Multiphysics optomechanical sensing of a liquid on the micron scale

Area of Science:

• Optomechanics
• Microfluidics
• Materials Science

Background:

• Characterizing fluid properties at the microscale is crucial for various scientific and industrial applications.
• Existing methods often require larger sample volumes and longer measurement times.
• There is a need for compact, efficient platforms for in-situ fluid analysis.

Purpose of the Study:

• To develop and demonstrate an optomechanical device for comprehensive fluid property characterization.
• To enable rapid, low-power measurements of rheological, optical, and thermal properties.
• To validate the platform's performance using analytical models.

Main Methods:

• Utilized a suspended silicon microdisk resonator with a low vibrating mass (100 pg) and small probing volume (< 1 pL).
• Employed analytical models to interpret fluid-structure interactions, thermo-optical effects, and thermal diffusion.
• Integrated the microdisk resonator into a compact measurement setup for fluid analysis.

Main Results:

• Successfully determined viscosity, density, compressibility, refractive index, and thermal conductivity of fluids.
• Achieved single measurement times as short as 70 μs.
• Demonstrated low power consumption (< 100 μW), ensuring measurements at rest and in thermal equilibrium.

Conclusions:

• The developed optomechanical platform offers a highly sensitive and efficient method for microscale fluid characterization.
• The platform's speed, low power, and small sample volume requirements make it suitable for diverse applications.
• This technology advances the capability for detailed analysis of fluids in microfluidic systems.