Characterization of background signals in wavelength-modulation spectrometry in terms of a Fourier based theoretical formalism

The detectability of wavelength-modulation (WM) diode-laser spectrometric t echniques is frequently limited by various background signals. A new theore tical formalism for WM spectrometry, based on Fourier analysis and therefor e capable of handling a variety of phenomena including the characterization and the analysis of analytical as well as background WM signals, was recen tly presented [Appl. Opt. 38, 5803 (1999)]. We report a detailed characteri zation of WM background signals from multiple reflections between pairs of surfaces in the optical system that act as etalons and from the associated intensity modulation in terms of this new formalism. The agreement between the background signals from a thin glass plate and those predicted by the f ormalism is good, which verifies the new Fourier analysis-based formalism. (C) 2001 Optical Society of America OCIS codes: 120.2230, 120.4820, 300.103 0, 300.6260, 300.6380.