CMQED group

Anne Le Floc'h

2026-10-15T08:02:23Z

Anne Le Floc'h is a PhD student focusing on memory effects induced by vortex dynamics in ultra-thin disordered Nb and NbN films for possible applications in superconducting electronics as memristor or self-learning artificial synapse for neuromorphic computations.

Lunding Guo

2026-10-14T15:37:56Z

Lunding is currently pursuing her PhD at ESPCI Paris, focusing on the design, fabrication, and characterization of superconducting nanowire single-photon detectors (SNSPDs) and their integration with hexagonal boron nitride (hBN). Her research aims to develop an integrated quantum photonic platform combining single-photon emission and detection on a chip.

Lunding received her Bachelor's degree in China and subsequently obtained her Master's degree in Quantum Engineering from École Normale Supérieure (ENS), Paris. Her previous research experience includes working on photodetectors based on two-dimensional transition metal dichalcogenides (TMDs) and quantum-dot-based whispering-gallery-mode microlasers.

She is currently pursuing her PhD at ESPCI Paris, focusing on the design, fabrication, and characterization of superconducting nanowire single-photon detectors (SNSPDs) and their integration with hexagonal boron nitride (hBN). Her research aims to develop an integrated quantum photonic platform combining single-photon emission and detection on a chip.

Ninghshun Chen

Alexis — 2026-10-02T13:22:47Z

Ning obtained his bachelor's degrees at the University of Virginia and worked as a software developer in the private industry. He then pursued a master's degree at the École Normale Supérieure in Paris. His internship work on the theory and simulation of Markovianity in light-matter excitation laid the foundation for his current research.This includes uncovering the impacts of static Coulomb interactions on nonlinear effects in highly-doped cavity-coupled asymmetric quantum well heterostructures.The results of these studies supplement his search for a full description of the ultrastrong light-matter coupled system's quantum properties. This requires going beyond the semiclassical factorization scheme by taking into consideration the microscopic quantum fluctuations in the optoelectronic devices.

Redza Zainudin

Alexis — 2026-04-30T09:04:18Z

Building a 100GHz qubit for quantum sensing applications

Redza studied at National University of Malaysia and did his master at the university of Tokyo. He discovered superconducting circuits during his internship in the Nakamura Group where he worked on the photon generation and absorption using a Fluxonium qubit. His PhD is part of the ANR project HyQD100. The goal is to develop a tunable mm-wave qubit which will be integrated with semi-conducting structures in order to detect and control condensed matter excitations.

Matéo Vernet

2025-10-20T07:28:49Z

Granular superconductors like Nb and NbN and how they can be used to create tunable quantum circuits.

Matéo Vernet has an engineering degree from ESPCI Paris and a master's degree in Physics of Complex Systems from Université Paris Cité. His research focuses on granular superconductors, such as niobium (Nb) and niobium nitride (NbN) thin films. Combining ion irradiation and electrostatic gating, he studies how geometrical disorder, magnetic impurities, and electrostatic fields change the micro- and macroscopic quantum behavior. In addition, his research encompasses a theoretical approach based on the localization landscape, which will offer novel insights into the spatial inhomogeneity and emergence of superconductivity in disordered and structured systems.

Qian Li

2025-10-20T07:28:33Z

QianLI has a background in material science, after getting her bachelor and master degrees in China, now she is a PhD student in ESPCI. Qian's research focuses on the development of high-temperature, ultra-fast Superconducting Nanowire Single Photon Detectors (SNSPDs) based on BSCCO (Bi2Sr2CaCu2O8+x), a van der Waals type-II high-temperature superconductor. Her work aims to fabricate large-area BSCCO flakes on borosilicate glass using anodic bonding technic and to integrate them with silver optical waveguides, finally develops an SNSPD that operates above 30K.

Dmitry Yakovlev

2025-10-20T07:28:25Z

Dr. Dmitry Yakovlev, currently a Postdoctoral Researcher at École supérieure de physique et de chimie industrielles de la Ville de Paris (ESPCI), specializes in condensed matter physics, focusing on superconducting quantum phenomena. With a PhD. from Higher school of Economics (HSE), his expertise spans nanofabrication, quantum computing, and Josephson junctions. Dmitry has contributed to advancements in superconducting single photon detectors and hybrid superconducting systems, and enjoys football, skiing, and diving.

Sergei Kozlov

2024-11-05T09:03:14Z

Educated at the Moscow State University at the faculty of Physical and Chemical Engineering. He started his first research steps in the Institute of Solid State Physics in Chernogolovka in the field of bose-condensation of interwell excitons but continued in the laboratory of superconductivity where he studied transport phenomena in nanowires. Then he did his PhD at ESPCI where he studied the critical behaviour of superconducting nanowires under the supervision of Dimitri Roditchev & Chéryl Feuillet-Palma. Now he is postdoc in the group CoQED studying the dynamics of Abrikosov vortices.

Alexis Jouan

Alexis — 2024-11-03T11:20:00Z

Alexis Jouan is an expert in superconductivity in mesoscopic systems. He performs high frequency measurements up to 100GHz to study the properties of electronic systems at cryogenic temperatures. He did a postdoc at the University of Sydney where he worked on the fabrication of topological Josephson junction in InAs quantum wells and performed new readout methods for spin qubits in Silicon. He also worked on the Fluxonium, a superconducting qubit during his postdoc in the quantum circuit group at ENS Lyon.

His research is focused on the study of quantum coherences in condensed matter physics. He designs, manipulate and measure electronic systems at very low temperature. Currently, he's working on new THz spectroscopy techniques based on superconducting circuits for the study of fundamental excitations in ferromagnetic materials or superconducting materials.

Yanko Todorov

Alexis — 2024-08-29T21:45:00Z

My research focuses on extreme electromagnetic regimes in optoelectronic devices operating in the mid- and far-infrared spectral domain (wavelength = 5 μm-300 μm, "TeraHertz"). In these structures a multitude of electrons trapped in artificial quantum potentials are ultra-strongly coupled with photons confined in microcavities or electromagnetic metamaterials. These structures allowed me to demonstrate and study the ultra-strong light-matter coupling regime in the THz domain for the first time. These studies led to new superradiant infrared emitters with high radiative performance and fast modulation speeds. They also provided new ultra-low noise infrared quantum detectors operating at high temperature with performance beyond the state of the art.
Today, I am particularly interested in the new quantum correlations that appear in this regime. I wonder about the possibilities of designing new experiments and optoelectronic devices where these quantum effects can be observed. In the long term, this activity should bring new insights into the field of quantum mechanics and enrich quantum technologies with new concepts.

After completing his secondary education in Bulgaria, Yanko Todorov arrived in France in 1997 to pursue his higher education in preparatory class at the Lycée Louis Le Grand. He studied in Ecole Normale Supérieure (Paris) in 1999-2001, and completed his doctoral thesis in 2006 at the Laboratory of Photonics and Nanostructure in Marcoussis (now C2N Laboratory). He then joined the QUAD team at the Laboratory of Materials and Quantum Phenomena (Université Paris Diderot) as a post-doc (2007-2009), and then CNRS researcher (2009-2019). After returning at ENS as a CNRS researcher (2019-2024), Yanko Todorov integrated Physics and Materials Laboratory (LPEM) at École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, ESPCI. There, Yanko Todorov co-founded the research group Condensed Matter Electrodynamics together with Alexis Jouan and Cheryl Feuillet-Palma.
Yanko Todorov's research focuses on the exploration of light-matter interaction in quantum devices operating in the mid- and far-infrared range. Among his notable achievements are : the study of the Purcell effect with quantum cascade emitters [1], the first experimental demonstration of the ultra-strong light-matter coupling regime in the TeraHertz domain [2], a new quantum description of collective phenomena related to ultra-strong coupling [3,4,5], as well as the demonstration of microcavity enhanced quantum detectors [6]. His worm also covers metamaterial architectures [7], both for unipolar devices [8] and optomechanical applications [9, 10].

Milestones :
2024 -present : CNRS Director of Research (DR-CNRS)
June 2020 : Defence of Habilitation à Diriger les Recherche (HDR) : “Exploring light-matter interaction at the nanoscale with infrared photons”
September 2019 : ERC Consolidator Grant “UNIQUE” (2020 – 2026)
2009 - 2024 : CNRS Researcher (CR-CNRS)
2007 – 2009 : Post-doctoral Research Associate/ Laboratoire de Matériaux et Phénomènes Quantiques, University Paris -Diderot, Paris, France
2006 – 2007 : Temporary Lecturer and Research Assistant/ Laboratoire de Matériaux et Phénomènes Quantiques, University Paris -Diderot / Paris/France
2002 - 2006 : PhD : Laboratory of Photonics and Nanostructures/University Paris VI/ France
2002 : Master (Quantum Physics), Ecole Doctorale 107, Ecole Normale Supérieur (Ulm)/Paris / France
1999-2002 : Bachelor's Degree at Ecole Normale Supérieure (Paris)
1997-1999 : Lycée Louis le Grand (Paris)

Selected Publications :
[1] “Purcell Enhancement of Spontaneous Emission from Quantum Cascades Inside Mirror-Grating Metal Cavities at THz Frequencies”, Y. Todorov, I. Sagnes, I. Abram and C. Minot, Phys. Rev. Lett. 99, 22 3603 (2007).
[2] “Ultrastrong Light-Matter Coupling Regime with Polariton Dots” , Y. Todorov, A. M. Andrews, R. Colombelli, S. De Liberato, C. Ciuti, P. Klang, G. Strasser, and C. Sirtori, Phys. Rev. Lett. 105, 196402 (2010).
[3] “Dipolar quantum electrodynamics theory of the three-dimensional electron gas”, Yanko Todorov, Phys. Rev. B 89, 075115 (2014).
[4] “Dipolar quantum electrodynamics of the two-dimensional electron gas”, Yanko Todorov, Phys. Rev. B 91, 125409 (2015).
[5] “Electronic transport driven by collective light-matter coupled states in a quantum device”
Francesco Pisani, Djamal Gacemi, Angela Vasanelli, Lianhe Li, Alexander Giles Davies, Edmund Linfield, Carlo Sirtori, and Yanko Todorov, Nature Communications 14, 3914 (2023).
[6] “Room temperature 9µm photodetectors and GHz heterodyne receivers”, D. Palaferri, Y. Todorov, A. Bigioli, A. Mottaghizadeh, D. Gacemi, A. Calabrese, A. Vasanelli, L. Li, A. G. Davies, E. H. Linfield, F. Kapsalidis, M. Beck, J. Faist, C. Sirtori, Nature 556 (7699), 85 (2018)
[7] “Absorption engineering in an ultra-subwavelength quantum system”, M. Jeannin, T. Bonazzi, D. Gacemi, A. Vasanelli, L. H Li, A. G. Davies, E. Linfield, C. Sirtori, and Y. Todorov, Nano Letters 20 (6) 4430–4436 (2020).
[8] “High temperature metamaterial TeraHertz quantum detector”, M. Jeannin, T. Bonazzi, D. Gacemi, A. Vasanelli, S. Suffit, L. Li, A. G. Davies, E. Linfield, C. Sirtori and Y. Todorov, Appl. Phys. Lett. 117, 251102 (2020).
[9] “Actively tunable laser action in GeSn nanomechanical oscillators”, Hyo-Jun Joo, Jiawen Liu, Melvina Chen, Daniel Burt, Baptiste Chomet, Youngmin Kim, Xuncheng Shi, Kunze Lu, Lin Zhang, Zoran Ikonic, Young-Ik Sohn, Chuan Seng Tan, Djamal Gacemi, Angela Vasanelli, Carlo Sirtori, Yanko Todorov, Donguk Nam, Nature Nanotechnology, 19, pages1116–1121 (2024).
[10] “Optomechanical terahertz detection with single meta-atom resonator”, C. Belacel, Y. Todorov, S. Barbieri, D. Gacemi, I. Favero, C. Sirtori, Nature Communications 8 (1), 1578 (2017).