Regensburg 2007 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 15: Poster Session
DS 15.23: Poster
Dienstag, 27. März 2007, 15:00–17:00, Poster B
Retardation correction for PEM based multi-channel reflectance difference spectroscopy — •Chunguang Hu1, 2, Lidong Sun1, Michael Hohage1, J. Flores-Camacho1, Peter Zeppenfeld1, and Xiaotang Hu2 — 1Institute of experimental physics, Johannes Kepler University Linz, Linz, Austria — 2Key lab of precision measurement technology and instrument, Tianjin University, Tianjin, China
Reflectance difference spectroscopy (RDS) is a highly surface sensitive optical probe, providing information on the surface structure, morphology, and electronic properties. To realize the fast spectroscopy measurement, several photoelastic modulator (PEM) based multi-channel RDS systems have been developed [1, 2]. A general problem that arises in this type of RDS setup is the wavelength dependence of the PEM. Different from the more conventional setup, for a multi-channel RDS, PEM voltage must be held fixed while all the channels are detected simultaneously. As a result, the retardation of PEM is unequal for different wavelengths and the optimized condition is only fulfilled for a single wavelength. Consequently, a retardation correction is necessary for other wavelengths. Here, we introduce two generalized methods for the retardation correction in which the wavelength dependence of birefringence coefficient has also been taken into consideration. The result is compared with that reported in [1, 2].
[1] C. Kaspari et al, Phys. Stat. Sol. (b) 242, 2561 (2005).
[2] P. Harrison et al, Meas. Sci. Technol. 12, 2185 (2001).