Bessel beam optical tweezers for manipulating superparamagnetic beads.

Area of Science:

• Physics
• Biotechnology
• Materials Science

Background:

• Optical tweezers are crucial for manipulating microscopic particles.
• Superparamagnetic beads are widely used in biophysics and nanotechnology.
• Trapping absorbing particles with optical tweezers presents challenges due to light absorption.

Purpose of the Study:

• To develop and characterize a Bessel beam optical tweezers setup for stable trapping of superparamagnetic beads.
• To investigate the influence of Bessel beam parameters and laser power on trap stiffness.
• To validate the experimental findings with a theoretical model incorporating spherical aberration and light absorption.

Main Methods:

• Utilized a Bessel beam optical tweezers setup.
• Experimentally measured trap stiffness for superparamagnetic beads.
• Varied Bessel beam radius and bead height.
• Investigated the effect of laser power on trap stiffness.
• Developed a geometrical optics model including spherical aberration and light absorption.

Main Results:

• Achieved stable trapping of superparamagnetic beads.
• Demonstrated that trap stiffness is largely independent of Bessel beam radius and bead height.
• Observed a linear increase in trap stiffness with laser power, even with significant bead absorption.
• The theoretical model showed excellent agreement with experimental data for optical forces and trap stiffness.

Conclusions:

• The Bessel beam optical tweezers system provides accurate and stable manipulation of absorbing magnetic particles.
• The findings advance the understanding of optical trapping for absorbing materials.
• This work paves the way for novel applications, such as hybrid optomagnetic tweezers.