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This internship/PhD thesis aims to explore these questions at the level of a single live cell, using the tools of quantum optomechanics, which enable unprecedented sensitivity and time-resolution [1]. In the last years, our team carried the first optomechanical experiments on biological objects, albeit in a dry environment where the biological functions were turned off [2,3]. More recently, we immersed optomechanical experiments in a physiological liquid medium in order to measure a living object in action, when biological mechanisms are this time turned on. The image shows an individual live cell deposited on the surface of an optomechanical disk (radius 11 μm) fabricated in our clean-room. The disk is evanescently coupled to a nanophotonic waveguide hold by two hexagonal pads, enabling real-time time optomechanical measurement of the cell. Building on this approach, the project will investigate active biological mechanisms in the cell and link them to the capacity to sustain or degrade the coherence of mechanical and optical degrees of freedom, hence exploring a practical interface betweem quantum science and biophysics.

Methods and techniques: Quantum optics, nanomechanics, biophysics, coherence

References:
[1] I. Favero and K. Karrai, Nat. Phot. 3, 201 (2009).
[2] E. Gil-Santos et al, Nature Nanotechnology 15 (6), 469-474 (2020).
[3] O. Alvar, et al. IEEE 36th International Conference on Micro Electro Mechanical Systems (MEMS 2023).

Contact: Ivan Favero

Methods and techniques: Quantum optics, nanomechanics, single-photon counting, low temperatures

References:
I. Favero and K. Karrai, Nat. Phot. 3, 201 (2009),
M. Aspelmeyer, T. Kippenberg and F. Marquardt, Rev. Mod. Phys. 86, 1391 (2014)
S. Barzanjeh, Nat. Phys. 10, 1038 (2021)
A. Barbero, S. Pautrel, …, A. Borne, I. Favero (2025).

Contacts: Adrien Borne, Ivan Favero

Left: scanning electron microscope image of an optomechanical disk resonator mechanically shielded from the environment (nanofabrication by our team). Right: theoretical Wigner function of a superposition Fock state.

The motion of massive, mesoscopic-scale mechanical resonators can behave quantum mechanically when cooled down to ultra-low temperatures. The exploration of such systems in the quantum regime has interests ranging from fundamental testing of quantum mechanics in mesoscopic massive objects to their use as quantum sensors, or in quantum networks, e.g. for transducing or storing the quantum information.

This project aims at shaping arbitrary target quantum states of motion [1] of an optomechanical resonator such as the microdisk pictured on the right and developed in our group. The mechanical quantum information can be encoded in the device through its interaction with light [2], and then characterized through optical tomographic reconstruction [3]. This work will also consider increasing the dimensionality by including several optomechanical resonators, thereby involving entanglement between massive objects.

Methods and techniques: Quantum optomechanics, single-photon counting, quantum state tomography, cryogenics

References:
[1] MR Vanner, M Aspelmeyer and MS Kim, PRL 110, 010504 (2013).
[2] I Favero and K Karrai, Nat. Phot. 3, 201 (2009). M Aspelmeyer, T Kippenberg and F Marquardt, Rev. Mod. Phys. 86, 1391 (2014).
[3] MR Vanner, I Pikovski, and MS Kim, Ann. Phys. 527 (2015).

Contact: Adrien Borne

Transducers in a quantum information network, linking microwave qubits nodes and silicon photonics

The development of quantum information technologies requires the interconnection of different quantum systems having specific tasks (processing, memory), such as microwave qubits platforms. Photons in the near-infrared allow for such efficient transfer of quantum information, preserving the non-classical state over long distances. The conversion of quantum information between microwave photons and optical photons is therefore a key step that this project aims to achieve.

The objective of this project is therefore to design a device to demonstrate the conversion of classical and then quantum signals between these two spectral domains. This on-chip converter will consist of a superconducting microwave resonator and an optical resonator, both interacting with a mechanical mode that will mediate the conversion. With these converters, we will then aim to generate entanglement between distant microwave qubits.

This project will be carried out in close collaboration with our partners in Grenoble: the Néel Institute, an expert in superconducting quantum circuits and electromechanics, and CEA Leti, one of Europe’s leading technological research organizations.

Methods and techniques: optomechanics, quantum interconnects, numerical simulations, nanofabrication, low temperatures.

Contacts: Ivan Favero, Adrien Borne