Compact and highly sensitive gravity gradiometer
AssigneeSRI International
InventorsJesse Wodin, Sunil Goda, Eric Lavelle, Jan van der Laan, Ronald Pelrine, David Watt
Life of this patent
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Abstract
Example gravity gradiometers are described that utilize high precision resonant optical cavities to measure changes in gravitational forces at high sensitivities. In one example, a sensing system includes a gravity gradiometer and a controller. The gravity gradiometer includes a first mirror and a second mirror arranged to form an optical cavity having an optical axis. The controller is configured to detect, responsive to displacement of at least one of the first mirror and the second mirror along the optical axis, a change in gravity gradient.
Claims20
A gravity gradiometer, comprising:
- a first mirror and a second mirror arranged to form an optical cavity having an optical axis;
- and
- a drive and bearing system configured to displace at least one of the first and second mirrors along the optical axis in response to a change in gravity gradient,
- wherein the optical cavity is configured to reflect an optical signal at off-resonant wavelengths in response to displacement of the at least one of the first and second mirrors along the optical axis, and
- wherein the drive and bearing system is configured to differentially move the first and second mirrors along the optical axis, in response to electrical currents based on the reflected optical signal at the off-resonant wavelengths, to attempt to continuously maintain a specified length of the optical cavity.
A sensing system, comprising:
- a gravity gradiometer comprising a first mirror and a second mirror arranged to form an optical cavity having an optical axis;
- and
- a controller configured to detect, responsive to displacement of at least one of the first mirror and the second mirror along the optical axis, a change in gravity gradient,
- wherein the optical cavity is configured to reflect an optical signal at off-resonant wavelengths in response to displacement of the at least one of the first and second mirrors along the optical axis, and
- wherein the gravity gradiometer is configured to differentially move the first and second mirrors along the optical axis, in response to electrical currents based on the reflected optical signal at the off-resonant wavelengths, to attempt to continuously maintain a specified length of the optical cavity.
A method, comprising:
- reflecting, responsive to displacement of a first mirror with respect to a second mirror of an optical cavity along an optical axis, an optical signal at off-resonant wavelengths to detect a change in gravity gradient;
- differentially moving the first and second mirrors along the optical axis, in response to electrical currents based on the reflected optical signal at the off-resonant wavelengths, to attempt to continuously maintain a specified length of the optical cavity;
- and
- outputting an indication of the detected change in gravity gradient.
Dependencies are inferred from the claim text.