Title
Vision-Based Alignment Control for Grating Tiling in Petawatt-Class Laser System
Abstract
Large-sized diffraction gratings are required for the compressor of chirped-pulse-amplification systems. However, producing single large grating is of great difficulty, which makes grating tiling an alterative solution. This paper presents a vision-based alignment control method for grating tiling in petawatt-class laser system. Tiling errors with six degrees of freedom are grouped into three ones, and a decoupled vision control method is proposed. The piston error is measured from the far-field focal-spot image. To determine the piston error, the energy ratio between the main and secondary spots in the image is computed, and then a mapping formulation is determined to compute the piston from the energy ratio. To guarantee precision and reliability, a closed-loop piston control system with clustering error filtering and output verification is designed. The angular error is composed of two parts, i.e., tip and tilt errors, which is measured from the near-field interference fringe image. To reduce the influence of airflow on the angular measurement, a novel image quality estimation method is designed using the average crest-to-trough difference. Then, Fourier fringe pattern analysis is applied to the left and right parts of the image to reconstruct the wavefront, based on which a closed-loop grating angular control system is designed. Finally, experiments are well conducted in a tritiled gratings to verify the performance and precision of the proposed grating tiling system.
Year
DOI
Venue
2014
10.1109/TIM.2013.2285792
IEEE T. Instrumentation and Measurement
Keywords
Field
DocType
decoupled vision control method,near-field interference fringe image,spatial filters,fourier transform optics,optical pulse compression,closed-loop piston control system,tilt error,piston error,far-field focal-spot image,energy ratio,diffraction gratings,image quality estimation method,light interference,tip error,angular measurement,vision-based alignment control,angular error,wavefront,grating tiling,fringe image,image reconstruction,fourier fringe pattern analysis,chirped-pulse-amplification system compressor,focal-spot image,output verification,mapping formulation,wavefront reconstruction,optical design techniques,visual control,petawatt-class laser system,clustering error filtering,wavefront.,closed loop systems,interference,large-sized diffraction gratings,closed-loop grating angular control system,measurement uncertainty,pistons,diffraction,control systems
Wavefront,Grating,Piston,Six degrees of freedom,Image quality,Optics,Filter (signal processing),Electronic engineering,Diffraction grating,Interference (wave propagation),Mathematics
Journal
Volume
Issue
ISSN
63
6
0018-9456
Citations 
PageRank 
References 
0
0.34
8
Authors
6
Name
Order
Citations
PageRank
Zaojun Fang198.76
Lan Xia200.34
Guodong Chen371.59
Yanlong Huang480.92
De Xu5332.72
Min Tan62342201.12