Technique for rapid mass determination of airborne micro-particles based on release and recapture from an optical dipole force trap

Abstract

We describe a new method for the rapid determination of the mass of particles confined in a free-space optical dipole-force trap. The technique relies on direct imaging of drop-and-restore experiments without the need for a vacuum environment. In these experiments, the trapping light is rapidly shuttered with an acousto-optic modulator causing the particle to be released from and subsequently recaptured by the trapping force. The trajectories of both the falls and restorations, imaged using a high-speed CMOS sensor, are combined to determine the particle mass. We corroborate these measurements using an analysis of position autocorrelation functions of the trapped particles. We report a statistical uncertainty of less than 2% for masses on the order of $5\times 10^{-14}$ kg using a data acquisition time of approximately 90 seconds.

References in corpus (7)

• Parametric Resonance of Optically Trapped Aerosols
• High-resolution detection of Brownian motion for quantitative Optical Tweezers experiments
• Power Spectrum Analysis for Optical Tweezers, II: Laser Wavelength Dependence of Parasitic Filtering, and how to Achieve High Band-Width
• Development of a Fast Position-Sensitive Laser Beam Detector
• Simultaneous measurement of mass and rotation of trapped absorbing particles in air
• Photophoretic trampoline - Interaction of single airborne absorbing droplets with light
• Temporal dependence of optically-induced photophoretic force on absorbing airborne particles by a power-modulated laser