About

Simeon Bogdanov is an Assistant Professor of Electrical Engineering at the University of Illinois at Urbana-Champaign, a position he has held since January 2020. He completed his Ph.D. in Electrical Engineering at Northwestern University in 2014, after earning a Master’s degree in Microelectronics from the Royal Institute of Technology in Stockholm, Sweden, in 2008, and a Bachelor’s degree in Physics from Ecole Polytechnique in France in 2007. His research interests encompass applications of machine learning, integrated optoelectronics, and quantum photonics, with a focus on nano-photonics, quantum nanostructures for electronics and photonics, and advanced materials such as superconducting devices, plasmonics, and metamaterials. Bogdanov has contributed to the development of optical systems, quantum optics, cryptography, and information processing, and has authored numerous articles in leading scientific journals. He is a member of several professional societies, including the American Physical Society, SPIE, the Optical Society of America, and IEEE societies related to electron devices and photonics.

Research topics

• Quantum mechanics
• Physics
• Optoelectronics
• Optics
• Telecommunications
• Materials science
• Nanotechnology

Selected publications

• Novel nanodiamond color centers for quantum photonics and sensing

  2026-03-05

  article1st authorCorresponding
  PublisherDOI

• Fast quantum interferometry at the nanometer and attosecond scales with energy-entangled photons

  Science Advances · 2025-05-21 · 7 citations

  articleOpen access

  In classical optical interferometry, loss and background complicate achieving fast nanometer-resolution measurements with illumination at low light levels. Conversely, quantum two-photon interference is unaffected by loss and background, but nanometer-scale resolution is physically difficult to realize. As a solution, we enhance two-photon interference with highly nondegenerate energy entanglement featuring photon frequencies separated by 177 THz. We observe measurement resolution at the nanometer (attosecond) scale with only O (10 4 ) photon pairs, despite the presence of background and loss. Our nondestructive thickness measurement of a metallic thin film agrees with atomic force microscopy, which often achieves better resolution via destructive means. With contactless, nondestructive measurements in seconds or faster, our instrument enables metrological studies in optically challenging contexts where background, loss, or photosensitivity are factors.

  PublisherDOI

• Ultranarrow Bright Single-Photon Emitters in Diamond with Strong Broadband Phonon Decoupling

  ArXiv.org · 2025-11-09

  preprintOpen accessSenior author

  Single-photon emitters are fundamental building blocks for quantum information processing, communication and sensing. However, unwanted interactions with bulk phonons in their host environment strongly limit their coherence and controllability. We report single color centers in nanodiamonds that are strongly and comprehensively decoupled from the bulk phononic environment. The color centers feature record-narrow linewidths down to 0.3 nm at room temperature and stable, bright emission, exceeding 10 Mcps in saturation. Notably, the bulk phonon sideband is almost entirely suppressed, revealing the presence of a single localized vibrational mode outside the diamond phonon band. Our observations and simulations point towards a unique mechanism for phonon decoupling in common wide-gap materials, based on a strongly radiative orbital transition coupled to a localized vibrational mode. The new color center enables qualitatively higher performance for applications in quantum networks and nanoscale sensing, and the exploration of new physical resources associated with vibrational states.

  PublisherOA PDFDOI

• ANALYSIS OF THE PROPERTIES OF GREY FOREST SOILS IN RELATION TO FOREST TYPES IN NORTHEASTERN BULGARIA

  Ecological Engineering and Environment Protection · 2025-06-15

  articleOpen access1st authorCorresponding

  Modern forestry and forest soil science recognize soil as a key ecological factor for forest existence. Conversely, forest vegetation exerts a significant influence on soil profile development, weathering processes, and the transformation of organic matter within the soil. This interaction determines the specific morphology, composition, and properties of forest soils, justifying their formation as a result of forest soil-forming processes. This study presents results from an investigation of Gray Forest Soils (Gray Luvisols) under different forest types and in a non-forested area. The observed differences in soil morphological structure between forested and non-forested sites highlight the critical role of forest vegetation in shaping soil composition and properties. The study establishes that tree species characteristics influence variations in soil nitrogen content, pH, and the C/N ratio.

  PublisherDOI

• Feasibility of microwave-to-optical transduction via sub-terahertz states for sensing and quantum photonics

  2025-03-19

  article1st authorCorresponding
  PublisherDOI

• Low-temperature electron dephasing rates indicate magnetic disorder in superconducting TiN films

  ArXiv.org · 2025-10-23

  preprintOpen access

  We investigate electron transport and phase-breaking processes in thin titanium nitride (TiN) films of epitaxial quality. Previous studies show that a minute surface magnetic disorder significantly reduces the critical temperature ($T_\mathrm{c}$) and broadens the superconducting transition as the film thickness and device size decrease. We measure electron dephasing rates via magnetoresistance from $T_\mathrm{c}$ to $\sim 4T_\mathrm{c}$ in various-thickness TiN films. Electron dephasing occurs on the picosecond timescale and is nearly independent of temperature, differing from the expected inelastic scattering due to the electron-phonon and electron-electron interactions near $T_\mathrm{c}$, which occur over a nanosecond timescale. We propose spin-flip scattering as a possible additional phase-breaking mechanism. The significant increase in the dephasing rate for the thinnest film indicates that magnetic disorder resides near the surface of naturally oxidized films. Our research suggests that magnetic disorder may be a significant contributor to RF dissipation in superconducting devices based on TiN.

  PublisherOA PDFDOI

• Ultrafast plasmon-enhanced deterministically assembled single-photon sources based on nanodiamond color centers

  2025-03-21

  article1st authorCorresponding

  Color centers in nanodiamonds offer light-matter coupling rates in the near-THz range, and can be integrated with any photonic platform. They constitute promising building blocks for high-bandwidth quantum photonics, potentially at non-cryogenic temperatures. However, the properties of the color centers are heterogenous. To interface these emitters with the on-chip photonic circuitry one must pre-select and deterministically manipulate them with nanoscale precision. We will present a study of fundamental plasmon-enhanced emission rate limits in quantum emitters and a suite of recently developed techniques for realizing deterministically assembled plasmon-enhanced single-photon sources. These techniques include rapid automatic focusing, optical nanoparticle sizing, neural network-driven quantum optical measurements, probe-assisted nanoantenna assembly and the optical control of plasmonic cavity mode volume.

  PublisherDOI

• DYNAMICS OF CHANGES IN PROPERTIES OF CINNAMONIC FOREST SOILS INFLUENCED BY FOREST FIRES IN SOUTHWESTERN BULGARIA

  Ecological Engineering and Environment Protection · 2025-12-15

  articleOpen access1st authorCorresponding

  The forest fires are very common in the territory of Bulgaria, especially in cases of long summer droughts. They represent one of the most significant challenges in forest management, both from an economic and silvicultural perspective. The implementation of reforestation measures aimed at restoring destroyed forest ecosystems necessitates comprehensive studies on the changes in soil composition and properties. This paper presents results from a study on the dynamics of changes in the composition and properties of Cinnamonic Forest soils (Chromic Luvisols) affected by wildfires in Southwestern Bulgaria. The research examines changes in total carbon content, total nitrogen, pH levels, and the C/N ratio. The diverse nature of the factors influencing the dynamics of soil property alterations following wildfires underscores the need to investigate the consequences in each specific case of forest fire.

  PublisherDOI

• Low-temperature electron dephasing rates indicate magnetic disorder in superconducting TiN films

  Applied Physics Letters · 2025-10-23

  article

  We investigate electron transport and phase-breaking processes in thin titanium nitride (TiN) films of epitaxial quality. Previous studies show that a minute surface magnetic disorder significantly reduces the critical temperature (Tc) and broadens the superconducting transition as the film thickness and device size decrease. We measure electron dephasing rates via magnetoresistance from Tc to ∼4Tc in various-thickness TiN films. Electron dephasing occurs on the picosecond timescale and is nearly independent of temperature, differing from the expected inelastic scattering due to the electron–phonon and electron–electron interactions near Tc, which occur over a nanosecond timescale. We propose spin-flip scattering as a possible additional phase-breaking mechanism. The significant increase in the dephasing rate for the thinnest film indicates that magnetic disorder resides near the surface of naturally oxidized films. Our research suggests that magnetic disorder may be a significant contributor to RF dissipation in superconducting devices based on TiN.

  PublisherDOI

• Slow electron-phonon relaxation controls the dynamics of the superconducting resistive transition

  Physical review. B./Physical review. B · 2024-09-27 · 3 citations

  articleOpen access

  We investigate the temporal and spatial scales of resistance fluctuations ($R$ fluctuations) at the superconducting resistive transition accessed through voltage fluctuation measurements in thin epitaxial TiN films. This material is characterized by slow electron-phonon relaxation, which puts it far beyond the applicability range of the textbook scenario of superconducting fluctuations. The measured Lorentzian spectrum of the $R$ fluctuations identifies their correlation time, which is nearly constant across the transition region and has no relation to the conventional Ginzburg-Landau timescale. Instead, the correlation time coincides with the energy relaxation time determined by a combination of the electron-phonon relaxation and the relaxation via diffusion into reservoirs. Our data are quantitatively consistent with the model of spontaneous temperature fluctuations and highlight the lack of understanding of the resistive transition in materials with slow electron-phonon relaxation.

  PublisherOA PDFDOI

Frequent coauthors

• Vladimir M. Shalaev

  92 shared

• Alexandra Boltasseva

  Purdue University West Lafayette

  73 shared

• Alexander V. Kildishev

  43 shared

• Alexei Lagutchev

  38 shared

• Oksana Makarova

  Harvard University

  34 shared

• Mikhail Y. Shalaginov

  Massachusetts Institute of Technology

  33 shared

• Manijeh Razeghi

  28 shared

• Ilya A. Rodionov

  26 shared

Education

• PhD, Electrical Engineering and Computer Science

  Northwestern University

  2014

• MSc, Microelectronics

  Kungliga Tekniska Högskolan

  2008

• BSc, MSc

  Ecole Polytechnique

  2008

Awards & honors

• Alumni Award for Distinguished Service