Revisit on dynamic radiation forces induced by pulsed Gaussian beams

Area of Science:

• Optical physics
• Nanotechnology
• Laser-matter interactions

Background:

• Recent advancements in ultra-short pulsed laser experiments for optical trapping.
• Existing models for pulsed radiation force (PRF) on dielectric spheres.

Purpose of the Study:

• Re-investigate optical trapping effects of PRF on Rayleigh dielectric spheres.
• Analyze the influence of transverse and axial PRFs on particle dynamics.
• Determine the impact of pulse duration on trapping dimensionality and stability.

Main Methods:

• Theoretical modeling based on a previous established model.
• Consideration of both transverse and axial components of PRF.
• Analysis of particle velocities and displacements within a pulse duration.

Main Results:

• Small Rayleigh particles: 3D trapping with long pulses, 2D trapping with short pulses (axial movement).
• Stable trapping (independent of pulse duration) achieved in vacuum or with weak Brownian motion due to cumulative momentum transfer.
• Large Rayleigh particles: Only 2D optical trapping (optical guiding) is predicted.

Conclusions:

• Pulse duration significantly influences the dimensionality of optical trapping for small Rayleigh particles.
• Cumulative momentum transfer enables stable, pulse-duration-independent trapping in low-dissipation environments.
• Results offer crucial insights into the trapping mechanisms of pulsed tweezers for various particle sizes.