Deformable mirror-based photoacoustic remote sensing (PARS) microscopy for depth scanning

Area of Science:

• Biomedical Optics
• Microscopy
• Biophotonics

Background:

• Conventional microscopy often requires mechanical scanning for depth imaging, which can be detrimental to delicate biological samples.
• Photoacoustic Remote Sensing Microscopy (PARS) offers label-free imaging capabilities but traditionally lacks efficient axial scanning.
• Optical focal plane shifting presents a non-invasive alternative for depth visualization in biological imaging.

Purpose of the Study:

• To develop and demonstrate an optical method for axial scanning in PARS.
• To enable depth imaging of biological structures without physical sample manipulation.
• To advance label-free, non-contact microscopy techniques for biological research.

Main Methods:

• Integration of a deformable mirror as a varifocal element within a PARS system.
• Implementation of optical focal plane shifting for axial scanning (Δz ∼ 240 µm).
• System validation using USAF resolution targets and carbon fiber phantoms, followed by in-vivo imaging.

Main Results:

• Demonstrated successful optical focal plane shifting for depth scanning.
• Achieved axial scanning range of approximately 240 µm.
• Successfully visualized in-vivo blood vessels in chicken embryo chorioallantoic membrane (CAM).

Conclusions:

• The deformable mirror-based PARS system enables non-contact axial scanning.
• This technique is a promising step towards aberration-free, label-free PARS imaging with depth visualization.
• Further development could lead to advanced non-invasive imaging tools for delicate biological samples.