Mid- and far-infrared localized surface plasmon resonances in chalcogen-hyperdoped silicon.

Plasmonic sensing in the infrared region employs the direct interaction of the vibrational fingerprints of molecules with the plasmonic resonances, creating surface-enhanced sensing platforms that are superior to traditional spectroscopy. However, the standard noble metals used for plasmonic resonances suffer from high radiative losses as well as fabrication challenges, such as tuning the spectral resonance positions into mid- to far-infrared regions, and the compatibility issue with the existing complementary metal-oxide-semiconductor (CMOS) manufacturing platform. Here, we demonstrate the occurrence of mid-infrared localized surface plasmon resonances (LSPR) in thin Si films hyperdoped with the known deep-level impurity tellurium.

Applicability of the constitutive equations for the determination of the material properties of optically active materials.

For the description of the optical response of optically active media, different constitutive equations have been proposed and are still used in literature. Here, we demonstrate on potassium titanyl phosphate (KTiOPO) by means of ellipsometry that only the symmetric constitutive equation describes the observed spectra properly and allows the unique determination of the gyration tensor.