Method for remotely measuring fluctuations in the optical index of refraction of a medium
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsLee E. Estes, Peter J. Hendricks, Adam Jilling
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Abstract
A method is provided for remotely measuring index of refraction fluctuations. From a first location, an optical beam is focused at a focal plane located at a second location in a medium of interest. As a result, a beam of energy is backscattered towards the first location. At the first location, a size of the backscattered beam is determined where the size is indicative of strength of fluctuations in the medium's index of refraction.
Claims15
A method of remotely measuring fluctuations in a medium's index of refraction, comprising the steps of:
- focusing, from a first location, a first beam of optical energy at a focal plane located at a second location in a medium of interest wherein a second beam of optical energy is backscattered towards said first location;
- receiving said second beam of optical energy at said first location;
- and
- determining a change in size of said second beam wherein said change is an indirect measurement of strength of fluctuations in the medium's index of refraction.
A system for remotely measuring fluctuations in a medium's index of refraction, comprising:
- a light source at a first location for focusing a first beam of optical energy at a focal plane located at a second location in a medium of interest wherein a second beam of optical energy is backscattered towards said first location;
- a detector at said first location for generating an image of said second beam at said first location;
- and
- a processor coupled to said detector for determining irradiance associated with said image, wherein said irradiance is indicative of size of said second beam, and wherein said size is indicative of strength of fluctuations in the medium's index of refraction.
A system for remotely measuring fluctuations in a medium's index of refraction, comprising:
- a laser capable of providing a light beam;
- a beam splitter having an input joined to receive the light beam from said laser, a port capable of providing output of a beam received at the input and further being capable of receiving a backscatter light beam, and an output capable of providing the backscatter light beam received at the port;
- a lens joined to said beam splitter port for focusing said beam splitter port output to a remote location located at a distance from said lens whereby said beam splitter port output causes creation of a backscatter light beam through interaction with the medium, said backscatter light beam returning through said lens to said beam splitter port, and the light beam being provided as a pulse of shorter length than the distance between said lens and the remote location;
- a detector joined to said beam splitter output for detecting a change in size of the backscatter light beam;
- and
- a processor joined to the detector and capable of providing a measure fluctuations in the medium's index of refraction.
Dependencies are inferred from the claim text.