Frequency-swept time-reversed ultrasonically encoded optical focusing.

Area of Science:

• Biomedical Optics
• Acousto-Optics
• Medical Imaging

Background:

• Optical focusing in turbid media is crucial for biomedical applications.
• Time-reversed ultrasonically encoded (TRUE) optical focusing enables light penetration through scattering media.
• Previous digital TRUE focusing methods were time-consuming for scanning.

Purpose of the Study:

• To accelerate the scanning of TRUE optical foci within turbid media.
• To demonstrate a multiplex recording technique for faster TRUE focus generation.
• To improve the efficiency of optical focusing for biomedical imaging.

Main Methods:

• Multiplex recording of ultrasonically encoded wavefronts by sweeping ultrasound and light frequencies.
• Utilizing digital TRUE optical focusing principles.
• Imaging a fluorescent target within a 2.4 transport mean free path thick turbid sample.

Main Results:

• Successfully demonstrated accelerated generation of multiple TRUE foci.
• Achieved a 2-D image of a fluorescent target embedded in a highly scattering medium.
• Significantly reduced the time required for scanning the TRUE focus.

Conclusions:

• The developed multiplex recording technique substantially accelerates TRUE optical focusing.
• This advancement offers a more efficient method for optical imaging in scattering biological tissues.
• The technique shows promise for various real-time biomedical diagnostic and therapeutic applications.