Nanothermometry in rarefied gas using optically levitated nanodiamonds.

Area of Science:

• Thermodynamics
• Fluid Dynamics
• Nanotechnology

Background:

• Fourier's law accurately describes heat transfer in continuum gases.
• In rarefied gas regimes, Fourier's law is insufficient, necessitating advanced models.
• Experimental validation of heat transfer models in spherical geometries is challenging.

Purpose of the Study:

• To investigate heat transfer mechanisms in rarefied gases using a novel experimental approach.
• To explore the limitations of continuum heat transfer models in subcontinuum regimes.
• To demonstrate the efficacy of optically levitated nanoparticles for gas-phase heat transfer studies.

Main Methods:

• Utilizing optically levitated nanodiamonds with nitrogen-vacancy centers for precise temperature measurements.
• Conducting experiments across a wide range of gas pressures to observe heat transfer variations.
• Employing nanodiamonds as isolated systems to minimize environmental interference.

Main Results:

• Observed a significant increase in nanodiamond temperature (over 200 K) as gas pressure decreased.
• Demonstrated a direct correlation between reduced gas pressure and diminished heat transfer.
• Confirmed the viability of optically levitated nanoparticles for studying heat transfer in diverse gas environments.

Conclusions:

• Optically levitated nanoparticles provide an ideal platform for studying rarefied gas heat transfer.
• Experimental data obtained can be integrated with theoretical models to determine energy accommodation coefficients.
• This technique offers a versatile method for characterizing gas-phase heat transfer across various pressures.