Computation of the optical trapping force using an FDTD based technique.

Area of Science:

• Computational physics
• Optics
• Nanotechnology

Background:

• Optical radiation pressure is crucial for manipulating micro/nano-objects.
• Accurate computation of these forces is essential for designing optical trapping systems.
• Existing computational methods may have limitations in certain regimes.

Purpose of the Study:

• To present a 2-D Finite-Difference Time-Domain (FDTD) algorithm for computing optical radiation pressure force.
• To validate the algorithm's accuracy against experimental results and other computational techniques.
• To demonstrate the algorithm's applicability to various object geometries and dielectric properties.

Main Methods:

• Utilizing a 2-D grid FDTD algorithm to simulate electromagnetic field propagation.
• Calculating optical forces by analyzing changes in optical energy flow with and without objects.
• Applying the method to dielectric discs and thin-walled shells.

Main Results:

• The FDTD algorithm accurately computes optical radiation pressure forces.
• Predicted object behavior aligns with published experimental data and alternative computational methods.
• Demonstrated results for high and low dielectric constant discs and shells.

Conclusions:

• The FDTD technique provides a reliable method for computing light-particle force interactions across various scales.
• The algorithm is versatile and can be extended to 3-D simulations and torque computations.
• This flexible computational engine has broad applicability in optics and nanotechnology.