Optical Interrogator for Rapid Polarization Characterization
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Solution Overview
Problem
Existing methods for characterizing an object's polarization properties are time-consuming, especially in dynamic environments, require sequential measurements, assume object stability, need calibration for each polarization source, and involve absolute measurement of optical power.
Innovation Solution
An optical interrogator system that splits a laser pulse into segments with different polarizations (0°, 45°, 90°, 135° linear, and circular) and recombines them into a train of co-aligned pulses for rapid illumination of an object, allowing for quick determination of polarization characteristics using a receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential measurements are used to measure reflected Stokes parameters for different generated Stokes parameters, then measurement completeness is achieved, but measurement time becomes excessively long
Solution Approach 1:
The invention segments a single laser pulse into multiple time-delayed segments (first through sixth segments) with different polarizations. Each segment is polarized independently to provide a different generated Stokes parameter, allowing all necessary polarization states to be obtained from one pulse rather than requiring sequential measurements over time.
Solution Approach 2:
The invention uses periodic modulation of polarization states within a single pulse train. By introducing time delays and applying different polarization transformations to successive segments, the system creates a periodic sequence of polarization states that enables complete Mueller matrix characterization without temporal sequencing of separate measurements.
2Measurement precision
If sequential measurements are performed in dynamic environments, then complete polarization data can be collected, but the medium conditions change during measurement causing measurement errors
Solution Approach 1:
By segmenting a single laser pulse into multiple polarization states that are transmitted through the medium simultaneously or near-simultaneously, the invention ensures that all measurements experience essentially the same medium conditions. This eliminates the problem of medium changes between sequential measurements while maintaining complete polarization data collection.
3Ease of operation
If sequential measurements are used assuming object stability, then measurement simplicity is maintained, but the method fails for moving objects where pose changes occur
Solution Approach 1:
The invention segments a single laser pulse into multiple polarization components that illuminate the object simultaneously. This allows measurement of complete polarization characteristics even when the object moves or changes pose during the measurement, as all polarization states are captured in essentially the same temporal window.
4Measurement precision
If calibration is performed for each polarization source, then measurement accuracy is ensured, but device complexity and calibration time increase
Solution Approach 1:
The invention merges multiple polarization measurements into a single pulse transmission event. By using a single laser source and splitting it into multiple polarization segments, the system requires calibration of only one source rather than multiple independent polarization sources, significantly reducing calibration complexity while maintaining measurement accuracy.
5Measurement precision
If absolute measurement is performed for each interrogating polarization source, then complete polarization characterization is achieved, but measurement time and complexity increase
Solution Approach 1:
The invention combines multiple polarization measurements into a single integrated measurement process. By using a single laser source that is split into multiple polarization segments, the system performs all necessary optical power measurements simultaneously rather than sequentially for each polarization source, reducing both time and complexity.
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
Enables rapid characterization of an object's polarization properties in nanoseconds, suitable for moving objects and dynamic environments, with simplified calibration and reduced measurement time, as the system can sample objects nearly instantaneously and account for medium changes.
Implementation Method 1
The optical polarizing element is positioned so as to respectively polarize the first, second, third, fourth, fifth, and sixth laser segments with a 0° linear polarization, a 45° linear polarization, a 90° linear polarization, a 135° linear polarization
Implementation Method 2
a right-handed, circular polarization (RHCP), and a left-handed, circular polarization (LHCP)
Data Source
AI summary
An optical interrogator for illuminating an object comprising a laser, a splitter, an optical polarizing element, and an optical recombiner. The laser is configured to generate a laser pulse, which the splitter splits into first, second, third, fourth, fifth, and sixth laser segments such that each of the laser segments are separated by a time delay on the order of nanoseconds between each laser segment. The optical polarizing element is positioned so as to respectively polarize the first, second, third, fourth, fifth, and sixth laser segments with a 0° linear polarization, a 45° linear polarization, a 90° linear polarization, a 135° linear polarization, a right-handed, circular polarization (RHCP), and a left-handed, circular polarization (LHCP). The optical recombiner combines the polarized laser segments into a train of co-aligned pulses for illuminating the object.