Author Affiliations

Adam Vallés,^1,* Bereneice Sephton,² Isaac Nape,² Mitchell A. Cox,³ Fabian Steinlechner,⁴ Thomas Konrad,⁵ Juan P. Torres,¹ Filippus S. Roux,⁶ and Andrew Forbes²

¹ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona) 08860, Spain

²School of Physics, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa

³School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa

⁴Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, 07745 Jena, Germany

⁵School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa

⁶National Metrology Institute of South Africa, Meiring Naudé Road, Brummeria, Pretoria 0040, South Africa

^*Corresponding author: adam.valles@icfo.eu