Time-reversed magnetically controlled perturbation (TRMCP) optical focusing inside scattering media

Area of Science:

• Biomedical Optics
• Biophotonics
• Optical Engineering

Background:

• Focusing light deep within biological tissues is challenging due to light scattering.
• Optical wavefront engineering requires an internal guidestar for feedback and precise targeting.
• Existing guidestar methods include fluorescent probes, ultrasonic modulation, and absorption perturbation.

Purpose of the Study:

• To propose and demonstrate a magnetically controlled optical absorbing microsphere as an internal guidestar for light focusing.
• To achieve dynamic optical focusing within scattering media using digital optical phase conjugation.
• To explore potential applications in targeted drug delivery and tumor treatment.

Main Methods:

• Utilized a digital optical phase conjugation system.
• Employed a magnetically controlled optical absorbing microsphere as the internal guidestar.
• Time-reversed scattered light perturbed by the microsphere to achieve constructive interference at the target.

Main Results:

• Achieved sharp optical focusing within scattering media.
• Demonstrated dynamic optical focusing by magnetically controlling the microsphere, allowing for a large field-of-view.
• Showcased the microsphere's potential for integration with biological carriers.

Conclusions:

• The magnetically controlled microsphere guidestar enables precise and dynamic light focusing in scattering media.
• This technique offers a promising platform for advanced biomedical applications, including targeted therapies and diagnostics.
• The magnetic control allows for external manipulation and broad applicability in complex biological environments.