Search Patents
  • RADIATIVE COOLING WITH SOLAR SPECTRUM REFLECTION
    Publication number: 20150338175
    Abstract: Various aspects as described herein are directed to a radiative cooling apparatuses and methods for cooling an object. As consistent with one or more embodiments, a radiative cooling apparatus includes an arrangement of a plurality of different material located at different depths along a depth dimension relative to the object. The plurality of different material includes a solar spectrum reflecting portion configured and arranged to suppress light modes, thereby inhibiting coupling of the incoming electromagnetic radiation, of at least some wavelengths in the solar spectrum, to the object at a range of angles of incidence relative to the depth dimension. Further, the plurality of material includes a thermally-emissive arrangement configured and arranged to facilitate, simultaneously with the inhibiting coupling of the incoming electromagnetic radiation, the thermally-generated electromagnetic emissions from the object at the range of angles of incidence and in mid-IR wavelengths.
    Type: Application
    Filed: May 21, 2015
    Publication date: November 26, 2015
    Inventors: Aaswath Pattabhi Raman, Shanhui Fan, Eden Rephaeli, Linxiao Zhu, Marc Anoma, Eli Goldstein
  • Tunable microcavity and method of using nonlinear materials in a photonic crystal
    Patent number: 6058127
    Abstract: A nonlinear dielectric material is incorporated within a photonic crystal as a means of changing the refractive index of a defect. In this way, the resonant frequency can be easily adjusted, after fabrication, by external mechanisms (either optical or electronic). The ability to tune the frequency of a resonant mode is useful for constructing photonic integrated devices, thus the invention enables the use of a photonic-crystal microcavity for such purposes. In one embodiment there is provided a photonic crystal having a periodic dielectric structure, and a defect positioned within the structure to define a microcavity. The defect includes a nonlinear material and being adapted to have an induced variation in index of refraction so as to tune the resonant mode of the microcavity.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: May 2, 2000
    Assignee: Massachusetts Institute of Technology
    Inventors: John D. Joannopoulos, Pierre R. Villeneuve, Shanhui Fan, Daniel S. Abrams
  • IMAGE SENSORS INCLUDING META-STRUCTURE FOR COLOR SEPARATION AND ELECTRONIC DEVICES INCLUDING IMAGE SENSOR
    Publication number: 20230352506
    Abstract: The present disclosure provides meta-optical elements and image sensors using a meta-pattern and apparatuses including the image sensors. In an embodiment, an image sensor includes a plurality of pixels. Each pixel of the plurality of pixels includes a photoelectric conversion layer including at least one photoelectric conversion element, and a color routing meta-structure layer provided at a position facing the photoelectric conversion layer. The color routing meta-structure layer includes a meta-structure having a symmetrical structure with respect to a center of a corresponding pixel, and a multi-layer structure having a refractive index that varies in a direction perpendicular to a light-incident surface.
    Type: Application
    Filed: May 2, 2023
    Publication date: November 2, 2023
    Applicants: SAMSUNG ELECTRONICS CO., LTD., THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIVERSITY
    Inventors: Sungmo AHN, Sangeun Mun, Shanhui Fan, Peter Bert Catrysse, Hongkyu Park, Minwoo Lim, Choonlae Cho
  • THERMAL RECTIFICATION DEVICE
    Publication number: 20150082810
    Abstract: The first and second media are coupled via evanescent waves generated by surface phonon polaritons thermally excited on surfaces of the first and second media. First and second media made of the same material are disposed with a gap formed between for cutting off thermal conduction and the heat transfer between them is performed via the thermally excited evanescent waves. A third medium is provided on a surface of the first medium on a side toward the second medium. Heat flux flows from the second medium to the first medium in a first state wherein the second medium has a first temperature TH and the first medium has a second temperature TL lower than the TH differ in intensity from heat flux which flows from the first to the second medium in a second state wherein the first medium has the TH and the second medium has the TL.
    Type: Application
    Filed: April 16, 2013
    Publication date: March 26, 2015
    Applicant: KABUSHIKI KAISHA TOYOTA CHUO KENKYUSHO
    Inventors: Hideo Iizuka, Shanhui Fan
  • High omnidirectional reflector
    Patent number: 6903873
    Abstract: A reflector, a method of producing same and a method of creating high omnidirectional reflection for a predetermined range of frequencies of incident electromagnetic energy for any angle of incidence and any polarization. The reflector includes a structure with a surface and a refractive index variation along the direction perpendicular to the surface while remaining nearly uniform along the surface. The structure is configured such that i) a range of frequencies exists defining a photonic band gap for electromagnetic energy incident along the perpendicular direction of said surface, ii) a range of frequencies exists defining a photonic band gap for electromagnetic energy incident along a direction approximately 90° from the perpendicular direction of said surface, and iii) a range of frequencies exists which is common to both of said photonic band gaps. In an exemplary embodiment, the reflector is configured as a photonic crystal.
    Type: Grant
    Filed: August 8, 2000
    Date of Patent: June 7, 2005
    Assignee: OmniGuide Communications
    Inventors: John D. Joannopoulos, Shanhui Fan, Joshua N. Winn, Yoel Fink
  • OMNIDIRECTIONAL MULTILAYER DEVICE FOR ENHANCED OPTICAL WAVEGUIDING
    Publication number: 20020025130
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Application
    Filed: October 14, 1999
    Publication date: February 28, 2002
    Inventors: YOEL FINK, SHANHUI FAN, JOHN D. JOANNOPOULOS, CHIPING CHEN, EDWIN L. THOMAS
  • Ultrahigh-Performance Radiative Cooler
    Publication number: 20180023866
    Abstract: A radiative cooler is provided having a thermally insulated vacuum chamber housing that is configured to support a vacuum level of at least 10-5 Torr, an infared-transparent window that is sealably disposed on top of the thermally insulated vacuum chamber and is transparet in the range of 8-13 ?m, a selective emitter disposed inside the chamber, a mirror cone on the infared-transparent window, a selective emitter inside the chamber and is configured to passively dissipate heat from the earth into outer space through the infared-transparent window and is thermally decoupled from ambient air and solar irradiation but coupled to outer space, a heat exchanger with inlet and outlet pipes disposed below the selective emitter to cool water flowing through the pipe, a sun shade disposed vertically outside the chamber to minimize direct solar irradiation, and a mirror cone to minimize downward atmospheric radiation.
    Type: Application
    Filed: July 17, 2017
    Publication date: January 25, 2018
    Inventors: Zhen Chen, Linxiao Zhu, Aaswath Raman, Eli A. Goldstein, Shanhui Fan
  • Creating large bandwidth line defects by embedding dielectric waveguides into photonic crystal slabs
    Publication number: 20040001683
    Abstract: We introduce a general designing procedure that allows us, for any given photonic crystal slab, to create an appropriate line defect structure that possesses single-mode bands with large bandwidth and low dispersion within the photonic band gap region below the light line. This procedure involves designing a high index dielectric waveguide that is phase matched with the gap of the photonic crystal slab, and embedding the dielectric waveguide as a line defect into a crystal in a specific configuration that is free of edge states within the guiding bandwidth. As an example, we show a single mode line defect waveguide with a bandwidth approaching 13% of the center-band frequency, and with a linear dispersion relation throughout most of the bandwidth.
    Type: Application
    Filed: November 8, 2002
    Publication date: January 1, 2004
    Applicant: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Wah Tung Lau, Shanhui Fan
  • Omnidirectional multilayer device for enhanced optical waveguiding
    Publication number: 20020191929
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Application
    Filed: August 1, 2002
    Publication date: December 19, 2002
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Photonic-bandgap fiber with a core ring
    Publication number: 20050281522
    Abstract: A photonic-bandgap fiber includes a photonic crystal lattice with a first material having a first refractive index and a pattern of a second material formed therein. The second material has a second refractive index lower than the first refractive index. The photonic crystal lattice has a plurality of first regions that support intensity lobes of the highest frequency bulk mode and has a plurality of second regions that do not support intensity lobes of the highest frequency bulk mode. The photonic-bandgap fiber further includes a central core formed in the photonic crystal lattice. The photonic-bandgap fiber further includes a core ring having an outer perimeter. The core ring surrounds the central core, wherein the outer perimeter of the core ring passes only through the second regions of the photonic crystal lattice.
    Type: Application
    Filed: May 6, 2005
    Publication date: December 22, 2005
    Inventors: Hyang Kim, Shanhui Fan, Gordon Kino, Jonghwa Shin, Michel Digonnet, Vinayak Dangui
  • Color-routers for Image Sensing
    Publication number: 20230417960
    Abstract: The present disclosure is directed toward systems for providing color-selective light detection and/or image sensing in a substantially lossless manner, thereby providing higher and up to nearly perfect optical efficiency. Embodiments disclosed herein include a plurality of pixel-repeat units, each including a color router that is configured to selectively route photons of each wavelength signal in a light signal to a different photodetector of the pixel-repeat unit. In some embodiments, the color router also functions as an anti-reflection coating that mitigates reflection of incident light, as well as a lensing system that directs substantially all photons of each wavelength signal only to their corresponding photodetector. As a result, the photodetectors collect more light than possible using prior-art absorptive color filters, thereby enabling smaller photodetectors to be used. Therefore, scaling of image sensor photodetectors to sub-wavelength sizes is possible.
    Type: Application
    Filed: November 2, 2021
    Publication date: December 28, 2023
    Inventors: Nathan ZHAO, Peter B. CATRYSSE, Shanhui FAN
  • Thermal rectification device
    Patent number: 9791183
    Abstract: The first and second media are coupled via evanescent waves generated by surface phonon polaritons thermally excited on surfaces of the first and second media. First and second media made of the same material are disposed with a gap formed between for cutting off thermal conduction and the heat transfer between them is performed via the thermally excited evanescent waves. A third medium is provided on a surface of the first medium on a side toward the second medium. Heat flux flows from the second medium to the first medium in a first state wherein the second medium has a first temperature TH and the first medium has a second temperature TL lower than the TH differ in intensity from heat flux which flows from the first to the second medium in a second state wherein the first medium has the TH and the second medium has the TL.
    Type: Grant
    Filed: April 16, 2013
    Date of Patent: October 17, 2017
    Assignee: KABUSHIKI KAISHA TOYOTA CHUO KENKYUSHO
    Inventors: Hideo Iizuka, Shanhui Fan
  • Metallodielectric photonic crystal
    Patent number: 5990850
    Abstract: A metallodielectric photonic crystal including a plurality of elements, each having a non-dielectric component, arranged with respect to each other in a three-dimensionally periodic lattice. The non-dielectric components being spatially isolated from one another, the lattice exhibiting a band gap in the spectrum of electromagnetic radiation modes propagating through said lattice. A support structure positions the elements in the three-dimensionally periodic lattice. In an exemplary embodiment, the elements are metallic spheres arranged within dielectric material. The three-dimensionally periodic lattice can include a face-centered-cubic lattice which exhibits a unidirectional photonic band gap, or a diamond lattice which exhibits an omnidirectional photonic band gap. The diamond lattice structure includes a gap width to midgap frequency ratio which can exceed 60%.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: November 23, 1999
    Assignee: Massachusetts Institute of Technology
    Inventors: Elliott R. Brown, John D. Joannopoulos, Shanhui Fan, Pierre R. Villeneuve, Oliver B. McMahon
  • Laser-driven optical gyroscope having a non-negligible source coherence length
    Patent number: 8223340
    Abstract: A fiber-optic sensor, a method of configuring a fiber-optic sensor, and a method of using a fiber-optic sensor are provided. The fiber-optic sensor includes an optical fiber coil having a length and a laser source optically coupled to the coil. The laser source has a coherence length. Light from the source is transmitted to the coil as a first signal propagating along the coil in a first direction and a second signal propagating along the coil in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the coil to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.
    Type: Grant
    Filed: April 26, 2010
    Date of Patent: July 17, 2012
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J. F. Digonnet, Shanhui Fan, Seth Lloyd
  • Omnidirectional multilayer device for enhanced optical waveguiding
    Patent number: 6603911
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Grant
    Filed: August 1, 2002
    Date of Patent: August 5, 2003
    Assignee: Massachusetts Institute of Technology
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Omnidirectional multilayer device for enhanced optical waveguiding
    Patent number: 6463200
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: October 8, 2002
    Assignee: Massachusetts Institute of Technology
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Training Wave-Based Physical Systems as Recurrent Neural Networks
    Publication number: 20220237347
    Abstract: A method is disclosed for designing an analog computer that implements a trained recurrent neural network. A computer simulates a wave-based physical system including a wave propagation domain, a boundary layer that approximates a boundary condition, a source of waves, probes for measuring properties of propagated waves, a material within a central region of the wave propagation domain. The simulation also includes a discretized numerical model of a differential equation describing dynamics of wave propagation in the physical system.
    Type: Application
    Filed: April 19, 2020
    Publication date: July 28, 2022
    Inventors: Tyler William Hughes, Ian A.D. Williamson, Momchil Minkov, Shanhui Fan
  • Radiative cooling with solar spectrum reflection
    Patent number: 10088251
    Abstract: Various aspects as described herein are directed to a radiative cooling apparatuses and methods for cooling an object. As consistent with one or more embodiments, a radiative cooling apparatus includes an arrangement of a plurality of different material located at different depths along a depth dimension relative to the object. The plurality of different material includes a solar spectrum reflecting portion configured and arranged to suppress light modes, thereby inhibiting coupling of the incoming electromagnetic radiation, of at least some wavelengths in the solar spectrum, to the object at a range of angles of incidence relative to the depth dimension. Further, the plurality of material includes a thermally-emissive arrangement configured and arranged to facilitate, simultaneously with the inhibiting coupling of the incoming electromagnetic radiation, the thermally-generated electromagnetic emissions from the object at the range of angles of incidence and in mid-IR wavelengths.
    Type: Grant
    Filed: May 21, 2015
    Date of Patent: October 2, 2018
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Aaswath Pattabhi Raman, Shanhui Fan, Eden Rephaeli, Linxiao Zhu, Marc Anoma, Eli Goldstein
  • Creating large bandwidth line defects by embedding dielectric waveguides into photonic crystal slabs
    Patent number: 6957003
    Abstract: We introduce a general designing procedure that allows us, for any given photonic crystal slab, to create an appropriate line defect structure that possesses single-mode bands with large bandwidth and low dispersion within the photonic band gap region below the light line. This procedure involves designing a high index dielectric waveguide that is phase matched with the gap of the photonic crystal slab, and embedding the dielectric waveguide as a line defect into a crystal in a specific configuration that is free of edge states within the guiding bandwidth. As an example, we show a single mode line defect waveguide with a bandwidth approaching 13% of the center-band frequency, and with a linear dispersion relation throughout most of the bandwidth.
    Type: Grant
    Filed: November 8, 2002
    Date of Patent: October 18, 2005
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Wah Tung Lau, Shanhui Fan
  • Radiative cooling with solar spectrum reflection
    Patent number: 11215407
    Abstract: Various aspects as described herein are directed to a radiative cooling apparatuses and methods for cooling an object. As consistent with one or more embodiments, a radiative cooling apparatus includes an arrangement of a plurality of different material located at different depths along a depth dimension relative to the object. The plurality of different material includes a solar spectrum reflecting portion configured and arranged to suppress light modes, thereby inhibiting coupling of the incoming electromagnetic radiation, of at least some wavelengths in the solar spectrum, to the object at a range of angles of incidence relative to the depth dimension. Further, the plurality of material includes a thermally-emissive arrangement configured and arranged to facilitate, simultaneously with the inhibiting coupling of the incoming electromagnetic radiation, the thermally-generated electromagnetic emissions from the object at the range of angles of incidence and in mid-IR wavelengths.
    Type: Grant
    Filed: September 19, 2018
    Date of Patent: January 4, 2022
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Aaswath Pattabhi Raman, Shanhui Fan, Eden Rephaeli, Linxiao Zhu, Marc A. Anoma, Eli Goldstein
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