Patents by Inventor Narasimha S. Prasad
Narasimha S. Prasad 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).
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Patent number: 11119072Abstract: A system for monitoring vibrations in a target region of interest may include a pulsed laser transmitter assembly, interferometric, telescope, and receiver optics, a photo-EMF detector assembly, signal conditioning/processing electronics, and a monitoring circuit/display. The detector assembly, which has a photo-EMF detector and amplifier circuits, generates an output signal indicative of the vibrations. A laser module outputs a source beam at a PRF of at least 2 Hz. A beam splitter device splits the source beam into separate interrogating and reference beams. The mirror directs the reference beam onto the photo-EMF detector for interference with a reflected return signal. The telescope optics generates an amplified return signal, and directs the amplified return signal to the photo-emf detector. The monitoring computer compares the output signal from the signal processor to a baseline to ascertain a difference therebetween, and generates a diagnostic signal indicative of the difference.Type: GrantFiled: August 9, 2019Date of Patent: September 14, 2021Assignee: UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASAInventor: Narasimha S. Prasad
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Publication number: 20200049666Abstract: A system for monitoring vibrations in a target region of interest may include a pulsed laser transmitter assembly, interferometric, telescope, and receiver optics, a photo-EMF detector assembly, signal conditioning/processing electronics, and a monitoring circuit/display. The detector assembly, which has a photo-EMF detector and amplifier circuits, generates an output signal indicative of the vibrations. A laser module outputs a source beam at a PRF of at least 2 Hz. A beam splitter device splits the source beam into separate interrogating and reference beams. The mirror directs the reference beam onto the photo-EMF detector for interference with a reflected return signal. The telescope optics generates an amplified return signal, and directs the amplified return signal to the photo-emf detector. The monitoring computer compares the output signal from the signal processor to a baseline to ascertain a difference therebetween, and generates a diagnostic signal indicative of the difference.Type: ApplicationFiled: August 9, 2019Publication date: February 13, 2020Inventor: Narasimha S. Prasad
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Publication number: 20180292309Abstract: A laser vibrometer for measurement of ambient chemical species includes a laser that produces a beam that is split into a reference readout beam and a signal readout beam. A probe laser beam is tuned to an absorption feature of a molecular transition, and generates acoustic signals when incident on a gaseous species via the photo acoustic effect. The scattered acoustic signals are incident on a thin membrane that vibrates. The readout laser beam reflected from the vibrating membrane is mixed with the reference beam at the surface of a photo-EMF detector. Interferrometric fringes are generated at the surface of the photo-EMF detector. Electric current is generated in the photo-EMF detector when the fringes are in motion due to undulations in the signal readout beam imparted by the vibrating membrane. A highly sensitive photo-EMF detector is capable of detecting picoJoules or less laser energy generated by vibrating processes.Type: ApplicationFiled: June 11, 2018Publication date: October 11, 2018Inventor: Narasimha S. Prasad
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Patent number: 9995674Abstract: A laser vibrometer for measurement of ambient chemical species includes a laser that produces a beam that is split into a reference readout beam and a signal readout beam. A probe laser beam is tuned to an absorption feature of a molecular transition, and generates acoustic signals when incident on a gaseous species via the photo acoustic effect. The scattered acoustic signals are incident on a thin membrane that vibrates. The readout laser beam reflected from the vibrating membrane is mixed with the reference beam at the surface of a photo-EMF detector. Interferrometric fringes are generated at the surface of the photo-EMF detector. Electric current is generated in the photo-EMF detector when the fringes are in motion due to undulations in the signal readout beam imparted by the vibrating membrane. A highly sensitive photo-EMF detector is capable of detecting picoJoules or less laser energy generated by vibrating processes.Type: GrantFiled: December 29, 2014Date of Patent: June 12, 2018Assignee: THE UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA.Inventor: Narasimha S. Prasad
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Publication number: 20180095026Abstract: A laser vibrometer for measurement of ambient chemical species includes a laser that produces a beam that is split into a reference readout beam and a signal readout beam. A probe laser beam is tuned to an absorption feature of a molecular transition, and generates acoustic signals when incident on a gaseous species via the photo acoustic effect. The scattered acoustic signals are incident on a thin membrane that vibrates. The readout laser beam reflected from the vibrating membrane is mixed with the reference beam at the surface of a photo-EMF detector. Interferrometric fringes are generated at the surface of the photo-EMF detector. Electric current is generated in the photo-EMF detector when the fringes are in motion due to undulations in the signal readout beam imparted by the vibrating membrane. A highly sensitive photo-EMF detector is capable of detecting picoJoules or less laser energy generated by vibrating processes.Type: ApplicationFiled: December 29, 2014Publication date: April 5, 2018Inventor: Narasimha S. Prasad
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Patent number: 8605262Abstract: A continuous wave Light Detection and Ranging (CW LiDAR) system utilizes two or more laser frequencies and time or range shifted pseudorandom noise (PN) codes to discriminate between the laser frequencies. The performance of these codes can be improved by subtracting out the bias before processing. The CW LiDAR system may be mounted to an artificial satellite orbiting the earth, and the relative strength of the return signal for each frequency can be utilized to determine the concentration of selected gases or other substances in the atmosphere.Type: GrantFiled: June 23, 2011Date of Patent: December 10, 2013Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventors: Joel F. Campbell, Narasimha S. Prasad, Fenton W. Harrison, Michael A. Flood
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Publication number: 20110317147Abstract: A continuous wave Light Detection and Ranging (CW LiDAR) system utilizes two or more laser frequencies and time or range shifted pseudorandom noise (PN) codes to discriminate between the laser frequencies. The performance of these codes can be improved by subtracting out the bias before processing. The CW LiDAR system may be mounted to an artificial satellite orbiting the earth, and the relative strength of the return signal for each frequency can be utilized to determine the concentration of selected gases or other substances in the atmosphere.Type: ApplicationFiled: June 23, 2011Publication date: December 29, 2011Applicant: U.S.A. as represented by the Administrator of the National Aeronautics and Space AdministrationInventors: Joel F. Campbell, Narasimha S. Prasad, Fenton W. Harrison, Michael A. Flood
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Patent number: 7042631Abstract: Power scalable, rectangular, multi-mode, self-imaging, waveguide technologies are used with various combination of large aperture configurations, 20, 50, 80, 322, 324, 326, 328, 330, 332, 334, 336, 338, Gaussian 360 and super-Gaussian 350 beam profiles, thermal management configurations 100, flared 240 and tapered 161 waveguide shapes, axial or zig-zag light propagation paths, diffractive wall couplers 304, 306, 308, 310, 312, 314, 316, 318, 320 and phase controller 200, flexibility 210, phased arrays 450, 490, beam combiners 530, 530?, and separators 344, 430, and other features to generate, transport, and deliver high power laser beams.Type: GrantFiled: April 5, 2002Date of Patent: May 9, 2006Assignee: Coherent Technologies, Inc.Inventors: Duane D. Smith, Wayne S. Pelouch, Narasimha S. Prasad, Josef Unternährer, John Koroshetz, Iain McKinnie
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Patent number: 6894828Abstract: The present invention is directed to guided wave systems, beam transport and waveguide techniques. The invention may comprise passive or active, hollow and dielectric core self-imaging mode wave guide systems, beam amplifiers (10, 40), laser resonators (70), beam transports, and waveguides. Embodiments may include rectangular cross-section waveguides, and preferably maintaining spatial profile of an input beam, such as a Gaussian beam, through the self-imaging period of the waveguide while unique new capabilities to mitigate non-linear distortions that corrupt spatial, spectral and temporal coherence and polarization. Additional aspects may include, for example, transport, amplification, phase/frequency control or modulation, deflection, conversion, synthetic aperture, distributed aperture, beam forming, beam steering, beam combining, power sampling, power combining and power splitting, among other features.Type: GrantFiled: October 1, 2001Date of Patent: May 17, 2005Assignee: Coherent Technologies, Inc.Inventors: Wayne S. Pelouch, Duane D. Smith, Narasimha S. Prasad
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Publication number: 20040008405Abstract: The present invention is directed to guided wave systems, beam transport and waveguide techniques. The invention may comprise passive or active, hollow and dielectric core self-imaging mode wave guide systems, beam amplifiers (10, 40), laser resonators (70), beam transports, and waveguides. Embodiments may include rectangular cross-section waveguides, and preferably maintaining spatial profile of an input beam, such as a Gaussian beam, through the self-imaging period of the waveguide while unique new capabilities to mitigate non-linear distortions that corrupt spatial, spectral and temporal coherence and polarization. Additional aspects may include, for example, transport, amplification, phase/frequency control or modulation, deflection, conversion, synthetic aperture, distributed aperture, beam forming, beam steering, beam combining, power sampling, power combining and power splitting, among other features.Type: ApplicationFiled: October 1, 2001Publication date: January 15, 2004Applicant: Coherent Technologies, Inc.Inventors: Wayne S. Pelouch, Duane D. Smith, Narasimha S. Prasad
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Publication number: 20030063884Abstract: Power scalable, rectangular, multi-mode, self-imaging, waveguide technologies are used with various combination of large aperture configurations, 20, 50, 80, 322, 324, 326, 328, 330, 332, 334, 336, 338, Gaussian 360 and super-Gaussian 350 beam profiles, thermal management configurations 100, flared 240 and tapered 161 waveguide shapes, axial or zig-zag light propagation paths, diffractive wall couplers 304, 306, 308, 310, 312, 314, 316, 318, 320 and phase controller 200, flexibility 210, phased arrays 450, 490, beam combiners 530, 530′, and separators 344, 430, and other features to generate, transport, and deliver high power laser beams.Type: ApplicationFiled: April 5, 2002Publication date: April 3, 2003Inventors: Duane D. Smith, Wayne S. Pelouch, Narasimha S. Prasad, Josef Unternahrer, John Koroshetz, Iain McKinnie
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Patent number: 5291503Abstract: An optical parametric oscillator/laser system includes an optical pump source for generating pump radiation and an embedded dual optical resonator containing an optical parametric oscillator/laser crystal. The embedded dual optical resonator includes a laser resonator and an optical parametric oscillator resonator. The OPOL crystal is an optical parametric oscillator material doped with ions that exhibit lasing transitions. The pump radiation stimulates generation of laser radiation. When the laser radiation reaches the parametric threshold, optical parametric radiation is generated. In one embodiment, the laser resonator and the OPOL resonator are each defined by spaced-apart mirrors. In another embodiment, the OPOL system includes an OPOL rod having end caps at each end. Each end cap includes surfaces for internally reflecting the laser radiation and the parametric optical radiation in a closed loop path so that the OPOL rod and the end caps define an optical resonator.Type: GrantFiled: March 15, 1993Date of Patent: March 1, 1994Assignee: LaSen, Inc.Inventors: Allen R. Geiger, Narasimha S. Prasad
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Patent number: 5195104Abstract: An optical parametric oscillator/laser system includes an optical pump source for generating pump radiation and an embedded dual optical resonator containing an optical parametric oscillator/laser crystal. The embedded dual optical resonator includes a laser resonator and an optical parametric oscillator resonator. The OPOL crystal is an optical parametric oscillator material doped with ions that exhibit lasing transitions. The pump radiation stimulates generation of laser radiation. When the laser radiation reaches the parametric threshold, optical parametric radiation is generated. In one embodiment, the laser resonator and the OPOL resonator are each defined by spaced-apart mirrors. In another embodiment, the OPOL system includes an OPOL rod having end caps at each end. Each end cap includes surfaces for internally reflecting the laser radiation and the parametric optical radiation in a closed loop path so that the OPOL rod and the end caps define an optical resonator.Type: GrantFiled: October 15, 1991Date of Patent: March 16, 1993Assignee: Lasen, Inc.Inventors: Allen R. Geiger, Narasimha S. Prasad
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Patent number: 5159487Abstract: An optical parametric oscillator includes a pump laser for producing a pump beam, an optical resonator, an OPO crystal disposed within the optical resonator aligned with and responsive to the pump beam to produce a parametrically generated output, and a device external to the optical resonator for line narrowing the parametrically generated output. In one embodiment of the invention, the device is a grating and in another embodiment of the invention the device is an acousto-optic cell.Type: GrantFiled: May 29, 1991Date of Patent: October 27, 1992Assignee: LaSen, Inc.Inventors: Allen R. Geiger, Narasimha S. Prasad