We are developing mechanical sensors, in the form of Silicon carbide nanowires, with atto (10 -18 ) to zepto (10 -21 ) Newton force sensitivity [1,2]. These mechanical oscillators are sensitive enough to measure the radiation pressure force of a light field and even reveal its quantum fluctuations.
In a first experiment, a nanowire is inserted in a small volume optical Fabry-Pérot cavity thus enhancing strongly the opto-mechanical interactions. By scanning a nanowire inside the cavity mode, we could map the optomechanical coupling and the reciprocal force applied on the sensor. Reaching the ultra-strong coupling regime allows measuring the force of a single intra-cavity photon [3].
In a second experiment, we mapped the electrostatic force between a nanowire and a nano-structured gold surface. By Compensating the electrostatic force with control electrodes, we are able to map the residual force coming from the electromagnetic field quantum fluctuations, or Casimir force, with very high resolution.
[1] A universal and ultrasensitive vectorial nanomechanical sensor for imaging 2D force fields, L. Mercier de Lépinay, B. Pigeau, B. Besga, ,P. Vincent, P. Poncharal and O. Arcizet, Nature Nanotechnology 11, (2016)
[2] Ultrasensitive nano-optomechanical force sensor operated at dilution temperatures.F. Fogliano, B. Besga, A. Reigue, L. Mercier de Lépinay, P. Heringlake, C. Gouriou, E. Eyraud, W. Wernsdorfer, B. Pigeau O. Arcizet , Nature Communications 12, 4124 (2021)
[3 ] Mapping the cavity optomechanical interaction with subwavelength-sized ultrasensitive nanomechanical force sensors. F. Fogliano, B. Besga, A. Reigue, P. Heringlake, L. Mercier de Lépinay, C. Vaneph, J. Reichel, B. Pigeau, and O. Arcizet, Phys. Rev. X 11, 021009 (2021)