
Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Department Seminar
Host: Alexander Paarmann
Monday, June 16, 2025, 11:00 am
All are invited to meet around 10:40 am for a chat with coffee & cookies.
PC Seminar Room, G 2.06, Faradayweg 4
Michael T. Enders
ICFO – Institute of Photonic Sciences
α-MoO₃ for Phase Retardation and Chirality in the Mid-infrared Range
The blackbody spectrum at near-room temperature peaks in the mid-infrared (IR), making this range crucial for applications such as thermal energy harvesting, radiative cooling, spectroscopy, and mid-IR communications. However, there remains a lack of suitable optical components for manipulating IR light. We explore α-MoO₃, a low-dimensional material with strong, highly anisotropic optical phonons and hyperbolic dispersion in the mid-IR. While such properties have enabled exotic near-field effects, their observation typically requires complex instrumentation. In this talk, I will show that α-MoO₃ enables IR phase retardation and chiral light generation without nanofabrication. Using single flakes, we construct waveplate motifs that achieve polarization conversion in both transmission and reflection. By twisting flakes, we demonstrate near-unity circular birefringence - comparable to metasurfaces - and thermally driven chiral IR emission, all detectable via standard Fourier Transform Infrared Spectroscopy.