Hinrichs, K.; Shaykhutdinov, T.; Rappich, J.; Kratz, C.; Furchner, A.: IR laser polarimetry: Breaking limits of FTIR polarimetry for thin film studies. In: Israel Gannot, Katy Roodenko [Ed.] : Optical Fibers and Sensors for Medical Diagnostics, Treatment and Environmental Applications XXI : Event SPIE BIOS, 6-12 March 2021, Online Only, California, United StatesBellingham: SPIE, 2021 (Proceedings of SPIE ; 11635). - ISBN 978-1-5106-4106-8, p. 116350U/1-6
10.1117/12.2580709
Abstract:
Advances in polarimetric techniques are of high interest in multiple scientific fields. Polarimetry characterizes optical and material properties such as anisotropy and structure, which relate to physical, chemical and functional properties of materials used in optoelectronic, polymer, plasmonic, bio-related and pharmaceutical applications. Laser-based infrared (IR) spectroscopic methods beyond classical Fourier-transform infrared (FTIR) spectroscopy enable previously impossible polarimetric investigations from macroscopic to nanoscopic length scales. This contribution focuses on new polarimetry techniques for detailed analyses of structural and material properties of thin films and surfaces. Specifically, we show applications of two laboratory-based instruments that employ tunable quantum cascade lasers (QCLs) from Daylight Solutions as brilliant light sources. Regarding far-field IR spectroscopic measurements, a novel laser ellipsometer (built in cooperation with Sentech Instruments) simultaneously measures spectral amplitude and phase information via single-shot detection of four different polarization states. The device reaches temporal resolutions in the μs to ms range at high spectral (< 0.5 cm−1 ) and lateral resolutions (≤ 125μm). At the nanoscale, photothermal atomic force microscopy (AFM)-IR (Anasys, Bruker), based on a QCL and a polarizing unit, enables polarimetry with lateral resolutions of a few 10 nm.