Optomechanical transduction system with improved detection

An optomechanical system for transducing an optical phase shift movement comprising:

• a mechanical sensor comprising a mobile mass of which a surface, called receiving surface, is intended to receive one or more particle(s) to be detected and to undergo the weight of the particle(s) to be detected, and an excitation device,
• an optical detector comprising an optical resonator, the excitation device being configured to vibrate the mobile mass along a first direction called excitation direction (Y) at at least one of its resonance frequencies, the vibration of the mobile mass being modified by the weight of the particle(s) to be detected, the vibration of the mobile mass modifying an evanescent field of the optical detector,
• the mobile mass having a first region called interaction region facing the optical resonator of the optical detector,
• wherein the mobile mass comprises at least one second region located outside of the interaction region, the second region and the optical resonator located on either side of the interaction region, the interaction region and the second region respectively having, projecting along a plane perpendicular to the excitation direction (Y), called vertical plane (XZ), an interaction surface area Sin and a second surface area S112, the second region being such that S111>S112, and in that along a third direction (Z) perpendicular to a plane, called excitation plane (XY), parallel to which the receiving surface mainly extends, the interaction region has a height H111 and the second region has a height H112, with H111>H112.