Laser microphone
AssigneesBrookhaven Science Associates, LLC, Brookhaven National Laboratory
InventorJames T. Veligdan
Life of this patent
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Abstract
A microphone for detecting sound pressure waves includes a laser resonator having a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam. A reference cell is disposed between the laser material and one of the mirrors for transmitting a reference portion of the laser beam between the mirrors. A sensing cell is disposed between the laser material and one of the mirrors, and is laterally displaced from the reference cell for transmitting a signal portion of the laser beam, with the sensing cell being open for receiving the sound waves. A photodetector is disposed in optical communication with the first mirror for receiving the laser beam, and produces an acoustic signal therefrom for the sound waves.
Claims12
A microphone for detecting sound pressure waves comprising:
- a laser resonator including a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam;
- a reference cell disposed between said laser material and one of said mirrors for transmitting a reference portion of said laser beam between said mirrors;
- a sensing cell disposed between said laser material and one of said mirrors, and laterally displaced from said reference cell for transmitting a signal portion of said laser beam, with said sensing cell being open for receiving said sound waves;
- and
- a photodetector disposed in optical communication with one of said mirrors for receiving said laser beam including both said reference and signal portions and producing an acoustic signal therefrom for said sound waves.
A method of optically detecting sound pressure waves without a moving mass diaphragm comprising:
- optically pumping a laser gain material in a laser resonator to produce a laser beam;
- modulating in said laser resonator a first portion of said laser beam with said sound waves;
- and
- heterodyning a second portion of said laser beam with said modulated first portion to produce an acoustic signal for said sound waves.
Dependencies are inferred from the claim text.