High-speed high-resolution plasma spectroscopy using spatial-multiplex coherence imaging techniques

Abstract

We have recently obtained simultaneous two-dimensional (2D) plasmaDoppler spectroscopic images of plasma brightness, temperature, and flow fields. Using compact polarization optical methods, quadrature images of the optical coherence of an isolated spectral line are multiplexed to four quadrants of a fast charge-coupled device camera. The simultaneously captured, but distinct, images can be simply processed to unfold the plasma brightness, temperature, and flow fields. This static system, which is a spatial-multiplex variant of previously reported electro-optically modulated, temporal-multiplex coherence imaging systems, is based on a high-throughput imagingpolarizationinterferometer that employs crossed Wollaston prisms and appropriate image plane masks. Because the images are captured simultaneously, it is well suited to high-spectral-resolution, high-throughput 2D imaging of transient or rapidly changing spectroscopic scenes. To illustrate instrument performance we present recent results using a static 4-quadrant Dopplercoherence imaging on the H-1 heliac at the ANU.