Nicholas is a postdoctoral research fellow in Prof. Mark Brongersma’s group at the Geballe Laboratory for Advanced Materials (GLAM), Stanford University. His research is supported by a science fellowship from the German National Academy of Science - Leopoldina. His research interests include nanophotonics, optoelectronics, plasmonics, photonic integration, quantum photonics, nonlinear optics, photon-emitter interfaces, emission enhancement of quantum emitters, active metasurfaces, and phase change materials.

Nicholas is an experimental condensed matter physicist. After obtaining Master's degrees in Physics (RWTH Aachen) and Nanotechnology (Sorbonne), Nicholas began his Ph.D. at Imperial College London. During his Ph.D., he focused on light-matter interaction on the nanoscale, hot-carrier photodetection, and hybrid photonic-plasmonic waveguides. His supervisors were Prof. Stefan Maier and Prof. Rupert Oulton. He completed his Ph.D. in 2020, for which he was awarded the Imperial College Solid State Physics Thesis Prize 2020 for the best thesis. Shortly after, he joined a startup company in Switzerland working on the development of high-speed optical interconnects.

In 2021, he was awarded the competitive Science Fellowship from the German National Academy of Science - Leopoldina, which has been supporting his research at Stanford. At Stanford University, he works on active solid-state optical interfaces with two main research directions: i) quantum emitter control in integrated photonic networks and ii) reconfigurable beam steering in phase change material-based metasurfaces.

Honors & Awards

  • Leopoldina Postdoctoral Fellowship, German National Academy of Science (2021)
  • Imperial College Solid state thesis prize 2020, Imperial College London (2020)
  • Deutschlandstipendium - Scholarship awarded for outstanding achievements in physics, Education Fund of the Federal Ministry 2016 of Education and Research Germany (2016)
  • Listed on the Dean’s List- Ranked in the upper 5% of the class out of 300 students in Economics., RWTH Aachen (2015)
  • Deutschlandstipendium - Scholarship awarded for outstanding achievements in physics, Education Fund of the Federal Ministry of Education and Research Germany (2015)

Professional Education

  • Master of Science, Rheinisch-Westfalische Technische Hochschule (2017)
  • Master of Science, Rheinisch-Westfalische Technische Hochschule (2016)
  • Doctor of Philosophy, Imperial College of London (2020)
  • Bachelor of Science, Rheinisch-Westfalische Technische Hochschule (2023)
  • Master of Science, Sorbonne Universite (2015)
  • PhD, Imperial College London, Experimental Solid State Physics (2020)
  • MS, RWTH Aachen University, Physics (2016)

Stanford Advisors


  • Nicholas Guesken, Alberto Lauri, Yi li. "United States Patent US20220209038A1 Schottky-barrier type infrared photodetector", Jun 30, 2022
  • Nicholas Guesken, Florin Püntener, Wolfgang Heni. "United StatesLoss mitigation of plasmonic waveguides, application: PCT/EP2022/075251", Feb 1, 2022

Lab Affiliations

All Publications

  • Emission enhancement of erbium in a reverse nanofocusing waveguide. Nature communications Güsken, N. A., Fu, M., Zapf, M., Nielsen, M. P., Dichtl, P., Röder, R., Clark, A. S., Maier, S. A., Ronning, C., Oulton, R. F. 2023; 14 (1): 2719


    Since Purcell's seminal report 75 years ago, electromagnetic resonators have been used to control light-matter interactions to make brighter radiation sources and unleash unprecedented control over quantum states of light and matter. Indeed, optical resonators such as microcavities and plasmonic antennas offer excellent control but only over a limited spectral range. Strategies to mutually tune and match emission and resonator frequency are often required, which is intricate and precludes the possibility of enhancing multiple transitions simultaneously. In this letter, we report a strong radiative emission rate enhancement of Er3+-ions across the telecommunications C-band in a single plasmonic waveguide based on the Purcell effect. Our gap waveguide uses a reverse nanofocusing approach to efficiently enhance, extract and guide emission from the nanoscale to a photonic waveguide while keeping plasmonic losses at a minimum. Remarkably, the large and broadband Purcell enhancement allows us to resolve Stark-split electric dipole transitions, which are typically only observed under cryogenic conditions. Simultaneous radiative emission enhancement of multiple quantum states is of great interest for photonic quantum networks and on-chip data communications.

    View details for DOI 10.1038/s41467-023-38262-6

    View details for PubMedID 37169740

    View details for PubMedCentralID PMC10175264

  • Emission enhancement of erbium in a reverse nanofocusing waveguide Nature Communications Güsken, N. A., et al 2023; 14 (2719)
  • Near-unity Raman beta-factor of surface-enhanced Raman scattering in a waveguide. Nature nanotechnology Fu, M., Mota, M. P., Xiao, X., Jacassi, A., Gusken, N. A., Chen, Y., Xiao, H., Li, Y., Riaz, A., Maier, S. A., Oulton, R. F. 2022


    The Raman scattering of light by molecular vibrations is a powerful technique to fingerprint molecules through their internal bonds and symmetries. Since Raman scattering is weak1, methods to enhance, direct and harness it are highly desirable, and this has been achieved using optical cavities2, waveguides3-6 and surface-enhanced Raman scattering (SERS)7-9. Although SERS offers dramatic enhancements2,6,10,11 by localizing light within vanishingly small hot-spots in metallic nanostructures, these tiny interaction volumes are only sensitive to a few molecules, yielding weak signals12. Here we show that SERS from 4-aminothiophenol molecules bonded to a plasmonic gap waveguide is directed into a single mode with >99% efficiency. Although sacrificing a confinement dimension, we find a SERS enhancement of ~103 times across a broad spectral range enabled by the waveguide's larger sensing volume and non-resonant waveguide mode. Remarkably, this waveguide SERS is bright enough to image Raman transport across the waveguides, highlighting the role of nanofocusing13-15 and the Purcell effect16. By analogy to the beta-factor from laser physics10,17-20, the near-unity Raman beta-factor we observe exposes the SERS technique to alternative routes for controlling Raman scattering. The ability of waveguide SERS to direct Raman scattering is relevant to Raman sensors based on integrated photonics7-9 with applications in gas sensing and biosensing.

    View details for DOI 10.1038/s41565-022-01232-y

    View details for PubMedID 36302960