Precession Motion in Levitated Optomechanics.

Area of Science:

• Experimental physics
• Nanoparticle dynamics
• Optomechanics

Background:

• Levitated nanoparticles offer a unique platform for studying fundamental physics in a controlled environment.
• Understanding nanoparticle dynamics is crucial for applications in sensing and metrology.

Purpose of the Study:

• To experimentally investigate the dynamics of a nonspherical levitated nanoparticle in a vacuum.
• To develop and validate a theoretical model for light torque-induced motion.
• To measure torque and torque sensitivity in levitated nanoparticles.

Main Methods:

• Experimental setup for trapping and observing nonspherical nanoparticles in vacuum.
• Development of a theoretical model incorporating translation, rotation, precession, and nutation.
• Numerical simulations of the theoretical model.
• Experimental measurements of torque and torque sensitivity at different pressures.

Main Results:

• Observation of light torque-induced precession and nutation in nonspherical levitated nanoparticles.
• Theoretical model and numerical simulations show good agreement with experimental observations.
• Measured torque of 1.9±0.5×10⁻²³ N m at 1×10⁻¹ mbar.
• Estimated torque sensitivity of 3.6±1.1×10⁻³¹ N m/√Hz at 1×10⁻⁷ mbar.

Conclusions:

• The study successfully models and experimentally verifies the complex dynamics of nonspherical levitated nanoparticles under light torque.
• The findings provide insights into optomechanical forces acting on non-spherical particles.
• The achieved torque sensitivity demonstrates potential for high-precision measurements.