Compressed Ultrafast Imaging VISAR for Shock Wave Diagnostics
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Solution Overview
Problem
Traditional imaging VISAR systems are limited to capturing only a single frame of two-dimensional images or multiple one-dimensional images, which restricts the ability to observe the dynamic process of shock waves in laser Inertial Confinement Fusion (ICF), leading to incomplete information and reduced targeting efficiency.
Innovation Solution
A compressed ultrafast imaging VISAR system is developed, incorporating a light source and target system, etalon interference system, compressed ultrafast imaging system, timing control system, and data processing system, which uses compressed ultrafast photography to reconstruct multi-frame three-dimensional images from two-dimensional space and one-dimensional time, enabling the restoration of complete dynamic processes of interference fringes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a traditional imaging device (area array CCD or streak camera) is used in imaging VISAR, then the device structure is simple and easy to operate, but only one frame of two-dimensional image or multi-frame one-dimensional images can be obtained during a single measurement, resulting in loss of information and inability to restore complete dynamic process
Solution Approach 1:
The patent transforms the measurement from traditional 2D spatial imaging to 3D spatiotemporal imaging by adding the time dimension. The compressed ultrafast imaging system captures the dynamic evolution process of shock wave velocity fields, converting single-frame 2D images into multi-frame 3D spatiotemporal data that preserves complete dynamic information.
Solution Approach 2:
The patent introduces a compressed sensing module as an intermediary between the light source and imaging device. This module encodes temporal information into spatial patterns, allowing a single measurement to capture multi-frame dynamic data. The compressed sensing algorithm then decodes this encoded information to reconstruct the complete dynamic process.
2Measurement precision
If a planar imaging VISAR is used to diagnose velocity field morphology, then the diagnostic ability for micro-disturbance is improved, but the ability to observe real-time dynamic process is lost due to single frame capture limitation
Solution Approach 1:
The patent performs preliminary encoding of temporal information into spatial patterns before the actual imaging measurement. The compressed sensing module pre-processes the dynamic information, embedding time evolution data into a single captured frame. This preliminary action allows subsequent decoding to reveal the complete dynamic process without requiring multiple sequential measurements.
Solution Approach 2:
The patent changes the measurement parameters from static single-frame capture to dynamic multi-frame reconstruction. By adjusting the compressed sensing encoding patterns and decoding algorithms, the system transforms a single spatial image into multiple temporal frames, effectively converting spatial measurement parameters into spatiotemporal measurement parameters.
3Loss of information
If multiple sequential measurements are performed to capture complete dynamic process, then information completeness is improved, but the measurement time increases and the transient process cannot be measured repeatedly
Solution Approach 1:
The patent merges multiple temporal measurements into a single spatial measurement. The compressed ultrafast imaging system combines the capture of multiple velocity field frames into one simultaneous measurement event. By encoding temporal sequences into spatial patterns, the system merges what would traditionally require multiple sequential measurements into a single captured frame.
Solution Approach 2:
The patent employs periodic encoding patterns in the compressed sensing module to capture temporal evolution. The encoding patterns are modulated at specific frequencies that correspond to the dynamic timescales of the shock wave, allowing periodic sampling of the dynamic process to be compressed into a single measurement that can be decoded into multiple frames.
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 significantly enhances imaging performance by achieving time resolution below 800 femtoseconds, imaging speed over 1.25×10^12 frames/second, and dynamic space resolution below 5 micrometers, thereby improving measurement precision and supporting precise diagnosis and pulse shaping in ICF processes.
Implementation Method 1
an etalon interference system (200), a compressed ultrafast imaging system (300)
Implementation Method 2
a velocity history of a surface to be detected is obtained based on beat frequency information carried by the probe light being reflected on the interface to be detected and a Doppler frequency shift principle
Data Source
AI summary
The present disclosure provides a compressed ultrafast imaging velocity interferometer system for any reflector, comprising a light source and target system, an etalon interference system, a compressed ultrafast imaging system, a timing control system and a data processing system. An imaging device in the traditional imaging velocity interferometer system for any reflector is replaced by a compressed ultrafast imaging system, a compressed ultrafast Photography (CUP) is introduced in an imaging process, multi-frame images, i.e. three-dimensional images for two-dimensional space and one-dimensional time, are reconstructed via a single measurement by a CUP-VISAR two-dimensional ultrafast dynamic image imaging, a complete dynamic process of a two-dimensional interference fringes image is restored, and spatiotemporal evolution information of a shock wave is effectively acquired, improving an imaging performance of the imaging velocity interferometer system for any reflector in dimension, and achieving a goal that could not be achieved before.