An opto-thermal approach for rotating a trapped core-shell magnetic microparticle with patchy shell.

Area of Science:

• Physics
• Nanotechnology
• Biophysics

Background:

• Optical tweezers are limited in rotating magnetic particles due to light's spin angular momentum transfer constraints.
• Magnetic particle manipulation is crucial for biophysical research and developing optical micromachines.

Purpose of the Study:

• To propose a new method for controlled spin rotation of magnetic microparticles.
• To overcome the limitations of optical tweezers in achieving particle spin rotation.

Main Methods:

• Utilizing phoretic torque generated by inhomogeneous laser heating of the microparticle surface.
• Trapping and rotating magnetic microparticles near the laser focus center.

Main Results:

• Achieved controlled spin rotation of magnetic microparticles at frequencies of several Hertz.
• Demonstrated that rotation frequency can be tuned by adjusting laser power.

Conclusions:

• The proposed method offers a viable approach for controlled spin rotation of microscopic magnetic particles.
• This technique facilitates simultaneous translational and rotational manipulation of microparticles within a single optical trap.