Search Patents
  • Thin film filters using omnidirectional reflectors
    Patent number: 6624945
    Abstract: An electromagnetic wavelength filter that allows the transmission of electromagnetic energy within a narrow range of wavelengths while reflecting incident electromagnetic energy at other wavelengths. The filter includes at least one cavity region; and at least two reflectors surrounding the at least one cavity region, at least one of the reflectors being an omni-directional reflector. The omni-directional reflector includes a structure with a surface and an index of refraction variation perpendicular to the surface, and the omni-directional reflector is specifically configured to exhibit high omni-directional reflection for a predetermined range of frequencies of incident electromagnetic energy for any angle of incidence and any polarization.
    Type: Grant
    Filed: February 12, 2001
    Date of Patent: September 23, 2003
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, John D. Joannopoulos, George B. Kenney, Michal Lipson, Kevin M. Chen, Lionel C Kimerling
  • Slow-light fiber Bragg grating sensor
    Patent number: 8797540
    Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device can include a fiber Bragg grating and a narrowband optical source. The narrowband optical source can be configured to generate light. A first portion of light can be transmitted along a first optical path extending along and through the length of the fiber Bragg grating at a group velocity. The light can have a wavelength at or in the vicinity of a wavelength at which one or more of the following quantities is at a maximum value: (a) the product of the group index spectrum and a square root of the power transmission spectrum, (b) the slope of a product of the group index spectrum and one minus the power transmission spectrum, and (c) the slope of a product of the group index spectrum and the power transmission spectrum.
    Type: Grant
    Filed: September 2, 2011
    Date of Patent: August 5, 2014
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J. F. Digonnet, Shanhui Fan, He Wen, Matthew Terrel
  • 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
  • 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
  • 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
  • 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
  • SYSTEM AND METHOD FOR MEASURING PERTURBATIONS UTILIZING AN OPTICAL FILTER AND A NARROWBAND OPTICAL SOURCE
    Publication number: 20150211918
    Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.
    Type: Application
    Filed: April 3, 2015
    Publication date: July 30, 2015
    Inventors: He Wen, Michel J.F. Digonnet, Shanhui Fan
  • APPARATUSES AND METHODS INVOLVING THERMALLY TUNED COMPOSITE MATERIAL
    Publication number: 20210024143
    Abstract: An apparatus includes a substrate, at least one type of tuning material, and a composite material. The substrate has an interface surface or material that manifests, in response to light in a color spectrum, a particular color and a first thermal load. The particular color is associated with the first thermal load. The at least one type of tuning material manifests, in response to light in the color spectrum, the particular color and a second thermal load. The particular color is associated with the second thermal load. The first thermal load is different from the second thermal load. The composite material includes the interface surface or material and the at least one type of tuning material. The composite material manifests, in response to light in the color spectrum, the particular color and a tuned thermal load which is different than the first thermal load and the second thermal load.
    Type: Application
    Filed: March 29, 2019
    Publication date: January 28, 2021
    Inventors: Wei Li, Yu Shi, Shanhui Fan, Zhen Chen
  • 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
  • RADIATIVE COOLING WITH SOLAR SPECTRUM REFLECTION
    Publication number: 20220178628
    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: December 16, 2021
    Publication date: June 9, 2022
    Inventors: Aaswath Pattabhi Raman, Shanhui Fan, Eden Rephaeli, Linxiao Zhu, Marc A. Anoma, Eli Goldstein
  • 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
  • RADIATIVE COOLING WITH SOLAR SPECTRUM REFLECTION
    Publication number: 20240361089
    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: July 11, 2024
    Publication date: October 31, 2024
    Inventors: Aaswath Pattabhi Raman, Shanhui Fan, Eden Rephaeli, Linxiao Zhu, Marc A. Anoma, Eli Goldstein
  • RADIATIVE COOLING WITH SOLAR SPECTRUM REFLECTION
    Publication number: 20190017758
    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: September 19, 2018
    Publication date: January 17, 2019
    Inventors: Aaswath Pattabhi Raman, Shanhui Fan, Eden Rephaeli, Linxiao Zhu, Marc A. Anoma, Eli Goldstein
  • 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
  • Photonic crystal reflectors/filters and displacement sensing applications
    Patent number: 7155087
    Abstract: We introduce a mechanically tunable photonic crystal structure consisting of coupled photonic crystal slabs. Using both analytic theory, and first-principles finite-difference time-domain simulations, we demonstrate that the transmission and reflection coefficients for light normally incident upon such structures can be highly sensitive to nano-scale variations in the spacing between the slabs. Moreover, by specifically configuring the photonic crystal structures, the high sensitivity can be preserved in spite of significant fabrication-related disorders. We expect such a structure to play important roles in micro-mechanically tunable optical sensors and filters.
    Type: Grant
    Filed: October 8, 2003
    Date of Patent: December 26, 2006
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Wonjoo Suh, Mehmet Fatih Yanik, Olav Solgaard, Shanhui Fan
  • 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
  • Guided resonance dielectric filter systems
    Patent number: 7142364
    Abstract: We theoretically introduce a new type of optical all-pass filter based on guided resonance in coupled photonic crystal slabs. The filter exhibits near-complete transmission for both on- and off-resonant frequencies and yet generates large resonant group delay. We further show that such a filter can be mechanically switched into a flat-top band rejection filter. We also show that a single photonic crystal slab can also function either as optical all-pass transmission or flattop reflection filter for normally incident light. Both filter functions are synthesized by designing the spectral properties of guided resonance in the slab. The structure is extremely compact along the vertical direction.
    Type: Grant
    Filed: September 8, 2004
    Date of Patent: November 28, 2006
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Wonjoo Suh, Olav Solgaard, Shanhui Fan
  • 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
  • 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
  • System and method for measuring perturbations utilizing an optical filter and a narrowband optical source
    Patent number: 9347826
    Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.
    Type: Grant
    Filed: April 3, 2015
    Date of Patent: May 24, 2016
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: He Wen, Michel J. F. Digonnet, Shanhui Fan
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