Published the Oct. 25, 2021

A mechanical frequency comb with an atomically thin material

By efficiently coupling nanoresonators, made up of suspended 2D semiconductor membranes, with an optomechanical platform, physicists from the Center for Nanosciences and Nanotechnologies (C2N, Université Paris-Saclay / CNRS), in collaboration with researchers from Pennsylvania, produced a coherent mechanical frequency comb having a very large number of harmonics.

We study the mechanical vibrations of innovative materials such as atomically thin 2D materials that are only one nanometer thick. This ultra-thin sheet resonates like a drum, and its resonant frequency is exceptionally adjustable for a nano-object, as a nanoscale guitar string. Taking advantage of this property, we simultaneously measured and adjusted the vibration of 2D materials with electrical and optical excitation techniques. We have coupled the mechanical vibration ω1, to an electrical signal of frequency ωp. We obtain an artistic figure in the form of a checkerboard (on the left), which represents the comb of frequency ω1 ± m ωp and which contains up to m=100 harmonics and corresponding to the theoretical model (figure on the right). Potential applications are quantum information processing and heat transport
The technology used is an optomechanical measurement, the mechanical vibration is measured by the reflection of a laser on the sample and the mechanical movement is activated by an electronic signal and a capacitive coupling.
The mat2D group at C2N ( is expert in the electronic properties of 2D materials (Graphene, MX and MX2) Our activities focus on the design, manufacture and electronic properties of new hybrid heterostructures based on two-dimensional materials, with a view to the realization of a new generation of nanoelectronic devices. This publication is produced in collaboration with the University of Pennsylvania

Anis Chiout1, Franck Correia1, Meng-Qiang Zhao2,3, A.T. Charlie Johnson3, Debora Pierucci1, Fabrice Oehler1, Abdelkarim Ouerghi1, Julien Chaste1
Multi-order phononic frequency comb generation within a MoS2 electromechanical resonator.
Applied Review Letters, 119 (17), 173102

1) Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France.
2) Department of Physics and Astronomy, University of Pennsylvania, 209S 33rd Street, Philadelphia, Pennsylvania 19104 6396, United States
3) Department of Chemical and Materials Engineering, New Jersey Institute of Technology, 138 Warren Street, Newark, New Jersey 07103, United States

Figure : (left) Frequency comb appearing during the measurement of mechanical resonance as a function of the frequencies fD of the drive and fP of the pump (right) Strong coupling model between the mechanical resonance and the harmonics of the electronic signal. (bottom) Schematic of the device.