Laser barometer
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsKevin R. Abercrombie, David Shiels, Tim Rash
Life of this patent
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Abstract
A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.
Claims6
A pressure measuring instrument comprising:
- a) a means for generating a laser beam;
- b) a photodetector for receiving a laser beam;
- c) a container capable of containing diverse atmospheric environments, said container comprising an optical window on a first end of said container, and a reflecting means located at a second end of said container,
- d) an interferometer for receiving said laser beam and splitting said laser beam into first and second components, directing said first component to said photodetector wherein said first component serves as a reference signal, and directing said second component to said container wherein said second component serves as a measuring signal, and wherein said second component enters said container through said optical window and is reflected by said reflecting means back through said container and said optical window to said interferometer where said second component is mixed with said first component and where said mixing of first and second components which are out-of-phase with respect to each other generates a series of fringes and where a shift in said series of fringes generated within said interferometer is detected by said photodetector;
- and where said photodetector outputs an electronic pulse;
- and
- e) a computer means coupled to said photodetector for determining the calibration of a pressure based on said first and second components prior to introducing gas into said container, and for determining said pressure within said container once gas is introduced into said container by converting said output electronic pulses into pressure units.
A pressure measuring instrument comprising:
- a) a means for generating a laser beam;
- b) a photodetector for receiving a laser beam;
- c) a tube capable of containing diverse atmospheric environments, said tube comprising an optical window on a first end of said tube, and a reflecting means located at a second end of said tube;
- d) an interferometer for receiving said laser beam and splitting said laser beam into first and second components, directing said first component to said photodetector wherein said first component serves as a reference signal, and directing said second component to said tube wherein said second component serves as a measuring signal, and wherein said second component enters said tube through said optical window and is reflected by said reflecting means back through said tube and said optical window to said interferometer where said second component is mixed with said first component and where said mixing of first and second components which are out-of-phase with respect to each other generates a series of fringes and where a shift in said series of fringes generated within said interferometer is detected by said photodetector;
- and where said photodetector outputs an electronic pulse;
- and
- e) a computer means coupled to said photodetector for determining the calibration of a pressure based on said first and second components prior to introducing gas into said tube, and for determining said pressure within said tube once gas is introduced into said tube by converting said output electronic pulses into pressure units.
Dependencies are inferred from the claim text.