Single-shot linear dichroism optical-resolution photoacoustic microscopy

Area of Science:

• Biomedical Optics
• Photoacoustic Imaging
• Materials Science

Background:

• Dichroism describes how materials interact differently with light of varying polarizations.
• This property is linked to molecular composition and structure, offering potential for tissue differentiation.
• Existing methods may lack speed or precision in capturing dichroic information.

Purpose of the Study:

• To develop and demonstrate a single-shot dichroism photoacoustic microscopy (DPAM) technique.
• To enable simultaneous imaging of tissue structure, linear dichroism, and polarization angle.
• To enhance the speed and reduce noise in dichroic imaging.

Main Methods:

• A fiber-based laser system generates three synchronized pulses with distinct polarization angles.
• A dual-fiber optical-resolution photoacoustic microscopy system acquires data from these pulses.
• Single raster scanning captures multiple data types, including dichroism.

Main Results:

• The DPAM technique achieves imaging speeds comparable to single-wavelength photoacoustic microscopy.
• Utilizing a single laser pulse for all polarizations reduces energy fluctuations and measurement noise by approximately 35%.
• The system successfully images endogenous and exogenous polarization-dependent absorption contrasts.

Conclusions:

• Single-shot DPAM offers a fast and robust method for imaging dichroic properties in tissues.
• This technique can visualize molecular orientation and distribution, aiding in the detection of conditions like tumors.
• DPAM holds promise for enhanced biomedical imaging and diagnostics.