Optical Pointing System Phase Conjugation Moving Target

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Solution Overview

Problem

Current laser pointing systems face challenges in accurately directing a laser beam to a moving object, such as a car, for applications like cutting or drilling, due to issues with low returned power, high Doppler frequency shift, and large temporal delays, especially when submicroradian accuracies are required.

Innovation Solution

A method involving a pulsed laser beam transmission, selective phase conjugation, and amplification to generate an amplified phase conjugated beam, which is then angularly shifted to precisely target a selected area on a moving object, using a system with an optical transmitter module, receiver module, and phase conjugation mirror, allowing for accurate interaction like cutting, drilling, or welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional laser pointing techniques are used to track moving objects, then the system can maintain basic functionality, but the pointing accuracy deteriorates due to Doppler frequency shift and temporal delays

Engineering Contradiction:
Improvepointing accuracyVSAvoidbeam tracking reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies phase conjugation to reverse the phase distortions caused by Doppler frequency shift and temporal delays. By conjugating the phase of the reflected beam and retransmitting it, the system compensates for the accumulated phase errors, thereby maintaining pointing accuracy despite the moving target's velocity and position changes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses the reflected beam from the moving object as feedback to determine the object's position and velocity. This feedback information is then used to adjust the beam direction in real-time, ensuring continuous accurate tracking of the moving target.

Inventive Principle:
Principle #23Feedback

2Productivity

If the laser beam is directed at a moving object, then the interaction (cutting, drilling) can be performed, but the returned power decreases due to the object's motion

Engineering Contradiction:
Improveinteraction effectivenessVSAvoidreturned power
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system performs preliminary phase conjugation based on the predicted position of the moving object. By pre-compensating for the expected phase distortions and beam wander caused by the object's motion, the system ensures that the beam remains focused on the target despite the reduced returned power signal.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If remote laser pointing is used for cutting or drilling, then the precision of the interaction is improved, but the system complexity increases due to the need for high accuracy tracking

Engineering Contradiction:
Improvecutting/drilling precisionVSAvoidtracking system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces phase conjugation as an intermediary process between the transmitted beam and the moving target. This intermediary technique simplifies the tracking system by using the target's own reflected beam as the reference for phase conjugation, eliminating the need for complex external tracking sensors and reducing overall system complexity while maintaining high precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables precise and accurate laser beam targeting on moving objects, overcoming previous limitations by achieving high spatial resolution and maintaining orientation during translation or rotation, ensuring effective interactions like cutting or drilling with high precision.

Implementation Method 1

transmitting from a laser assembly that includes an optical transmitter module a pulsed laser beam

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

obtaining a reflected pulsed laser beam

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

receiving, in a second laser assembly that includes the optical receiver module, the reflected pulsed laser beam

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Implementation Method 4

performing selective phase conjugation, thereby generating an amplified phase conjugated pulsed beam

Methodology Applied
Scientific EffectPhase conjugation:

Implementation Method 5

generating an amplified phase conjugated pulsed beam

Methodology Applied
Scientific EffectOptical amplification:

Data Source

PatentEP2912519B1Optical pointing system
Publication Date: 2023.08.02 ISRAEL AEROSPACE IND LTD
  • EP2912519B1 patent drawingFigure 1
  • EP2912519B1 patent drawingFigure 2
  • EP2912519B1 patent drawingFigure 3A~3C

AI summary

A method for directing a laser pulsed beam towards a selected area/surface of an object, comprising transmitting from a laser assembly that includes an optical transmitter module a pulsed laser beam having a first pulse duration and illuminating therewith an area/surface of the object, thereby obtaining a reflected pulsed laser beam, the reflected pulsed laser beam including a leading portion reflected from a first reflecting area/surface of the object which is the area of the object that defines the shortest optical path between the optical transmitter module, the object and an optical receiver module; receiving, in a second laser assembly that includes the optical receiver module, the reflected pulsed laser beam and converting it into an amplified phase conjugated pulsed beam of a second pulse duration, and transmitting from the second laser assembly the amplified phase conjugated pulsed beam and illuminating therewith on selected area/surface of the object.