Data reduction for spatially resolved reflectance anisotropy spectrometer

• Published in: Review of scientific instruments 2023-10, Vol.94 (10)
• Main Authors: Rodríguez-Salas, L., Lastras-Martínez, A., Núñez-Olvera, O. F., Lastras-Montaño, M. A., Castro-García, R., Balderas-Navarro, R. E., Lastras-Martínez, L. F.
• Format: Article
• Language: English
• Subjects: Anisotropy; Data reduction; Incident light; Photomultiplier tubes; Reflectance; Scientific apparatus & instruments; Signal to noise ratio; Singular value decomposition; Spectrometers
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/5.0162116

We show that in spatially resolved reflectance anisotropy (RA) spectrometers, off-axis optical rays introduce a spurious signal component that cannot be addressed by optical alignment. Such a component is associated with the difference between the reflectivities s and p of the sample and depends, in a complex manner, on the incidence position of the incident light on the surface of the sample. We report a data-reduction procedure to easily identify and remove spurious RA signals associated with the off-axis optical rays, based on the singular value decomposition analysis of spatially resolved RA spectra. We validated this approach by developing a spatially resolved RA spectrometer based on an 8 × 8 multi-anode photomultiplier (PMT). The PMT allowed the use of phase-sensitive detection techniques to enhance the signal-to-noise ratio, which is essential for the evaluation of the proposed data reduction procedure.