SKM 2023 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 15: Optical Analysis of Thin Films II

DS 15.3: Vortrag

Donnerstag, 30. März 2023, 12:00–12:15, SCH A 316

Birefringence of orthorhombic DyScO3: Towards a terahertz quarter-wave plate — •Jingwen Li, Chia-Jung Yang, Jannis Lehmann, Nives Strkalj, Morgan Trassin, Manfred Fiebig, and Shovon Pal — D-MATL, ETH Zurich, Switzerland

The energy scale of THz light corresponds to plenty of the fundamental collective excitations in materials, such as phonons, magnons, and heavy fermions. This makes THz light an ideal tool to investigate the low-energy excitations and non-equilibrium processes in solid-state systems. With the growing interest in studying the aforementioned collective phenomena, manipulating the polarization of THz light becomes necessary. However, prevailing THz waveplates, such as quarter-wave plates (QWPs) for generating circularly polarized THz light, typically suffer from various problems, including bulky size, complex fabrication, or narrow working ranges. Here, we present a broadband THz QWP based on a 50-µm-thick (110)-cut orthorhombic DyScO₃ (DSO) crystal. We show a polarimetry measurement to verify the polarization of the output CP-THz light and prove that our DSO plate behaves like a QWP over a broad frequency range of 0.50-0.70 THz with a phase tolerance of ±3%. We believe that our results expand the choices of broadband THz QWPs, as well as the possibilities of simple and compact achromatic THz QWPs by combining DSO crystals. Most importantly, as a common substrate for growing various thin films, DSO shows its potential as a compact built-in broadband THz waveplate for thin film research with circularly polarized THz light. [1]

[1] Appl. Phys. Lett. 118, 223506 (2021).