Holographic Wavefront Sensing Using Opaque Dot Lattice
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wavefront sensing methods are limited by complex setups and require bulky equipment, such as diffractive optical elements or lenslet arrays, which hinder compactness and simplicity.
Innovation Solution
A holographic wavefront sensing method using a transparent substrate with a lattice of opaque dots, where the interference pattern formed by diffracted and undiffracted light is detected by an image sensor, allowing for in-line hologram formation and digital reconstruction of the wavefront without the need for complex optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interferometry is used for wavefront sensing, then measurement precision is improved, but device complexity increases due to bulky setup requiring beam splitting and combining
Solution Approach 1:
The patent combines the reference beam and object beam paths into a single in-line configuration. The lattice structure serves both as a diffraction element and a reference, eliminating the need for separate beam splitting and combining optics. This merging of optical paths directly reduces device complexity while maintaining interferometric measurement precision.
Solution Approach 2:
The patent extracts the beam splitting and combining functions from the traditional interferometric setup by using the lattice structure itself to generate the reference diffraction orders. This removes bulky optical elements and simplifies the overall system architecture while preserving the interferometric measurement capability.
2Measurement precision
If diffractive optical element with Zernike mode holograms is used, then wavefront sensing capability is improved, but device complexity increases due to complex optical element design
Solution Approach 1:
The patent changes the parameters of the lattice structure (spacing, size, arrangement of dots) to encode different Zernike mode information. Instead of using complex pre-calculated holograms, the system uses adjustable lattice parameters to adapt to different wavefront aberration modes, simplifying the optical element while maintaining measurement precision.
Solution Approach 2:
The patent segments the wavefront measurement into discrete sampling points across the lattice structure. Each lattice point contributes to measuring specific aberration modes, allowing the complex wavefront to be broken down into manageable discrete measurements that are then reconstructed digitally.
3Productivity
If Shack-Hartmann sensor with lenslet array is used, then wavefront sampling capability is improved, but measurement precision is limited by lenslet array pitch
Solution Approach 1:
The patent creates a digital copy of the lattice structure through computational reconstruction algorithms. This digital replica allows for super-resolution processing and post-processing enhancement that overcomes the physical sampling limits of the lattice pitch, effectively decoupling measurement precision from the physical element size.
Solution Approach 2:
The patent transitions from direct spatial sampling in the optical domain to computational analysis in the digital domain. By moving the measurement analysis to another dimension (computational space), the system achieves higher effective resolution than the physical lattice pitch would normally permit.
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 a compact, simple setup for high-resolution wavefront sensing, capable of determining wavefront distortions and aberrations with reduced computational complexity, applicable to various light sources and wavelengths.
Implementation Method 1
an interference pattern formed by diffracted light, being scattered by the opaque dots, and undiffracted light of the light beam received by the image sensor
Implementation Method 2
an interference pattern formed by diffracted light, being scattered by the opaque dots, and undiffracted light of the light beam received by the image sensor
Data Source
Figure 1~2a
Figure 2b~2c
Figure 2d~2e
AI summary
A method of holographic wavefront sensing is disclosed. The method comprises: receiving (302) a light beam (202) on a transparent, flat substrate (102), provided with a lattice (104) of opaque dots (106); detecting (304) by an image sensor (108) an interference pattern (204) formed by diffracted light, being scattered by the opaque dots (106), and undiffracted light of the light beam (202); processing (306) the detected interference pattern (204) to digitally reconstruct a representation of a displaced lattice (206), which would form the interference pattern (204) on the image sensor (108) upon receiving the light with a known wavefront; and comparing (308) the representation of the displaced lattice (206) to a known representation of the lattice (104) to determine a representation of the wavefront form of the received light beam (202). An apparatus (100) and a system (400) for holographic wavefront sensing are also disclosed.