Séminaire

Mardi 8 Novembre 2016 à 11h00.

Hybrid Light-Matter-Nano-mechanics systems

''Light-matter interaction plays a prominent role in quantum physics since its early stages, and Cavity-Quantum Electrodynamics (CQED) especially in the last 30 years. Optomechnanics at the nano-scale very recently enters the game allowing for the observation of the quantum ground state of mesoscopic oscillators. By combining these two fields : meaning a quantum emitter coupled to a nano-oscillator, hybrid systems aim at bringing quantum mechanics at a larger scale to study for example decoherence phenomenon on a large number of atoms or the quantum/classical border. I will present three different experiments I performed in the vast field of light-matter mechanics interaction. I will first discuss my PhD results focused on the coupling of cavity photons with semiconductor excitons. I will describe how one can make a very good mirror at the end of an optical fibre to form a high finesse tunable Fabry-Pérot cavity and I will present the result of its coupling with a quantum dot [1] and quantum wells [2]. Then, I will present one way to probe the effect of artificial atoms (NV center) on the mechanical properties of a nano-diamond trapped by optical tweezers in liquid [3]. Finally I will introduce a hybrid system where the mechanical oscillator is a single clamped nano-wire with a quantum emitter attached at its free extremity. I will focus on the opto-mechanical part to show how this system can be used as a force sensor [4] from room temperature to dilution fridge temperature reaching state of the art force sensitivity (10−20 N.Hz−1/2). [1] Cavity quantum electrodynamics with charge-controlled quantum dots coupled to a fiber Fabry Perot cavity, J. Miguel-Sánchez, et al. New. J. Phys.15, 045002 (2013). [2] Polariton boxes in a tunable fiber cavity, B. Besga, et al. Phys. Rev. Applied3, 014008 (2015). [3] Cooperatively-enhanced dipole forces from artificial atoms in trapped nanodiamonds, M.L. Juan, et al. accepted in Nat. Phys. (2016). [4] A universal and ultrasensitive vectorial nanomechanical sensor for imaging 2D force fields, L. Mercier de Lépinay, et al. accepted in Nat. Nanotech. (2016).''