Optomechanical Cristal coupled to a SAW for microwave to infrared transduction

Published : 8 February 2020

The most promising quantum computing platforms today are operated at very low temperatures at microwave frequencies, while telecommunication networks capable of preserving information in unconventional states (superposition, entanglement) use infrared (IR) photons at room temperature. Current frequency conversion means offer poor conversion efficiencies (10-6), which make them unusable for processing quantum information. A very highly efficient optical microwave converter is an essential step in linking these two frequency domains and creating a genuine network of distributed quantum computers (quantum internet). The proposed thesis topic aims to develop such a converter by exploiting the multi-scale coupling properties of mechanical nanoresonators.

The first technological bricks have recently been produced with coupled mechanical/IR or mechanical/microwave systems in quantum regime. The aim here is to design an optomechanical crystal coupled to an IR resonator. The optomechanical crystal operating at microwave frequencies (GHz) will be actuated with the help of a SAW (Acoustic Wave Surface) powered by a microwave wave. This type of system offers a very low rate of insertion of conventional noise into the conversion process.

The AlN deposition will be carried out in Leti’s clean room, and then the subsequent steps can be continued at the PTA (academic clean room) which offers more flexibility in terms of the manufacturing process. A collaboration is in place with the Néel Institute (CNRS) in Grenoble to characterize these ultra-low temperature (<100mK) devices. This will allow the devices to be tested and compared with the expected performance. It will then be necessary to review the modelling and design based on the measurements in order to ensure that all phenomena are understood.

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