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US 10,295,673 B1Granted
Nested interferometer for optical autocovariance lidar
AssigneeBall Aerospace & Technologies Corp.
InventorSara C. Tucker
Life of this patent
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Abstract
Lidar systems and methods are provided. The lidar system includes a laser that outputs light at two different wavelengths and an interferometer that is capable of generating fringe patterns for each of the two wavelengths simultaneously. More particularly, a first arm of the interferometer provides first and second path lengths. Light of a first of two or more wavelengths traverses the first path length within the first arm, while light of a second one of the two wavelengths traverses the second path length within the first arm. A second arm of the interferometer provides a third path length. Light from the first and second arms is then combined, and a phase shift of light of the first wavelength and a phase shift of light of the second wavelength are determined.
Claims20
An interferometer, comprising:
- a first non-polarizing dual-wavelength beam splitter;
- a first arm, wherein the first arm provides an optical path for light that is a first one of reflected or transmitted by the first non-polarizing beam splitter, the first arm including:
- a first reflective element, wherein the first reflective element of the first arm reflects light of a first wavelength and transmits light of a second wavelength, and wherein the first reflective element of the first arm is a first distance from the first non-polarizing beam splitter;
- and
- a second reflective element, wherein the second reflective element of the first arm reflects light of the second wavelength, wherein the second reflective element of the first arm is a second distance from the first non-polarizing beam splitter, and wherein the second distance is greater than the first distance;
- a second arm, wherein the second arm provides an optical path for light that is a second one of reflected or transmitted by the first non-polarizing beam splitter, the second arm including:
- a first reflective element, wherein the first reflective element of the second arm is a third distance from the first non-polarizing beam splitter, and wherein the third distance is different than the first and second distances;
- a dual-wavelength quarter wave plate, wherein the quarter wave plate is located along the optical path of one of the first arm and the second arm;
- and
- a second non-polarizing dual-wavelength beam splitter, wherein the second non-polarizing beam splitter receives light reflected from the first and second reflective elements of the first arm and from the first reflective element of the second arm.
7 more elements
A system, comprising:
- a light source, wherein the light source outputs light having a first wavelength and light having a second wavelength;
- a telescope;
- an interferometer, including:
- a first non-polarizing beam splitter, wherein the first non-polarizing beam splitter receives light from the telescope;
- a first arm, wherein the first arm receives light that is a first one of reflected or transmitted by the first beam splitter, wherein the first arm provides a first optical path length for light having the first wavelength, and wherein the first arm provides a second optical path length for light having the second wavelength;
- a second arm, wherein the second arm receives light that is a second one of reflected or transmitted by the first beam splitter, and wherein the second arm provides a third optical path length;
- a second non-polarizing beam splitter, wherein light from the first and second arms are incident on the second beam splitter and form interference patterns, wherein a first portion of the incident light is passed to a first dichroic followed by two polarizing beam splitters, and wherein a second portion of the incident light is passed to a second dichroic followed by two polarizing beam splitters;
- and
- a plurality of detectors, wherein a first one of the detectors receives a component of light that is separated in phase from light received by a second one of the detectors.
6 more elements
A method for measuring atmospheric winds, comprising:
- reflecting light of first and second wavelengths from a target volume;
- receiving the reflected light;
- delaying a portion of the received light of the first wavelength by a first amount;
- delaying a portion of the received light of the second wavelength by a second amount;
- delaying another portion of the received light of the first wavelength by a third amount;
- delaying another portion of the received light of the second wavelength by the third amount;
- mixing the portion of the received light delayed by the first amount with some of the portion of the received light delayed by the third amount and detecting an amplitude of the mixed light at three or more intervals;
- and
- mixing the portion of the received light delayed by the second amount with some of the portion of the received light delayed by the third amount and detecting an amplitude of the mixed light at three or more intervals.
6 more elements
Dependencies are inferred from the claim text.