the second field-of-view portion of light, and provide beam expansion in the second direction and beam extraction towards a viewer for the first field-of-view portion of light.