Authors:	Wagner, Ford M Melnikas, Simas Cramer, Joel Damry, Djamshid A. Xia, Chelsea Q. Peng, Kun Jakob, Gerhard Kläui, Mathias Kičas, Simonas Johnston, Michael B.
Title:	Optimised spintronic emitters of terahertz radiation for time-domain spectroscopy
Online publication date:	19-Jun-2023
Year of first publication:	2023
Language:	english
Abstract:	Spintronic metal thin films excited by femtosecond laser pulses have recently emerged as excellent broadband sources of terahertz (THz) radiation. Unfortunately, these emitters transmit a significant proportion of the incident excitation laser, which causes two issues: first, the transmitted light can interfere with measurements and so must be attenuated; second, the transmitted light is effectively wasted as it does not drive further THz generation. Here, we address both issues with the inclusion of a high-reflectivity (HR) coating made from alternating layers of SiO2 and Ta2O5. Emitters with the HR coating transmit less than 0.1% of the incident excitation pulse. Additionally, we find that the HR coating increases the peak THz signal by roughly 35%, whereas alternative attenuating elements, such as cellulose nitrate films, reduce the THz signal. To further improve the emission, we study the inclusion of an anti-reflective coating to the HR-coated emitters and find the peak THz signal is enhanced by a further 4%.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-9194
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Journal of infrared, millimeter, and terahertz waves 44
Pages or article number:	52 65
Publisher:	Springer
Publisher place:	New York, NY
Issue date:	2023
ISSN:	1866-6892
Publisher DOI:	10.1007/s10762-022-00897-9
Appears in collections:	JGU-Publikationen