Sub-acoustic resolution optical focusing through scattering using photoacoustic fluctuation guided wavefront shaping

Area of Science:

• Biomedical Optics
• Photoacoustics
• Wavefront Shaping

Background:

• Wavefront shaping requires noninvasive guide stars for focusing light through turbid media.
• Existing methods often rely on invasive or less sensitive feedback mechanisms.

Purpose of the Study:

• To introduce a photoacoustic guide star for wavefront shaping through scattering media.
• To demonstrate sub-acoustic resolution optical focusing using this novel technique.

Main Methods:

• Utilized fluctuations in photoacoustic signals from flowing absorbers in a micro-vessel as a feedback signal.
• Employed the standard deviation of photoacoustic signals, which increases nonlinearly with decreased illumination volume.
• Implemented a genetic algorithm for wavefront optimization.

Main Results:

• Successfully guided wavefront shaping using the photoacoustic signal standard deviation.
• Achieved sub-acoustic resolution optical focusing through a diffuser.
• Demonstrated the efficacy of the photoacoustic guide star in scattering environments.

Conclusions:

• The photoacoustic guide star offers a noninvasive and effective feedback mechanism for wavefront shaping.
• This technique advances optical focusing capabilities in scattering media.
• Potential applications in biomedical imaging and microscopy.