Resonant Plasmonic Metasurfaces for Quantum Photonics: From 2D Material-Based Photodetectors to Superconducting Single-Photon Detectors

Resonant plasmonic metasurfaces based on quasi-epitaxially grown transition metal nitrides offer a powerful platform to enhance light–matter interaction for quantum photonic applications. We demonstrate that integrating niobium nitride superconducting microwire single-photon detectors with gap plasmon resonators achieves a remarkable 233-fold enhancement in phonon–electron coupling and 98% detection efficiency under visible illumination. Concurrently, wafer-scale monolayer MoS₂ photodetectors combined with hafnium nitride plasmonic metasurfaces exhibit over 100 photocurrent enhancement, achieving record detectivity of 2.58×10¹² Jones and ultra-low dark current. The ceramic plasmonic structures create strong localized fields that amplify photogating effects. These results highlight how quasi-epitaxial transition metal nitrides, serving as superconducting materials and plasmonic resonators, can simultaneously boost the efficiency and sensitivity of ultrathin quantum photonic devices. Potential applications span quantum communication, advanced sensing, and optical computing.

Speaker Biography
Dr. Yu-Jung Lu is an Associate Research Fellow at the Research Center for Applied Sciences, Academia Sinica, and an Associate Professor in the Department of Physics at National Taiwan University. She earned her Ph.D. in Physics from National Tsing Hua University, Taiwan, in 2013 and later joined Caltech as a postdoctoral researcher from 2015 to 2017. Dr. Lu is a renowned materials physicist specializing in active plasmonics, nanophotonics, and metasurfaces. Her recent research has focused on developing novel ceramic plasmonic materials based on conductive transition metal nitrides (such as TiN, HfN, NbN, ZrN, and NbTiN). These materials offer high-temperature stability, tunable optical properties, and CMOS compatibility, making them promising alternatives to conventional noble metals. She has systematically explored their plasmonic behavior and engineered nanostructures to enhance light–matter interactions at the nanoscale, leading to significant advancements in energy conversion, sensing, and quantum photonic applications.
In particular, Dr. Lu is pioneering efforts to apply transition metal nitride-based plasmonics in superconducting single-photon detectors (SSPDs), aiming to improve their detection efficiency and spectral response. This line of research not only bridges the gap between nanophotonics and quantum technology but also opens new directions for next-generation optoelectronic devices. Her work has led to the discovery of several unique operating mechanisms using plasmonic nanostructures to manipulate the local electromagnetic field and boost nanoscale interactions. The relevant research is currently conducted in collaboration with TSMC. Dr. Lu is deeply committed to advancing the fields of nanophotonics, plasmonics, and metamaterials.
She has chaired, co-chaired, and served on committees for international symposiums such as GNP, MRS Fall, META, SPIE O+P, and CLEO Pacific Rim. In 2021, she was selected as one of the SPIE Women in Optics Planners and has delivered over 50 invited talks at international nanophotonics conferences. As a mentor, she has guided more than 65 graduate students, research assistants, and postdocs, cultivating the next generation of researchers. She currently serves as an Associate Editor for APL Quantum, Advanced Photonics, and the Journal of Lightwave Technology. Her contributions have earned her numerous honors, including the Career Development Award (2018), the Youth Optical Engineering Medal (2020), SPIE Senior Member (2023), MRS Early Career Distinguished Presenters (2024), Future Tech Award (2024), IEEE Senior Member (2025) and iSPN Young Researcher Award (2025). Her research is widely published in high-impact journals such as Nature Communications, Nano Letters, ACS Nano, ACS Photonics, Nature Nanotechnology, and Science.