A new method to detect molecular ions selectively in gas discharges by Fourier transform emission spectroscopy is proposed. This method is by dual-beam optical subtraction. The difference spectrum between blue and red Doppler-shifted components is obtained directly thus eliminating the large background that is due to neutral precursors.
© 1996 Optical Society of America
P. A. Martin and G. Guelachvili, "Selective detection of molecular ions in dc discharges by dual-beam Fourier transform spectroscopy," Appl. Opt. 35, 7066-7069 (1996)