Abstract: An energy storage and retrieval system including an air chamber, a first air compressor operating with Heat Transfer Liquid (HTL-compressor) connected to the air chamber, a second turbine, operating with Heat Transfer Liquid (HTL-turbine) connected to the air chamber, accepting compressed air from the air chamber and producing work. Related apparatus and methods are also described.

Abstract: A method for converting heat to mechanical work includes providing incoming heat transfer liquid (HTL) at a first temperature to a plurality of mixing chambers, providing incoming compressed gas at a second temperature to the plurality of mixing chamber, enabling the gas and the HTL to mix, producing a gas-and-HTL mix, enabling the HTL in the gas-and-HTL mix to heat the gas and isothermal expansion of the gas in the gas-and-HTL mix, limiting volume of the gas-and-HTL mix, thereby increasing pressure of the gas and causing acceleration of a flow of the gas-and-HTL mix, causing the gas-and-HTL mix to eject through a plurality of nozzles, thereby converting the heat of the HTL to kinetic energy to cause movement of the plurality of nozzles; and using the kinetic energy to produce mechanical work.

Abstract: A method for converting heat to mechanical work including providing incoming heat transfer fluid (HTF) at a first temperature to a mixing chamber, providing incoming compressed gas at a second temperature to the mixing chamber, enabling the gas and the HTF to mix, producing a gas-and-HTF mix, enabling the HTF in the gas-and-HTF mix to heat the gas and isothermal expansion of the gas in the gas-and-HTF mix, limiting volume of the gas-and-HTF mix, thereby increasing pressure of the gas and causing acceleration of a flow of the gas-and-HTF mix, causing the gas-and-HTF mix to eject through a nozzle, thereby converting the heat of the HTF to kinetic energy, and using the kinetic energy to produce mechanical work. Related apparatus and methods are also described.

Abstract: A system for generating light, comprises a spectral light source, characterized by a spectral line shape described by a visibility function; and a multimode waveguide, characterized by an optical path difference distribution described by a standard deviation. The standard deviation typically matches, within a predetermined tolerance, a location of a zero point of the visibility function at which a contrast of the visibility function is less than 0.1.

Abstract: A system for displaying a holographic image of an object behind a real object surface, including a computing unit for computing data for displaying a three-dimensional image of an object, a location measurement unit for measuring a location of a surface of a real object, a display for displaying the three dimensional image of the object, wherein the computing unit is adapted to compute data to display the three-dimensional image of the object at least partly behind the surface of the real object. Related apparatus and methods are also described.

Abstract: A system for displaying a holographic image of an object behind a real object surface, including a computing unit for computing data for displaying a three-dimensional image of an object, a location measurement unit for measuring a location of a surface of a real object, a display for displaying the three dimensional image of the object, wherein the computing unit is adapted to compute data to display the three-dimensional image of the object at least partly behind the surface of the real object. Related apparatus and methods are also described.

Abstract: A method for converting heat to mechanical work including providing incoming heat transfer fluid (HTF) at a first temperature to a mixing chamber, providing incoming compressed gas at a second temperature to the mixing chamber, enabling the gas and the HTF to mix, producing a gas- and- HTF mix, enabling the HTF in the gas- and- HTF mix to heat the gas and isotherma l expansion of the gas in the gas- and- HTF mix, limiting volume of the gas-and-HTF mix, thereby increasing pressure of the gas and causing acceleration of a flow of the gas-and-HTF mix, causing the gas-and-HTF mix to eject through a nozzle, thereby converting the heat of the HTF to kinetic energy, and using the kinetic energy to produce mechanical work. Related apparatus and methods are also described.

Abstract: A pupil tracking system including a light source for illuminating a viewer's eye, an aperture located to pass light from the light source after retro-reflection from the viewer's pupil, the aperture sized and shaped to pass the light from the light source and block at least a portion of other light arriving at the aperture, and a light sensor for tracking a location of a spot produced by the light from the light source which passed the aperture. Related apparatus and methods are also described.

Abstract: A display for displaying a wide Field of View (FoV) scene including a holographic image within the scene, including a first Spatial Light Modulator (SLM) and an optical system for producing a first holographic image at a center of a displayed scene, and a second image display for producing at least a first additional image adjacent to the first holographic image. In some embodiments an augmented reality display is used for the displaying of the first holographic image at the center of a field of view and the second image adjacent to the first holographic image. In some embodiments a virtual reality display is used for the displaying of the first holographic image near the center of a field of view and the second image adjacent to the first holographic image. Related apparatus and methods are also described.

Abstract: A method of producing a Computer Generated Hologram (CGH) for producing a 3 dimensional (3D) holographic image, including receiving data describing a 3D scene, producing a first CGH for producing a 2D image of the 3D scene as viewed from a specific viewing direction, the 2D image perpendicular to the viewing direction, decomposing the 2D image to a plurality of slices at different depths along the viewing direction, adjusting the first CGH by making, for at least one of the plurality of slices, a correction to the CGH associated with a depth of the slice along the viewing direction, thereby producing a corrected CGH for producing a 3D holographic image of the 3D scene. Related apparatus and methods are also described.

Abstract: A method of displaying a Computer Generated Holographic (CGH) image by a display, including setting pixel values of a Spatial Light Modulator (SLM) included in a Head Mounted Display (HMD), producing a interference based holographic image at a first location by projecting coherent light onto the SLM, and re-imaging the holographic image from the first location to form a holographic image in front of an eye of a viewer wearing the HMD. Related apparatus and methods are also described.

Abstract: Disclosed herein is a device comprised of: i) at least one substrate; (ii) a ceiling; (iii) one or more flow channels disposed between said substrate and said ceiling and configured to contain an actuation liquid; and (iv) one or more recesses distributed throughout at least said substrate and open to said flow channel and configured to contain a fluid; wherein 50% to 80% of the flow channel liquid-substrate interface, interfaces with said fluid within said recesses; and (v) at least one heating element, configured to heat one or more portions of the actuation liquid and generate a pressure and/or temperature gradient within said actuation liquid. Systems and uses of the device are further disclosed.

Abstract: A system for energy conversion including photoluminescent (PL) material for absorbing solar radiation and emitting PL radiation, a solar concentrator for concentrating solar radiation on the PL material, photovoltaic (PV) material configured to absorb the PL radiation, and a chamber for containing the PL material and Heat Transfer Fluid (HTF), and further including the system configured to pipe the HTF from the chamber to a system for conversion of HTF heat to energy. Related apparatus and methods are also described.

Abstract: A system for generating light, comprises a spectral light source, characterized by a spectral line shape described by a visibility function; and a multimode waveguide, characterized by an optical path difference distribution described by a standard deviation. The standard deviation typically matches, within a predetermined tolerance, a location of a zero point of the visibility function at which a contrast of the visibility function is less than 0.1.

Abstract: A method for providing tactile feedback in a display system including using a display to show an image of a virtual object in a viewing space, using a touch detector to detect a user touching a real object within the viewing space, and providing a location of the touching to the display. Related apparatus and methods are also described.

Abstract: A display for displaying a wide Field of View (FoV) scene including a holographic image within the scene, including a first Spatial Light Modulator (SLM) and an optical system for producing a first holographic image at a center of a displayed scene, and a second image display for producing at least a first additional image adjacent to the first holographic image. In some embodiments an augmented reality display is used for the displaying of the first holographic image at the center of a field of view and the second image adjacent to the first holographic image. In some embodiments a virtual reality display is used for the displaying of the first holographic image near the center of a field of view and the second image adjacent to the first holographic image. Related apparatus and methods are also described.

Abstract: A system for displaying a holographic image of an object behind a real object surface, including a computing unit for computing data for displaying a three-dimensional image of an object, a location measurement unit for measuring a location of a surface of a real object, a display for displaying the three dimensional image of the object, wherein the computing unit is adapted to compute data to display the three-dimensional image of the object at least partly behind the surface of the real object. Related apparatus and methods are also described.

Abstract: A method for directing non-modulated light from a Spatial Light Modulator (SLM) and allowing through modulated light for producing an interference based holographic image, the method including illuminating the SLM with coherent light, thereby producing a mix of light modulated by the SLM and light not modulated by the SLM, and projecting the mix of the modulated light and the not modulated light along an optical axis onto a volume grating, wherein the volume grating directs the not modulated light away from the holographic image and allows through modulated light for producing the holographic image. Related apparatus and methods are also described.

Abstract: A method of emitting photons at a desired wavelength, including: providing a material having a first region of high absorption of radiation at a first set of wavelength of radiation, contiguous with a second region of low absorption of radiation at a shorter set of wavelengths, and a third region of high emission at a further shorter set of wavelengths; applying energy to the material at the first region, such that most of an effective black body radiation of said material at a temperature of the material would fall within the second region and be configured to transfer energy to said third region and not overlap with the first region; and emitting energy from the material at the third region, powered by said applying energy.

Abstract: A display for displaying a wide Field of View (FoV) scene including a holographic image within the scene, including a first Spatial Light Modulator (SLM) and an optical system for producing a first holographic image at a center of a displayed scene, and a second image display for producing at least a first additional image adjacent to the first holographic image. In some embodiments an augmented reality display is used for the displaying of the first holographic image at the center of a field of view and the second image adjacent to the first holographic image. In some embodiments a virtual reality display is used for the displaying of the first holographic image near the center of a field of view and the second image adjacent to the first holographic image. Related apparatus and methods are also described.