Invasive and Non-Invasive Observation of Occluded Fast Transient Events: Computational Tools

Photonics

Vijayakumar Anand¹  Soon Hock Ng¹  Tomas Katkus¹  Saulius Juodkazis¹ 

[1] Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia;

关键词: fast transient events;    high-speed imaging;    computational optics;    holography;    diffraction;    phase-retrieval algorithm;   

DOI  :  10.3390/photonics8070253

来源: DOAJ

【 摘 要 】

Industrial processes involving thermal plasma such as cutting, welding, laser machining with ultra-short laser pulses (nonequilibrium conditions), high temperature melting using electrical discharge or ion-beams, etc., generate non-repeatable fast transient events which can reveal valuable information about the processes. In such industrial environments containing high temperature and radiation, it is often difficult to install conventional lens-based imaging windows and components to observe such events. In this study, we compare imaging requirements and performances with invasive and non-invasive modes when a fast transient event is occluded by a metal window consisting of numerous holes punched through it. Simulation studies were carried out for metal windows with different types of patterns, reconstructed for both invasive and non-invasive modes and compared. Sparks were generated by rapid electrical discharge behind a metal window consisting of thousands of punched through-holes and the time sequence was recorded using a high-speed camera. The time sequence was reconstructed with and without the spatio-spectral point spread functions and compared. Commented MATLAB codes are provided for both invasive and non-invasive modes of reconstruction.

【 授权许可】

Unknown