Holographic laser aimpoint selection and maintenance
First Claim
1. A laser target acquisition and tracking system with small-spot aimpoint selection and maintenance and compensation for optical distortion comprising:
- a) an illuminate laser frequency-locked to a laser master oscillator for directing a first wide-divergence beam of radiation through media toward a target wherein said target reflects a portion of said radiation as a beam or diffuse return;
b) a high speed detector for receiving a portion of said return;
c) a laser local oscillator frequency-locked to said master oscillator and triggered by said detector for generating a short-pulse reference beam where said pulsed reference beam has a variable delay with respect to the leading edge of said return;
d) an electronic radiation detector array for receiving the interference of a portion of said return and said pulsed reference beam for providing detector array signals containing information about said media and a slice of said target selected by the delay and pulse length of said reference beam;
e) a hologram processor responsive to said electronic signals from said radiation detector array to form an electronic hologram pattern;
f) a spatial light modulator responsive to said electronic hologram pattern wherein said spatial light modulator records said hologram as a binary phase pattern; and
g) a laser for directing a beam of radiation onto said spatial light modulator for providing a phase-conjugate beam being directed to a selected part of said target.
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Accused Products
Abstract
The present invention relates to a laser pointing and tracking system which forms and maintains a small laser spot size at a selected aimpoint on a target and compensates for optical distortion in the intervening media. The invention comprises an illumination laser for directing a first wide divergence beam of short-pulse laser radiation toward a stationary or moving target. The target reflects a portion of the incident beam as return radiation which is interfered with a properly-timed short-pulse reference beam on an electronic radiation detector array. The detector array signals are processed to produce an electronic hologram which is imposed as a phase pattern on a spatial light modulator. A laser reads out the hologram to direct a beam of radiation at the target. Multiple sequential illumination and hologram formation/readout steps produce a small spot size at the selected aimpoint. The small spot is maintained at the aimpoint during the duration of an engagement by repeating the above steps.
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Citations
12 Claims
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1. A laser target acquisition and tracking system with small-spot aimpoint selection and maintenance and compensation for optical distortion comprising:
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a) an illuminate laser frequency-locked to a laser master oscillator for directing a first wide-divergence beam of radiation through media toward a target wherein said target reflects a portion of said radiation as a beam or diffuse return; b) a high speed detector for receiving a portion of said return; c) a laser local oscillator frequency-locked to said master oscillator and triggered by said detector for generating a short-pulse reference beam where said pulsed reference beam has a variable delay with respect to the leading edge of said return; d) an electronic radiation detector array for receiving the interference of a portion of said return and said pulsed reference beam for providing detector array signals containing information about said media and a slice of said target selected by the delay and pulse length of said reference beam; e) a hologram processor responsive to said electronic signals from said radiation detector array to form an electronic hologram pattern; f) a spatial light modulator responsive to said electronic hologram pattern wherein said spatial light modulator records said hologram as a binary phase pattern; and g) a laser for directing a beam of radiation onto said spatial light modulator for providing a phase-conjugate beam being directed to a selected part of said target. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for forming a small laser spot at an aimpoint on a target and with compensation for optical distortion by intervening media comprising the steps of:
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a) illuminating a target with a short pulse of laser radiation; b) detecting at a receiver a reflected radiation return from said target; c) generating a short-pulse reference beam triggered by and delayed with respect to said radiation return; d) interfering said target return with said pulsed reference beam on a two-dimensional detector array to thereby produce a hologram that is stored as an array of electronic signals; e) transferring said array of signals through a real-time electronic processor to produce a hologram pattern containing information about the part of the target selected by the pulsed reference beam and about the media between the target and the detector array; f) thereafter imposing said processed array of electronic voltages on a spatial light modulator; and g) reading out the hologram on said spatial light modulator by interacting a second laser beam with said hologram on said spatial light modulator to direct a conjugate beam of focused laser radiation compensated for the effects of media distortion to the selected part of said target. - View Dependent Claims (9, 10, 11, 12)
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Specification