Soft Glass Materials

Soft-glasses are a range of materials that has the potential to be transparent in the THz spectrum. These materials include glasses such as fluoride glasses (e.g. ZBLAN), chalcogenide (e.g. As₂S₃, As₂Se₃) and tellurite compounds. These materials have so far primarily been explored and used in the near- and mid-infrared spectrum, with only little work done in the THz spectrum.

With our ultrabroadband THz time domain spectrometer (TDS) we have the unique ability to measure the index and absorption for these materials at frequencies up towards 20 THz. We have recently investigated As₂S₃ and found two transparency windows, one at 7-8 THz and the other at 12.2 THz. These two transparancy windows are interesting for future nonlinear applications of chalcogenide in the THz range.

Chalcogenides are especially interesting to us, as it has a high nonlinearity as well as being an amorphous semiconductor. We are thus also working on measuring the Kerr nonlinearity and the photoconductive effect of various chalcogenide compounds. We have collaborations with other research groups, such as National Institute of R&D for Optoelectronics in Bucharest and Australian National University in Canberra, to provide us with chalcogenide samples to investigate.