Active imaging system that recaptures and processes a reflected illumination beam
AssigneeNorthrop Grumman Space & Mission Systems Corp.
InventorBo Su Chen
Life of this patent
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Abstract
In accordance with yet another aspect of the present invention, an active imaging system is provided for imaging a target of interest. An imaging assembly includes a light source and an optical assembly comprising a plurality of passive optical components. The optical assembly divides received light into a first beam, having a first polarization and a second beam, having a second, orthogonal polarization, directs the first and second beam along respective first and second optical paths within the optical assembly, and recombines the first and second beams into a combined beam. A sensor detects the combined beam.
Claims14
An apparatus for detecting a beam of light reflected from a region of interest, comprising:
- a light source that produces a light beam having a first polarization state;
- a first polarization beam splitter that directs the light beam along a first optical path, and allows light having a second polarization state, orthogonal to the first polarization state, to pass;
- an optical polarization modulator, located along the first optical path, that applies a net rotation of ninety degrees to the polarization of light passing through the optical polarization modulator in a first direction and applies a net rotation of zero degrees to the polarization of light passing through the optical polarization modulator in a second direction, the first polarization beam splitter directing the light beam through the optical polarization modulator to the region of interest;
- a second polarization beam splitter, positioned along the first optical path such that the optical polarization modulator is between the first polarization beam splitter and the second polarization beam splitter, that allows a first portion of the beam of light that is reflected from the region of interest having the second polarization state to pass to the optical polarization modulator and directs a second portion of the beam of light that is reflected from the region of interest having the first polarization state along a second optical path;
- and
- a third polarization beam splitter configured to allow light having the second polarization state to pass and reflect light having the first polarization state, the third polarization beam splitter being positioned as to combine light from the first optical path and light from the second optical path and direct the combined light onto a sensor.
An active imaging system for imaging a target of interest, comprising:
- a light source that generates a light beam that illuminates the target of interest;
- an optical assembly comprising:
- a first beam splitter that divides light reflected from the target of interest into a first beam having a first polarization and which is directed along a first optical path from the first beam splitter and a second beam having a second polarization that is orthogonal to the first polarization and is directed along a second optical path from the first beam splitter;
- a second beam splitter that recombines the first and second beams into a combined beam;
- a third beam splitter that directs the light beam having the first polarization along the first optical path and allows light having the second polarization to pass;
- and
- an optical polarization modulator, located along the first optical path, that applies a net rotation of zero degrees to the polarization of light passing through the optical polarization modulator in a first direction and applies a net rotation of ninety degrees to the polarization of light passing through the optical polarization modulator in a second direction as to convert light passing through the optical polarization modulator in the second direction from the first polarization to the second polarization, the third beam splitter directing the light beam onto the optical polarization modulator;
- wherein the first beam splitter is positioned along the first optical path such that the optical polarization modulator is between the first beam splitter and the third beam splitter and allows the first beam to pass to the optical polarization modulator and directs the second beam along the second optical path;
- and
- a sensor that detects the combined beam.
Dependencies are inferred from the claim text.