From Event: SPIE OPTO, 2018
We present the design of a novel scatterometer for precise measurement of the angular Mueller matrix profile of a mm- to µm-sized sample held in place by sound. The scatterometer comprises a tunable multimode Argon-krypton laser (with possibility to set 1 of the 12 wavelengths in visible range), linear polarizers, a reference photomultiplier tube (PMT) for monitoring the beam intensity, and a micro-PMT module mounted radially towards the sample at an adjustable radius. The measurement angle is controlled by a motor-driven rotation stage with an accuracy of 15’. The system is fully automated using LabVIEW, including the FPGA-based data acquisition and the instrument’s user interface. The calibration protocol ensures accurate measurements by using a control sphere sample (diameter 3 mm, refractive index of 1.5) fixed first on a static holder followed by accurate multi-wavelength measurements of the same sample levitated ultrasonically.
To demonstrate performance of the scatterometer, we conducted detailed measurements of light scattered by a particle derived from the Chelyabinsk meteorite, as well as planetary analogue materials. The measurements are the first of this kind, since they are obtained using controlled spectral angular scattering including linear polarization effects, for arbitrary shaped objects. Thus, our novel approach permits a non-destructive, disturbance-free measurement with control of the orientation and location of the scattering object.
© 2018 COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ivan Kassamakov, Göran Maconi, Antti Penttilä, Petteri Helander, Maria Gritsevich, Tuomas Puranen, Ari Salmi, Edward Hæggström, and Karri Muinonen, "Light scattering by ultrasonically-controlled small particles: system design, calibration, and measurement results," Proc. SPIE 10539, Photonic Instrumentation Engineering V, 105390R (Presented at SPIE OPTO: February 01, 2018; Published: 22 February 2018); https://doi.org/10.1117/12.2289079.
