Phase-Conjugate Laser Tracking for High-Energy Moving Targets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical pointing and tracking systems face limitations in directing high-energy laser beams towards targets, especially moving targets, due to damage risks to system components and constraints imposed by the time of flight for laser-target interaction.
Innovation Solution
A system comprising a probe laser device, an optical subsystem with a reorientation module including a film polarizer, a medium, and a phase conjugate mirror, and a pump laser device that generates a sequence of pump laser pulses to create a Brillouin grating, allowing for the generation of reoriented pump laser pulses that can illuminate the target efficiently while preventing damage to system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high laser power is used to achieve high energy and high-power densities for cutting or welding, then the energy delivery capability is improved, but the risk of damage to optical and laser system components increases
Solution Approach 1:
The pump laser pulses are divided into a sequence of multiple lower-power pulses rather than using a single high-power pulse. This segmentation allows the system to deliver cumulative energy to the target while keeping individual pulse powers below the damage threshold of optical components.
Solution Approach 2:
The system uses periodic pumping with a sequence of pump laser pulses separated by time intervals. This periodic action allows the Brillouin grating to be continuously sustained and refreshed, enabling cumulative energy delivery while maintaining safe power levels during each individual pulse.
2Length of stationary object
If the repetition period is increased to allow for time of flight to moving targets, then the range capability is improved, but the tracking speed and response time deteriorate
Solution Approach 1:
The Brillouin grating is prepared and sustained in advance within the medium before the probe pulse arrives at the target. This preliminary action allows the system to have the redirecting mechanism ready, eliminating the need to wait for the round-trip time of the probe pulse before initiating the high-power delivery sequence.
Solution Approach 2:
The patent introduces a medium (such as a gas or liquid) as an intermediary that can sustain the Brillouin grating for extended periods. This intermediary allows the system to maintain the redirecting mechanism over longer time intervals, enabling tracking of distant moving targets without sacrificing tracking speed.
3Use of energy by moving object
If a sequence of pump laser pulses is used to create and sustain the Brillouin grating, then the energy delivery is improved, but the system complexity increases
Solution Approach 1:
The medium itself provides the mechanism for grating creation and sustenance through the Brillouin scattering effect. The sequence of pump pulses automatically interacts with the probe pulse to create and refresh the grating without requiring external control mechanisms, reducing system complexity while maintaining energy delivery capability.
4Reliability
If the optical subsystem maintains a fixed orientation, then the system reliability is improved, but the ability to track moving targets deteriorates
Solution Approach 1:
The patent uses the medium and Brillouin grating as an intermediary that performs the tracking function. The fixed optical subsystem creates the grating in the medium, and the grating itself adapts to redirect pulses toward moving targets, allowing the optical subsystem to remain fixed while maintaining tracking capability.
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
The system enables efficient and accurate tracking of moving targets with high-energy interactions while preventing damage to optical and laser system components, allowing for a fixed orientation of the optical subsystem to illuminate multiple targets without modification.
Implementation Method 1
the reorientation module is operative to use the phase conjugate mirror to generate a phase conjugated reflected probe pulse, which is phase conjugated with the reflected probe pulse
Implementation Method 2
receive, by the medium, the phase conjugated reflected probe pulse, and sequentially, a plurality of pump laser pulses of the sequence of pump laser pulses, thereby generating, in the medium, a grating
Implementation Method 3
the reorientation module comprises a film polarizer
Implementation Method 4
each given reoriented pump laser pulse of the plurality of reoriented pump laser pulses exits the film polarizer of the reorientation module along a path coinciding with the reflected probe path
Data Source
AI summary
A system comprises a probe laser device configured to transmit a probe pulse towards an object, thereby obtaining a reflected probe pulse, a reorientation module including a film polarizer, a medium and a phase conjugate mirror, wherein a path of the reflected probe pulse from its reflection to the film polarizer is designated as a reflected probe path, wherein the reorientation module is operative to use the phase conjugate mirror to generate a phase conjugated reflected probe pulse, which is phase conjugated with the reflected probe pulse, receive, by the medium, the phase conjugated reflected probe pulse, and sequentially, a plurality of pump laser pulses, thereby generating, in the medium, a grating, reflect, using the grating, the plurality of pump laser pulses as a plurality of reoriented pump laser pulses each exiting the film polarizer along a path coinciding with the reflected probe path, to illuminate the object.