Device and method for measuring property of a fluid

A device for measuring a first property and a second property of a fluid, comprising:

• a cell adapted to receive a volume of fluid,
• an optical waveguide comprising an input port adapted to be coupled to a light source so as to transmit an optical signal emitted by the light source,
• an optomechanical resonator arranged in the cell so as to have at least one main surface in contact with the fluid, the resonator comprising a suspended element arranged in the vicinity of the optical waveguide to allow evanescent coupling between the optical waveguide and the suspended element,
• a measuring unit arranged at an output port of the optical waveguide for receiving the output optical signal, comprising:
• a first detection unit configured to measure a low frequency component of the output signal, and
• a second detection unit for measuring a radiofrequency component of the output signal, and
• a processing unit coupled to the measuring unit and configured to:
• from measurement data of the first detection unit, determine the first property of the fluid among a refractive index and a thermal conductivity of the fluid, and
• from measurement data of the second detection unit, determine the second property of the fluid among a viscosity, a density and a compressibility of the fluid.