Patents by Inventor Upendra N. Singh

Upendra N. Singh 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).

  • Patent number: 12040586
    Abstract: A dynamic, thermally-adaptive cuboid laser crystal mount is provided that is suitable for use with end-pumped, conductively-cooled solid state lasers. Various embodiments may provide a mount for supporting a cuboid rod host crystal for an end-pumping solid state laser. Various embodiments may solve laser crystal stress problems typically experienced in end-pumped solid state lasers. Various embodiments may also provide access to the crystal end surfaces for pumping and enable and maintain sturdy alignment of the crystal with continuous and uniform surface contact between the mount and the crystal. Various embodiments of mounts may provide a compact conductive cooling configuration compatible with any heat sink reservoir, controlling and maintaining a stable crystal temperature, thus avoiding thermally induced mechanical stresses. Various embodiment mounts may thereby further extend the fracture threshold of the laser crystal.
    Type: Grant
    Filed: February 19, 2020
    Date of Patent: July 16, 2024
    Assignee: UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA
    Inventors: Tamer F. Refaat, Mulugeta Petros, Upendra N. Singh
  • Patent number: 11340337
    Abstract: A laser transmitter assembly for use in a Coherent Doppler Wind Lidar (“CDWL”) system includes a telescope/scanner assembly, a receiver, and a master oscillator crystal and a power amplifier crystal each constructed of Ho:YAG. The crystals are end-pumped to transmit an output beam through the telescope/scanner assembly with a high repetition rate of 200-300 Hz and 35 mJ of energy. As part of the CDWL system, a pump laser end-pumps the master oscillator and power amplifier crystals using a pump beam having a nominal wavelength of 1.905 ?m. A seed laser transmits a seeding beam into the master oscillator crystal at a nominal wavelength of 2.0965 ?m. The telescope/scanner assembly transmits the generated laser beam through an atmosphere toward a scene of interest, collects a backscattered return signal, and communicates the backscattered return signal to the receiver during operation of the CDWL system.
    Type: Grant
    Filed: December 17, 2019
    Date of Patent: May 24, 2022
    Assignee: UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA.
    Inventors: Upendra N Singh, Mulugeta Petros, Tamer F. Refaat
  • Patent number: 11251582
    Abstract: Aspects of the present disclosure are directed to methods and apparatuses for generating laser light. As may be implemented in accordance with one or more embodiments, laser light is generated at a laser light source and is modulated in response to a frequency modulation signal, to generate a plurality of different wavelengths of laser light. The frequency modulation signal is generated, for each particular one of the wavelengths of laser light, at a respective seeding frequency corresponding to the particular one of the wavelengths in which the seeding frequency is different for each of the different wavelengths. Such an approach may, for example, involve generating the frequency modulation signal with a frequency generator circuit and using the frequency modulation signal to control an electro-optical modulator for modulating the wavelength of the laser light.
    Type: Grant
    Filed: February 20, 2019
    Date of Patent: February 15, 2022
    Assignee: UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA
    Inventors: Mulugeta Petros, Tamer Refaat, Upendra N. Singh, Charles W. Antill
  • Patent number: 10996102
    Abstract: Systems, methods, and devices of the various embodiments may provide a fast and precise methods for continuously monitoring and measuring the absolute wavelength of monochromatic radiation sources, such as lasers, etc., irrespective of the temporal profile of the source (i.e., continuous wave, modulated, or pulsed). Radiation power measurement may also be enabled by the various embodiment methods. The various embodiment methods may utilize high-speed low-noise detection to enable fast and accurate measurements. High-precision wavelength and power measurement may be achieved in the various embodiments to monitor radiation source jitters and fluctuations, without relying on frequency transforms or dispersive optics. Both wavelength and power may be measured simultaneously or sequentially in various embodiments.
    Type: Grant
    Filed: May 17, 2018
    Date of Patent: May 4, 2021
    Assignee: UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA
    Inventors: Tamer Refaat, Mulugeta Petros, Upendra N. Singh
  • Publication number: 20200266599
    Abstract: A dynamic, thermally-adaptive cuboid laser crystal mount is provided that is suitable for use with end-pumped, conductively-cooled solid state lasers. Various embodiments may provide a mount for supporting a cuboid rod host crystal for an end-pumping solid state laser. Various embodiments may solve laser crystal stress problems typically experienced in end-pumped solid state lasers. Various embodiments may also provide access to the crystal end surfaces for pumping and enable and maintain sturdy alignment of the crystal with continuous and uniform surface contact between the mount and the crystal. Various embodiments of mounts may provide a compact conductive cooling configuration compatible with any heat sink reservoir, controlling and maintaining a stable crystal temperature, thus avoiding thermally induced mechanical stresses. Various embodiment mounts may thereby further extend the fracture threshold of the laser crystal.
    Type: Application
    Filed: February 19, 2020
    Publication date: August 20, 2020
    Inventors: Tamer F. Refaat, Mulugeta Petros, Upendra N. Singh
  • Publication number: 20200200876
    Abstract: A laser transmitter assembly for use in a Coherent Doppler Wind Lidar (“CDWL”) system includes a telescope/scanner assembly, a receiver, and a master oscillator crystal and a power amplifier crystal each constructed of Ho:YAG. The crystals are end-pumped to transmit an output beam through the telescope/scanner assembly with a high repetition rate of 200-300 Hz and 35 mJ of energy. As part of the CDWL system, a pump laser end-pumps the master oscillator and power amplifier crystals using a pump beam having a nominal wavelength of 1.905 ?m. A seed laser transmits a seeding beam into the master oscillator crystal at a nominal wavelength of 2.0965 ?m. The telescope/scanner assembly transmits the generated laser beam through an atmosphere toward a scene of interest, collects a backscattered return signal, and communicates the backscattered return signal to the receiver during operation of the CDWL system.
    Type: Application
    Filed: December 17, 2019
    Publication date: June 25, 2020
    Inventors: Upendra N. Singh, Mulugeta Petros, Tamer F. Refaat
  • Publication number: 20190353516
    Abstract: Systems, methods, and devices of the various embodiments may provide a fast and precise methods for continuously monitoring and measuring the absolute wavelength of monochromatic radiation sources, such as lasers, etc., irrespective of the temporal profile of the source (i.e., continuous wave, modulated, or pulsed). Radiation power measurement may also be enabled by the various embodiment methods. The various embodiment methods may utilize high-speed low-noise detection to enable fast and accurate measurements. High-precision wavelength and power measurement may be achieved in the various embodiments to monitor radiation source jitters and fluctuations, without relying on frequency transforms or dispersive optics. Both wavelength and power may be measured simultaneously or sequentially in various embodiments.
    Type: Application
    Filed: May 17, 2018
    Publication date: November 21, 2019
    Inventors: Tamer Refaat, Mulugeta Petros, Upendra N. Singh
  • Publication number: 20190260177
    Abstract: Aspects of the present disclosure are directed to methods and apparatuses for generating laser light. As may be implemented in accordance with one or more embodiments, laser light is generated at a laser light source and is modulated in response to a frequency modulation signal, to generate a plurality of different wavelengths of laser light. The frequency modulation signal is generated, for each particular one of the wavelengths of laser light, at a respective seeding frequency corresponding to the particular one of the wavelengths in which the seeding frequency is different for each of the different wavelengths. Such an approach may, for example, involve generating the frequency modulation signal with a frequency generator circuit and using the frequency modulation signal to control an electro-optical modulator for modulating the wavelength of the laser light.
    Type: Application
    Filed: February 20, 2019
    Publication date: August 22, 2019
    Inventors: MULUGETA PETROS, TAMER REFAAT, UPENDRA N. SINGH, CHARLES W. ANTILL