Patents by Inventor Todd H. Stievater

Todd H. Stievater has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20140260535
    Abstract: A chemical detector for rapid, simultaneous detection of multiple chemicals including chemical warfare agents, toxic industrial chemicals, and explosives having one or more gas chromatography columns each with a chemosorbent or a chemo-reactive stationary phase and an infrared-transparent base, a bright infrared light source, a mechanism to direct the light source to any point along any of the columns, and an infrared sensor. Another disclosed detector has one or more gas chromatography columns each on the surface of a substrate having at least one infrared-transparent waveguide pattern, a bright infrared light source, and at least one ring resonator for each column, where each ring resonator is coated with a chemosorbent or a chemo-reactive stationary phase, and where each ring resonator spectroscopically probes the stationary phase. Also disclosed are the related methods for chemical detection.
    Type: Application
    Filed: March 13, 2014
    Publication date: September 18, 2014
    Inventors: R. Andrew McGill, Robert Furstenberg, Viet K. Nguyen, Chris Kendziora, Michael Papantonakis, Todd H. Stievater
  • Publication number: 20130330232
    Abstract: A mass sensor system including multiple Fabry-Perot microcavities connected in parallel by multiple waveguides. Each of the mass sensors includes a microbridge having a fundamental resonance frequency, and a movable reflective mirror etched into the microbridge; a fixed reflective mirror etched in a substrate, the fixed reflective mirror being fixed to the substrate in a region spaced apart from the movable reflective mirror; and an optical waveguide etched in the substrate that connects the movable mirror and the fixed mirror forming the Fabry-Perot microcavity interferometer. The system includes a tunable continuous-wave laser operative to optically interrogate the Fabry-Perot microcavity of each of the plurality of mass sensors, and a receiver operative to receive sensor signals from each of the plurality of mass sensors, the sensor signals comprising reflective signals and transmitted signals.
    Type: Application
    Filed: July 18, 2013
    Publication date: December 12, 2013
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Marcel W. Pruessner, Todd H. Stievater, William S. Rabinovich
  • Publication number: 20130294719
    Abstract: A waveguide device for frequency mixing or conversion through birefringent phase matching, having a horizontal waveguide suspended above a substrate. The waveguide is formed of a zinc blende type III-V semiconductor material with a high nonlinear susceptibility.
    Type: Application
    Filed: April 22, 2013
    Publication date: November 7, 2013
    Applicant: The Government of the US, as represented by the Secretary of the Navy
    Inventors: Todd H. Stievater, Jacob B. Khurgin, Doewon Park, Marcel W. Pruessner, William S. Rabinovich, Rita Mahon
  • Patent number: 8542365
    Abstract: A change in mass of a microbridge in a mass sensor can be sensed by applying a time-varying amplitude modulated electrostatic force to excite the microbridge into resonance at the frequency of amplitude modulation. An optical energy is then transmitted at a wavelength close to a resonant wavelength of a Fabry-Perot microcavity, which is formed by etching a movable reflective mirror into a region of the microbridge and by etching a fixed reflective minor in a region spaced apart from the microbridge. The two mirrors are interconnected by an optical waveguide. The movable mirror and fixed mirror reflect the optical energy to a receiver, and a change in the Fabry-Perot microcavity's reflectivity is interferometrically determined. The change in reflectivity indicates a change in the microbridge's resonant frequency due to increased mass of the microbridge resulting from sorption of a target chemical by a layer of chemoselective material deposited on the microbridge.
    Type: Grant
    Filed: March 23, 2010
    Date of Patent: September 24, 2013
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Marcel W. Pruessner, Todd H. Stievater, William S Rabinovich
  • Patent number: 8459123
    Abstract: Micro-opto-mechanical chemical sensors and methods for simultaneously detecting and discriminating between a variety of vapor-phase analytes. One embodiment of the sensor is a photonic microharp chemical sensor with an array of closely spaced microbridges, each differing slightly in length and coated with a different sorbent polymer. The microbridges can be excited photothermally, and the microbridges can be optically interrogated using microcavity interferometry. Other actuation methods include piezoelectric, piezoresistive, electrothermal, and magnetic. Other read-out techniques include using a lever arm and other interferometric techniques.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: June 11, 2013
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Todd H. Stievater, William S Rabinovich, Nicolas A Papanicolaou, Robert Bass, Jennifer L Stepnowski, R Andrew McGill
  • Patent number: 8427738
    Abstract: A waveguide device for frequency mixing or conversion through birefringent phase matching, having two suspended horizontal waveguides with an air-filled horizontal nanoslot between them. The waveguides are formed of a material with a high nonlinear susceptibility, and one waveguide can be n-doped with the other waveguide slab being p-doped. The system can be tuned to operate at different frequencies by varying the nanoslot gap distance by electrostatically actuating the suspended air-clad waveguides.
    Type: Grant
    Filed: October 8, 2010
    Date of Patent: April 23, 2013
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Todd H. Stievater, Jacob B. Khurgin, Doewon Park, Marcel W. Pruessner, William S. Rabinovich
  • Publication number: 20110188112
    Abstract: A waveguide device for frequency mixing or conversion through birefringent phase matching, having two suspended horizontal waveguides with an air-filled horizontal nanoslot between them. The waveguides are formed of a material with a high nonlinear susceptibility, and one waveguide can be n-doped with the other waveguide slab being p-doped. The system can be tuned to operate at different frequencies by varying the nanoslot gap distance by electrostatically actuating the suspended air-clad waveguides.
    Type: Application
    Filed: October 8, 2010
    Publication date: August 4, 2011
    Inventors: Todd H. Stievater, Jacob B. Khurgin, Doewon Park, Marcel W. Pruessner, William S. Rabinovich
  • Publication number: 20100238454
    Abstract: A change in mass of a microbridge in a mass sensor can be sensed by applying a time-varying amplitude modulated electrostatic force to excite the microbridge into resonance at the frequency of amplitude modulation. An optical energy is then transmitted at a wavelength close to a resonant wavelength of a Fabry-Perot microcavity, which is formed by etching a movable reflective mirror into a region of the microbridge and by etching a fixed reflective minor in a region spaced apart from the microbridge. The two mirrors are interconnected by an optical waveguide. The movable mirror and fixed mirror reflect the optical energy to a receiver, and a change in the Fabry-Perot microcavity's reflectivity is interferometrically determined. The change in reflectivity indicates a change in the microbridge's resonant frequency due to increased mass of the microbridge resulting from sorption of a target chemical by a layer of chemoselective material deposited on the microbridge.
    Type: Application
    Filed: March 23, 2010
    Publication date: September 23, 2010
    Inventors: Marcel W. Pruessner, Todd H. Stievater, William S. Rabinovich
  • Publication number: 20100139406
    Abstract: Micro-opto-mechanical chemical sensors and methods for simultaneously detecting and discriminating between a variety of vapor-phase analytes. One embodiment of the sensor is a photonic microharp chemical sensor with an array of closely spaced microbridges, each differing slightly in length and coated with a different sorbent polymer. The microbridges can be excited photothermally, and the microbridges can be optically interrogated using microcavity interferometry. Other actuation methods include piezoelectric, piezoresistive, electrothermal, and magnetic. Other read-out techniques include using a lever arm and other interferometric techniques.
    Type: Application
    Filed: September 29, 2009
    Publication date: June 10, 2010
    Applicant: The Government of the US. as represented by the Secretary of the Navy
    Inventors: Todd H. Stievater, William S. Rabinovich, Nicolas A. Papanicolaou, Robert Bass, Jennifer L. Stepnowski, R. Andrew McGill
  • Patent number: 7673517
    Abstract: A sensor and a method for sensing a change in mass of a reflective microbeam in a sensor, the sensor having a reflective layer disposed on a substrate and spaced apart from the reflective microbeam. The microbeam receives amplitude modulated laser energy at a first wavelength and is photothermally excited into resonance at the frequency of amplitude modulation, the reflective microbridge and the reflective layer receive optical energy at a second wavelength and reflect the optical energy toward a receiver. A change in reflectivity of the microbeam at different frequencies is determined. A change in reflectivity indicates a change in resonant frequency of the microbeam. Mass of the microbeam changes when a chemoselective material on the microbeam sorbs a target chemical.
    Type: Grant
    Filed: November 13, 2006
    Date of Patent: March 9, 2010
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Todd H. Stievater, William S Rabinovich, Eric J Houser, Stanley V. Stepnowski, R Andrew McGill