Wavefront Encoding via Phase Grating for Single-Shot Laser Pulse Measurement
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Solution Overview
Problem
Current techniques for characterizing ultrashort laser pulses are limited by their need for time-consuming scanning methods, which are unsuitable for single-shot measurements and lack sufficient spatial and spectral resolution, making them impractical for high-intensity laser facilities and dynamic events.
Innovation Solution
A wavefront measuring apparatus and method using hyperspectral compressive wavefront sensing, which encodes phase information into a hypercube of light patterns and employs single-shot compressive imaging with a 2D sensor, combined with deep learning neural networks for real-time reconstruction, enabling improved spatial and spectral resolution without complex experimental setups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning methods are used to characterize ultrashort laser pulses, then measurement precision can be improved, but measurement time increases significantly and single-shot capability is lost
Solution Approach 1:
The patent encodes wavefront phase information into the spectral dimension by creating wavelength-dependent lateral shifts of light patterns. This allows the wavefront information to be captured simultaneously across all spatial and spectral dimensions in a single shot, eliminating the need for time-consuming scanning while maintaining high measurement precision through the added spectral encoding dimension
Solution Approach 2:
The patent applies a phase grating to pre-encode the wavefront phase information into lateral position shifts before detection. This preliminary encoding action transforms the invisible phase information into measurable spatial-spectral patterns that can be captured in a single shot, eliminating the need for subsequent scanning to extract wavefront information
2Measurement precision
If scanning methods are used, then spatial and spectral resolution can be improved, but the method becomes unsuitable for single-shot measurements and dynamic events
Solution Approach 1:
The patent utilizes the spectral dimension as an additional encoding channel, where different wavelengths experience different lateral shifts based on the wavefront phase. This spectral-spatial encoding allows simultaneous capture of high-resolution wavefront information across all wavelengths in a single shot, achieving both high resolution and single-shot capability
Solution Approach 2:
The phase grating performs preliminary encoding of wavefront information into spectral-spatial patterns before detection. This pre-encoding distributes wavefront information across multiple wavelengths and positions simultaneously, enabling high-resolution reconstruction from a single-shot measurement without requiring sequential scanning
3Measurement precision
If conventional wavefront sensing is used, then measurement accuracy can be maintained, but experimental setup complexity increases
Solution Approach 1:
The patent merges wavefront sensing with spectral analysis by using a single phase grating to simultaneously encode both wavefront phase information and spectral information into lateral position shifts. This unified approach eliminates the need for separate wavefront sensors and spectrometers, reducing experimental complexity while maintaining measurement accuracy
Solution Approach 2:
The patent employs a self-referenced measurement approach where the phase grating creates interference patterns that inherently contain both reference and test beam information. This self-service mechanism eliminates the need for external reference beams or complex calibration procedures, simplifying the experimental setup while preserving measurement accuracy
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 allows for rapid, high-resolution wavefront measurement of ultrashort laser pulses in a single shot, reducing measurement time and experimental complexity, facilitating real-time feedback control and expanded practical applications.
Implementation Method 1
a phase grating arranged for receiving the light field to be measured and creating ahypercube of light patterns by diffracting the light field
Implementation Method 2
a dispersive medium arranged for spectrally dispersing thehypercube of light patterns created by the phase grating onto the light sensor
Data Source
Figure 1~3
Figure 4A~4C
Figure 4D~5B
AI summary
A wavefront measuring apparatus 100 for sensing a light field 1, in particular of laser pulses, travelling along an optical axis (z) and having a lateral extension parallel to an optical plane (x-y) perpendicular to the optical axis, and for reconstructing a wavefront of the light field 1 with spatial and spectral resolution in the optical plane, comprises a wavefront encoding device 10 for receiving the light field 1 to be measured and for creating a hypercube 2 of light patterns encoding a phase of the wavefront by an intensity modulation in the optical plane and having spectral resolution within said optical plane, a wavefront sensing device 20 for capturing three dimensional wavefront data by single shot compressive imaging of the hypercube 2 of light patterns with a two dimensional light sensor 23, and a wavefront reconstructing device 30 for a neural network, in particular deep unrolling, based reconstruction of the wavefront of the light field 1 from the wavefront data. Furthermore, a wavefront measuring method and applications of measuring the wavefront are disclosed.