Selected Publications

Beyond linear coupling in microwave optomechanics

D. Cattiaux, X. Zhou, S. Kumar, I. Golokolenov, R. R. Gazizulin, A. Luck, L. Mercier de Lépinay, M. Sillanpää, A. D. Armour, A. Fefferman, E. Collin

We explore the nonlinear dynamics of a microwave optomechanical system consisting of a drumhead nano-electro-mechanical resonator (NEMS) capacitively coupled to a microwave cavity. Experiments are performed under a strong microwave Stokes pumping which triggers mechanical self-sustained oscillations. We analyze the results in the framework of an extended nonlinear optomechanical theory, and demonstrate that quadratic and cubic coupling terms in the opto-mechanical Hamiltonian have to be considered. Quantitative agreement with the measurements is obtained considering only genuine geometrical nonlinearities: no thermo-optical instabilities are observed, in contrast with laser-driven systems. Based on these results, we describe a method to quantify nonlinear properties of microwave optomechanical systems. This method is clearly a new technique available in the quantum electro-mechanics toolbox, where higher-order coupling terms are proposed as a new resource for specific quantum schemes like quantum non-demolition (QND) measurements. We also find that the motion imprints a wide comb of extremely narrow peaks in the microwave output field, which could also be exploited in specific microwave-based measurements, potentially limited only by the quantum noise of the optical {\it and} the mechanical fields for a ground-state cooled NEMS device.