Coherent Diffractive Imaging Arbitrary Incidence Angle

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Solution Overview

Problem

Conventional coherent diffractive imaging (CDI) techniques are limited to normal incidence, restricting imaging geometry, resulting in low resolution and limited scattering availability for detection, especially in reflection modes, and require time-consuming remapping processes.

Innovation Solution

The development of methods and apparatus for CDI with arbitrary angle of incidence, utilizing short-wavelength UV sources and fast numerical processing for diffraction pattern remapping, enabling efficient imaging with high numerical aperture and multi-wavelength illumination, and employing off-axis focusing optics and high-order harmonic generation for improved resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional CDI techniques use normal incidence or near-normal incidence, then the imaging geometry is simple and easy to implement, but the resolution is limited and scattering availability is restricted

Engineering Contradiction:
ImproveresolutionVSAvoidimaging geometry complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment of the angle of incidence to optimize imaging quality. By varying the incidence angle during the imaging process, the system can adapt to different scattering conditions and improve resolution without being constrained to a fixed geometric configuration, thus resolving the contradiction between simplicity and performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of incidence angle from fixed (normal or near-normal) to variable (arbitrary angles including grazing angles). This parameter change enables access to additional scattering channels and improves resolution while maintaining computational efficiency through the developed remapping method, addressing both resolution improvement and geometric flexibility.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If reflection CDI uses grazing incidence, then scattering availability increases and resolution improves, but the remapping process becomes time-consuming

Engineering Contradiction:
ImproveresolutionVSAvoidremapping time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the computationally intensive triangulation-based remapping method with a faster interpolation-based approach. By substituting the mechanical/geometric triangulation process with a more efficient numerical interpolation method, the system achieves the same remapping function with significantly reduced computational time, resolving the contradiction between resolution improvement and processing speed.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an intermediate uniform frequency grid that copies the structure of the final desired grid, allowing direct mapping from the detector grid without complex triangulation. This intermediate representation enables efficient remapping by interpolating values onto the intermediate grid, which is then transformed to the final grid, significantly reducing computation time while maintaining accuracy.

Inventive Principle:
Principle #26Copying

3Measurement precision

If CDI is limited to near-zero degrees incidence, then the computational processing is simple, but the reflectivity of objects is low and scattering is limited

Engineering Contradiction:
Improvescattering signal strengthVSAvoidcomputational processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent dynamically adjusts the incidence angle to optimize scattering signal strength. By varying the angle from near-zero to arbitrary angles, the system can exploit higher reflectivity and scattering effects that occur at larger angles, improving signal strength while managing computational complexity through efficient remapping algorithms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary calculation of the remapping kernel and intermediate grid transformation matrices before the actual imaging process. By pre-computing these computational resources, the system reduces the computational burden during data acquisition and processing, enabling arbitrary angle imaging without excessive computational complexity.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If the numerical aperture is increased for high-resolution imaging, then the resolution improves, but the complexity of the imaging system increases

Engineering Contradiction:
ImproveresolutionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent develops a universal remapping method that works for arbitrary angles of incidence, making the imaging system adaptable to multiple configurations without requiring separate specialized processing pipelines. This multi-functional approach allows high-NA imaging at any angle while using the same computational framework, reducing overall system complexity despite the increased capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 high-resolution, wavelength-limited imaging at arbitrary angles of incidence, improving imaging geometry and computational efficiency, and allowing for dynamic and hyperspectral imaging with high numerical aperture, suitable for various CDI configurations.

Implementation Method 1

The present invention relates to microscopy and other forms of imaging using coherent light

Methodology Applied
Scientific EffectCoherent light: Coherent Light

Implementation Method 2

coherent diffractive imaging (GDI) with an arbitrary angle of incidence

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

focusing optic(s) to condense the light onto the sample

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 4

transmitted scattering field 12 is measured on detector 13

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP3186616B1Coherent diffractive imaging with arbitrary angle of incidence
Publication Date: 2019.12.18 THE REGENTS OF THE UNIVERSITY OF COLORADO
  • EP3186616B1 patent drawingFigure 1A~1C
  • EP3186616B1 patent drawingFigure 2A
  • EP3186616B1 patent drawingFigure 2B

AI summary

Apparatus and methods for coherent diffractive imaging with arbitrary angle (17) of illumination (20, 21) incidence utilize a method of fast remapping of a detected diffraction intensity pattern (212) from a detector pixel array (initial grid) (27) to a uniform spatial frequency grid (final grid) (202) chosen to allow for FFT on the remapped pattern. This is accomplished by remapping the initial grid to an intermediate grid chosen to result in a final grid that is linear in spatial frequency. The initial grid is remapped (generally by interpolation) to the intermediate grid that is calculated to correspond to the final grid. In general, the initial grid (x,y) is uniform in space, the intermediate grid (x, y) is non-uniform in spatial frequency, and the final grid (fx, fy) is uniform in spatial frequency.