Multispectral Wavefront Sensor Using Optical Mask
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Solution Overview
Problem
Current wavefront sensors can only measure a single intensity pattern and wavefront per image acquisition, making it impossible to simultaneously reconstruct wavefronts of light beams from different sources with varying wavelengths, especially in applications involving broad spectral widths and low repetition rate lasers.
Innovation Solution
A method using a single-shot multispectral wavefront measurement technique with an optical assembly comprising an optical mask and a matrix imaging sensor, generating uncorrelated intensity patterns for multiple wavelengths, allowing for simultaneous wavefront shape determination from a single signal image acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sequential measurements with bandpass filters are used to measure multiple spectral channels, then wavefront measurement capability is improved, but device complexity increases and measurement time increases
Solution Approach 1:
The patent segments the spectral measurement process by using a single shot intensity pattern that contains information from all spectral channels simultaneously. The segmentation is achieved in the computational domain where the intensity pattern is decomposed into contributions from different wavelengths through optimization algorithms, rather than using physical segmentation with multiple filters.
Solution Approach 2:
The patent transitions from temporal sequential measurement to spatial simultaneous measurement by capturing all spectral information in a single intensity pattern on the detector. This dimensionality change allows all wavelength information to be encoded in the spatial distribution of intensities, which is then decoded through computational optimization.
2Adaptability or versatility
If sequential measurements with bandpass filters are used to measure multiple spectral channels, then wavefront measurement capability is improved, but measurement time increases
Solution Approach 1:
The patent performs preliminary encoding of all spectral information into a single intensity pattern that captures the combined effect of all wavelengths simultaneously. This preliminary action eliminates the need for sequential filtering and allows all wavefront measurements to be extracted from one captured pattern through computational decomposition.
Solution Approach 2:
The patent enables continuous simultaneous measurement of all spectral channels in a single shot, maintaining continuous useful action across all wavelengths at once. This eliminates the intermittent sequential nature of filtered measurements where only one wavelength is measured at a time, resulting in significant time savings.
3Measurement precision
If multiple bandpass filters are used to measure different wavelengths, then spectral resolution is improved, but cost increases
Solution Approach 1:
The patent replaces the mechanical/optical system of multiple physical bandpass filters with a computational algorithm that processes the intensity pattern. This substitution eliminates the need for expensive, precision-filter hardware while achieving equivalent or superior spectral discrimination through mathematical decomposition of the intensity distribution.
Solution Approach 2:
The patent creates computational copies of the spectral information contained in the single intensity pattern, extracting multiple wavefront profiles corresponding to different wavelengths from one measurement. This virtual copying approach replaces the need for physical filter copies and reduces hardware costs significantly.
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 simultaneous measurement of wavefront shapes at different wavelengths, reducing complexity and cost, and facilitating applications in optical metrology, laser metrology, and microscopy by avoiding the need for multiple filters and sequential measurements.
Implementation Method 1
The mask is used to create an intensity pattern on the camera... The intensity pattern changes due to the wavefront change... because of the mask that is placed before the intensity detector
Implementation Method 2
The optical mask having the optical properties: to produce uncorrelated intensity patterns over at least one surface area A of the imaging sensor, for a plurality of respective incident monochromatic beams of different wavelengths
Data Source
AI summary
A method for determining wavefront shapes of a multi-spectral signal light beam from a single signal image acquisition of said multi-spectral signal beam, with a device including an optical assembly made at least of an optical mask and an imaging sensor, notably a matrix imaging sensor, for generating and recording intensity patterns of incident beams, by having these beams reflect on, or propagate through, the optical mask. The optical mask having the optical properties: i) to cause the intensity pattern to depend on the wavefront shape, so that a tilt applied to the wavefront shape results in a displacement amount of the intensity pattern, and ii) to produce uncorrelated intensity patterns over at least one surface area A of the imaging sensor, for a plurality of respective incident monochrome beams of different wavelengths having a same wavefront shape.