Post-Doc

Quantum logic operations depend on the operation of both one quantum information bit (qubit) and two-qubit gates requiring the coherent interaction between pairs of qubits. For quantum communication and computing applications it is advantageous to integrate many qubits on a single chip. The discrete density of states of semiconductor Quantum Dots (QDs) and their ease of integration into conventional semiconductor device structures makes them ideal for quantum information processing applications ranging from single photon sources to spin qubit manipulation.

In this project we will develop a two qubit integrated device for quantum information processing. This device will be be based on In(Ga)As QDs deterministically placed in specific locations in a photonic crystal. The objective is to demonstrate a scalable design of a two qu-bit gate based on on-chip optically connected spin-qubits.

The post-doc will be involved in the design and growth optimisation of QD heterostructures, working with Paola ATKINSON at INSP (Paris) and in the fabrication of photonic structures in Rémy BRAIVE’s team at C2N (Palaiseau). The post-doc will work closely with the quantum optics group at the INSP (Paris) where the optical measurements of the photonic QD devices will be carried out. She/He has to have demonstrated skills in growth and clean-room techniques. She/He should have a good knowledge of the physics of quantum dots and photonic crystals. Some background in low temperature optical measurements would be greatly appreciated.

Post-Doc

Light-matter interaction at the single-quanta level is the keystone of quantum information science. However, single quanta are generally weakly interacting and enhancing this coupling has been the driving force for a large community and the development of the cavity quantum electrodynamics (CQED) [1], where single atoms and single photons can be strongly coupled via a high-finesse cavity. The resulting controllable coupling led to a better understanding of fundamental aspects of light-matter interaction and to various seminal demonstrations.

Very recently, integrated photonic nanostructures appeared as a promising avenue of tailoring light-matter interaction by engineering the emitter environment. Modern nanofabrication techniques have indeed enabled to design solid-state systems with embedded emitters, such as quantum dots in photonic crystal waveguides or in nanocavities with high-quality factors, leading to Quantum Nanophotonics. In this context, we explore the waveguide QED approach by trapping atoms close to photonic crystal waveguides exhibiting slowly propagating modes, reaching strong interaction without a cavity.

A post-doctoral position is open in the TONIQ group [2] at C2N for a young scientist. C2N is a research unit of CNRS and University Paris-Sud. Its objectives are to establish a flagship laboratory for research in nanoscience and nanotechnology and to provide a large technology facility in Paris region, open to academic and industrial players in the field.

The main aim of the project is the optimization of the slow mode propagating in nanowaveguides for both achieving strong coupling with single atoms and engineering of the collective response in mesoscopic populations, making strong atom-atom interaction mediated by the slow mode possible. The applicant will have to design and simulate photonic crystal waveguides in order to exhibit slow modes at 780 nm, the resonance wavelength of rubidium atoms. She or He will contribute to the different steps of the fabrication process in the 2800 m2 cleanroom facility of C2N, which is one of the largest in France. She or He will participate in the optical experiments to characterize the performance of the fabricated slow mode waveguides and will collaborate with Julien Laurat’s team [3] at LKB (Jussieu) in the atomic experiment.

Candidate profile: The applicant should have good skills in optics and nonlinear optics. Knowledge in cold atom physics, although not mandatory, will be appreciated. She/He should be motivated to perform photonic crystal numerical simulation designs and to participate in the fabrication process. Good teamwork skills will be essential to optimally link the two research teams and for productive interaction with the cleanroom facility engineers.

Funding: The postdoctoral position will be funded by the laboratory of excellence in nanoscience and nanotechnology, Labex NonoSaclay, through the flagship project IQOQCS.

Duration: The duration of the postdoctoral position is 18 months, with a possibility of extension.

References : 

[1] S. Haroche and J.M. Raimond, Exploring the quantum: atoms, cavities and photons (Oxford Univ. Press, 2006).

[2] V. Huet et. al., Millisecond photon lifetime in a slow-light microcavity, Phys. Rev. Lett. 116, 133902 (2016); Ph. Hamel, et.al., Coupling light into slow-light photonic-crystal waveguide ..., Opt. Express 21, 15144 (2013).

[3] N.V. Corzo, J. Raskop, A. Chandra, A.S. Sheremet, B. Gouraud, J. Laurat, Waveguide-coupled single collective excitation of atomic arrays, Nature 566, 359 (2019).