Abstract

Fabry-Perot etalons with birefringent substrates are studied for application to the measurement of the spectral profile of faint solar corona emission lines. The method uses polarization spectral chopping by means of a photoelastic modulator that allows alternate measurements of the radiation within the bandwidth corresponding to the coronal line and orthogonally polarized radiation in a similar adjacent bandwidth. These two bands are isolated from their associated channeled spectra by an interference filter. Electronic subtraction gives the coronal signal. The line profile is obtained by successive sampling through the line. Design parameters of the etalons such as the interorder spectral interval, the spectral interval between orthogonally polarized components, the bandwidth, transmittance, and the angular characteristics are investigated for optimum performance.

© 1987 Optical Society of America