Irregular Aperture Wavefront Sensing for High Dynamic Range
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Solution Overview
Problem
Existing wavefront sensors face limitations in measuring a large range of wavefront errors and tilts due to interference fringe density, focal spot displacement, and aperture constraints, leading to reduced measurement sensitivity and increased costs.
Innovation Solution
A wavefront sensor with an irregular aperture mask, diffuser, and camera system that separates incident light into discrete sub-regions, allowing for high dynamic range measurement by identifying sub-beam centroids and calculating wavefront errors based on their positions relative to reference positions and neighboring sub-beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interferometry is used to measure optical path difference with high accuracy, then measurement precision is improved, but measurement range is limited due to interference fringe density
Solution Approach 1:
The wavefront is divided into multiple sub-regions using an irregular aperture mask with multiple apertures. Each aperture creates a separate measurement zone, allowing the system to measure different portions of the wavefront independently. This segmentation enables the system to handle large wavefront errors by measuring sub-regions separately rather than requiring the entire wavefront to fit within a limited measurement range.
2Adaptability or versatility
If Shack-Hartmann sensors use larger lenslet diameter to increase measurement range, then measurement range is improved, but resolution is reduced due to fewer data points
Solution Approach 1:
The patent employs an irregular aperture mask where apertures are non-uniformly distributed across the mask surface rather than following a regular grid pattern. This asymmetric arrangement allows for optimized aperture placement that maximizes measurement range while maintaining sufficient data density for high resolution. The irregular spacing enables better utilization of the detector area and improves the system's ability to measure both small and large wavefront errors simultaneously.
3Adaptability or versatility
If autocollimator reduces focal length to increase field of view and measurement range, then measurement range is improved, but measurement sensitivity is reduced
Solution Approach 1:
The patent transitions from a single-point measurement approach to a multi-point simultaneous measurement approach by using multiple apertures across the mask. Instead of measuring one location at a time or requiring large focal lengths for wide field of view, the system captures wavefront information from multiple spatial locations simultaneously in a single measurement. This dimensional approach to measurement allows for both wide effective field of view and high sensitivity without the trade-off present in traditional autocollimator designs.
4Ease of manufacture
If wavefront sensor uses regular aperture mask with uniform spacing, then manufacturing is simplified, but ability to measure large wavefront errors is reduced
Solution Approach 1:
The patent employs an irregular aperture mask where apertures are non-uniformly distributed across the mask surface rather than following a regular grid pattern. This asymmetric arrangement allows for optimized aperture placement that maximizes measurement range while maintaining sufficient data density for high resolution. The irregular spacing enables better utilization of the detector area and improves the system's ability to measure both small and large wavefront errors simultaneously.
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 sensor achieves high dynamic range measurement of wavefront errors and tilts, overcoming limitations of traditional sensors by providing accurate measurements across a wide range with improved resolution and sensitivity, reducing the need for large detectors and expensive components.
Implementation Method 1
an aperture mask configured to receive incident light having a wavefront to be measured and including irregularly spaced apertures that respectively transmit sub-beams of the incident light
Implementation Method 2
a diffuser configured to receive the sub-beams transmitted by irregularly spaced apertures of the aperture mask
Data Source
AI summary
A wavefront sensor for measuring a wavefront that includes an aperture mask configured to receive incident light, the aperture mask comprising a plurality of apertures irregularly spaced and arranged in a plurality of sub-windows that respectively transmit sub-beams of the incident light. A diffuser can receive the sub-beams transmitted by the plurality of apertures. A controller of the sensor is configured to identify measured sub-beams by convolving the sub-beams imaged on the diffuser with a map of the plurality of apertures; and measure the wavefront of the incident light based on changes in position of the sub-beams in a digital image of the diffuser relative to both reference positions and neighboring sub-beams.