Abstract

A novel method of determining both the Doppler and Stark shifts in a single measurement of spectral lines emitted by the arc-heated flow from a plasma jet has been successfully demonstrated. The method uses a spherical mirror arranged with its optical axis coincident with the optical axis of a Fabry-Perot interferometer and with its center of curvature at the center line of the flow. The common optical axis lies at an angle to the flow. With this system, both red- and blue-shifted line profiles are recorded in the same spectral scan. If conditions are such that the red- and blue-shifted profiles are not resolvable, the blue-shifted component is chopped so that the recorded signal consists of the envelopes of both the red-shifted profile and the superimposed red- and blue-shifted profiles. The wavelength difference between the blue- and red-shifted line profiles is exactly twice the Doppler shift integrated along a line of sight through the flow and is independent of a Stark shift. The Stark shift is given by the wavelength difference between the absolute line center and the midpoint of the red- and blue-shifted lines. Abel inversion of integrated line shift data has yielded radial velocity profiles to an accuracy of ±3% in a supersonic, arc-heated argon flow.

© 1972 Optical Society of America

Fabry-Perot Spectrometer Adjustment for the Compensation of Doppler Shift from Rapidly Rotating and Rapidly Flowing Sources

J. T. Trauger and F. L. Roesler
Appl. Opt. 11(9) 1964-1969 (1972)

Quantifying Doppler angle and mapping flow velocity by a combination of Doppler-shift and Doppler-bandwidth measurements in optical Doppler tomography

Daqing Piao and Quing Zhu
Appl. Opt. 42(25) 5158-5166 (2003)

Quantitative Schlieren Techniques Applied to High Current Arc Investigations

U. Kogelschatz and W. R. Schneider
Appl. Opt. 11(8) 1822-1832 (1972)

Doppler angle and flow velocity mapping by combined Doppler shift and Doppler bandwidth measurements in optical Dopplertomography

Daqing Piao, Linda L. Otis, and Quing Zhu
Opt. Lett. 28(13) 1120-1122 (2003)

Seven-Channel Fabry-Perot Spectrum Analyzer Used in Laser Scattering Measurements

P. K. John and R. Benesch
Appl. Opt. 11(1) 153-159 (1972)