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
  • High omnidirectional reflector
    Publication number: 20020060847
    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: Application
    Filed: September 14, 2001
    Publication date: May 23, 2002
    Inventors: John D. Joannopoulos, Shanhui Fan, Joshua N. Winn, Yoel Fink
  • 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
  • Low-loss resonator and method of making same
    Patent number: 6853789
    Abstract: A method of making a low-loss electromagnetic wave resonator structure. The method includes providing a resonator structure, the resonator structure including a confining device and a surrounding medium. The resonator structure supporting at least one resonant mode, the resonant mode displaying a near-field pattern in the vicinity of said confining device and a far-field radiation pattern away from the confining device. The surrounding medium supports at least one radiation channel into which the resonant mode can couple. The resonator structure is specifically configured to reduce or eliminate radiation loss from said resonant mode into at least one of the radiation channels, while keeping the characteristics of the near-field pattern substantially unchanged.
    Type: Grant
    Filed: June 19, 2001
    Date of Patent: February 8, 2005
    Inventors: Attila Mekis, Shanhui Fan, John D. Joannopoulos, Pierre Villeneuve
  • Optical sensor having a non-negligible source coherence length
    Patent number: 8437005
    Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical waveguide having a length and a laser source optically coupled to the waveguide. The laser source has a coherence length. Light from the source is transmitted to the waveguide as a first signal propagating along the waveguide in a first direction and a second signal propagating along the waveguide 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 waveguide 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: June 11, 2012
    Date of Patent: May 7, 2013
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J.F. Digonnet, Shanhui Fan, Seth Lloyd
  • SLOW-LIGHT FIBER BRAGG GRATING SENSOR
    Publication number: 20120086934
    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: Application
    Filed: September 2, 2011
    Publication date: April 12, 2012
    Applicant: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J.F. Digonnet, Shanhui Fan, He Wen, Matthew Terrel
  • Three-dimensional periodic dielectric structures having photonic bandgaps
    Patent number: 5440421
    Abstract: A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, each layer having a stratum of a first material having a first dielectric constant and a plurality of parallel grooves along a first axis lying in the plane of the layer, the grooves including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.
    Type: Grant
    Filed: May 10, 1994
    Date of Patent: August 8, 1995
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, Pierre R. Villeneuve, Robert D. Meade, John D. Joannopoulos
  • SYSTEMS AND METHODS FOR HEAT CONDUCTING AND BIOFLUID TRANSPORTING TEXTILE
    Publication number: 20210402734
    Abstract: Example implementations include a textile apparatus for transporting perspiration and heat, the textile apparatus including a substantially planar and heat-conducting substrate including at least one recess, and a textile film including one or more fibers disposed in contact with at least one substantially planar surface of the substrate and at least one surface of the recess. Example implementations also include a method of manufacturing a textile apparatus for transporting perspiration and heat, the method including forming a nanofiber solution, extruding one or more nanofibers from the nanofiber solution, forming one or more recesses in a substantially planar surface of a substrate, and integrating one or more of the nanofibers with the substantially planar surface of the substrate and at least one surface of the recesses.
    Type: Application
    Filed: June 24, 2021
    Publication date: December 30, 2021
    Applicant: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Yi Cui, Shanhui Fan, Yucan Peng, Wei Li, Bofei Liu
  • 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
  • Systems and methods for activation functions for photonic neural networks
    Patent number: 11460753
    Abstract: Systems and methods for activation in an optical circuit in accordance with embodiments of the invention are illustrated. One embodiment includes an optical activation circuit, wherein the circuit comprises a directional coupler, an optical-to-electrical conversion circuit, a time delay element, a nonlinear signal conditioner, and a phase shifter. The directional coupler receives an optical input and provides a first portion to the optical-to-electrical conversion circuit and a second portion to the time delay element, the time delay element provides a delayed signal to the phase shifter, and the optical-to-electrical conversion circuit converts an optical signal from the directional coupler to an electrical signal used to activate the phase shifter to shift the phase of the delayed signal.
    Type: Grant
    Filed: May 10, 2019
    Date of Patent: October 4, 2022
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Tyler William Hughes, Momchil Minkov, Ian Williamson, 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
  • 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
  • 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
  • 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
  • Three-dimensional periodic dielectric structures having photonic bandgaps
    Patent number: 5600483
    Abstract: A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, at least one layer having a stratum of a first material having a first dielectric constant and a plurality of parallel regions along a first axis lying in the plane of the layer, the regions including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: February 4, 1997
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, Pierre R. Villeneuve, John D. Joannopoulos, Robert D. Meade
  • 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
  • POLYMER-INORGANIC MULTILAYER DIELECTRIC FILM
    Publication number: 20010008693
    Abstract: A multilayer dielectric film structure includes a pair or plurality of materials at least one being a polymer and the other of high index of refraction inorganic material (compared to the polymer) at the wavelengths of interest. The structure is fabricated by a combination of layering techniques, one of which is used to create a layer of the polymer, the other being used to deposit the inorganic component. The assembly process yields a structure of alternating polymer and inorganic layers of high index of refraction (compared to air). The structure preferably will reflect light within a certain frequency range of any polarization and at a continuum of angles of incidence ranging from normal to oblique. In a particular embodiment of the invention, the structure includes alternating layers of a polymer, e.g., polystyrene and Tellurium.
    Type: Application
    Filed: March 12, 1999
    Publication date: July 19, 2001
    Inventors: YOEL FINK, EDWIN L. THOMAS, JOHN D. JOANNOPOULOS, CHIPING CHEN, JOSHUA N. WINN, SHANHUI FAN
  • LASER-DRIVEN OPTICAL GYROSCOPE HAVING A NON-NEGLIGIBLE SOURCE COHERENCE LENGTH
    Publication number: 20100302548
    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: Application
    Filed: April 26, 2010
    Publication date: December 2, 2010
    Inventors: Michel J.F. Digonnet, Shanhui Fan, Seth Lloyd
  • OPTICAL SENSOR HAVING A NON-NEGLIGIBLE SOURCE COHERENCE LENGTH
    Publication number: 20120281225
    Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical waveguide having a length and a laser source optically coupled to the waveguide. The laser source has a coherence length. Light from the source is transmitted to the waveguide as a first signal propagating along the waveguide in a first direction and a second signal propagating along the waveguide 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 waveguide 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: Application
    Filed: June 11, 2012
    Publication date: November 8, 2012
    Applicant: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J.F. Digonnet, Shanhui Fan, Seth Lloyd
  • Photonic crystal reflectors/filters and displacement sensing applications
    Patent number: 7412127
    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: August 15, 2006
    Date of Patent: August 12, 2008
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Wonjoo Suh, Mehmet Fatih Yanik, Olav Solgaard, Shanhui Fan
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