Device and method for measuring property of a fluid

{
  "publication_number": "US2026104351A1",
  "country": "US",
  "kind": "A1",
  "title": "Device and method for measuring property of a fluid",
  "abstract": "A device for measuring at least one property of a fluid, including a cell (1) adapted to receive a volume of fluid, an optical waveguide (2) including an input port (20) adapted to be coupled to a light source (3) so as to transmit an optical signal (L) emitted by the light source, an optomechanical resonator (7) arranged in the cell (1) so as to have at least one main surface in contact with the fluid, the resonator including a suspended element (70) arranged in the vicinity of the optical waveguide (2) so as to allow evanescent coupling between the optical waveguide (2) and the suspended element (70), a measuring unit (5) arranged at an output port (21) of the optical waveguide (2) for receiving the output optical signal, and a processing unit coupled to the measuring unit.",
  "claims": [
    "1. 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. 2. The device of claim 1, wherein the suspended element is a disc or a ring secured to a substrate defining one face of the cell by a central foot. 3. The device of claim 1, wherein the suspended element has an oblong shape and is secured to a substrate defining one face of the cell by two feet. 4. The device of claim 1, wherein the suspended element is a nanostructured beam secured by its two ends to a substrate defining two faces of the cell. 5. The device of claim 1, wherein the suspended element is made of an optomechanical crystal, in particular silicon. 6. The device of claim 1, wherein the cell has a volume of less than 1 microliter, preferably less than 1 nanoliter. 7. The device of claim 1, wherein the cell has at least one dimension less than 1 mm, preferably less than 200 μm. 8. The device of claim 1, wherein the cell is closed. 9. The device of claim 1, wherein the cell is a microfluidic channel extending between a fluid inlet and a fluid outlet. 10. The device of claim 1, further comprising at least one actuation device adapted to vibrate the suspended element. 11. The device of claim 1, further comprising a heater for controlling the temperature of the fluid in the cell. 12. A method for measuring at least a first property and a second property of a fluid, comprising: placing the fluid in the cell of a device according to claim 1, transmitting an optical signal emitted by the light source by the optical waveguide, exciting at least one optical mode of the optomechanical resonator by the evanescent coupling of the suspended element and the optical waveguide, oscillating the suspended element according to at least one mechanical resonance mode, said oscillation affecting the signal transmitted by the optical waveguide by the evanescent coupling, measuring, by the first detection unit, a low-frequency component of the output signal, measuring, by the second detection unit, a radiofrequency component of the output signal, from measurement data of the first detection unit, determining the first property among a refractive index and a thermal conductivity of the fluid, from measurement data of the second detection unit, determining the second property among a viscosity, a density and a compressibility of the fluid. 13. The method of claim 12, wherein the cell is closed and the fluid is static in the cell. 14. The method of claim 12, wherein the cell is a microfluidic channel extending between a fluid inlet and a fluid outlet and the fluid is flowing in the microfluidic channel. 15. The method of claim 12, comprising a power sweep of the light source. 16. The method of claim 12, comprising a wavelength sweep of the light source. 17. The method of claim 12, wherein the device comprises at least one actuation device adapted to vibrate the suspended element, the method further comprising activating the at least one actuation device to vibrate the suspended element, and wherein the detection unit measures a resonance frequency of the suspended element. 18. The method of claim 12, wherein the suspended element is activated in vibration by thermomechanical noise generated by molecules of the fluid, and wherein the detection device measures a resonance frequency of the suspended element. 19. The method of claim 12, comprising simultaneously transmitting, by the optical waveguide, two light beams of different wavelengths, each wavelength being associated with a measurement of a low frequency, respectively radio frequency component, of the output signal, and simultaneously measuring said components by the first and second detection units."
  ],
  "description_excerpt": "The invention relates to a device for measuring properties of a fluid, as well as a measuring method implemented by means of said device.\n\nThere are different techniques for characterizing a fluid, based on different properties and different measurement means.\n\nFor example, in the laboratory there are different types of viscometers or rheometers to measure the viscosity of a fluid. However, each apparatus is optimized for a specific type of fluid, so it may be necessary to have different apparatuses to cover a wide range of fluids.\n\nMoreover, these devices only measure viscosity and other devices must therefore be used if other properties of the fluid, such as its density, refractive index or thermal conductivity, are to be determined.\n\nFinally, laboratory viscometers and rheometers are designed to receive samples of a relatively large volume.\n\nHowever, in the field of diagnostics, significant needs are associated with “point of care” type tests, that is to say tests carried out close to the patient. These tests must be able to be implemented by personnel not necessarily trained in laboratory medicine and therefore require compact and easy-to-use devices.\n\nLaboratory apparatuses are not suitable for this type of use.\n\nThere is therefore a need for a measurement device suitable for small fluid samples and capable of determining different properties of the latter.\n\nThe invention aims at overcoming the aforementioned problems and to propose a measurement device capable of analyzing samples on the scale of a few microliters with great precision while being able to determine several different properties of the fluid.",
  "cpc": [
    "G01N 21/1702",
    "G01N 2201/0231",
    "G01N 2201/08"
  ],
  "ipc": [
    "G01N 21/17"
  ],
  "assignees": [
    "Centre National de la Recherche Scientifique CNRS",
    "Commissariat a lEnergie Atomique et aux Energies Alternatives CEA",
    "Universite Paris Cite"
  ],
  "inventors": [
    "Guillaume JOURDAN",
    "Hamidreza NESHATEH",
    "Ivan Favero"
  ],
  "filing_date": "2025-10-15",
  "publication_date": "2026-04-16",
  "priority_date": "2024-10-16",
  "application_number": "US-202519358786-A",
  "family_id": "94081043",
  "cited_by_count": 0
}