Collecting optical coherence elastography depth profiles with a micromachined cantilever probe

Area of Science:

• Biophysics
• Materials Science
• Medical Imaging

Background:

• Characterizing subsurface mechanical properties is crucial for understanding material behavior and biological tissue function.
• Existing techniques often lack the resolution or depth penetration required for comprehensive analysis.

Purpose of the Study:

• To present a novel experimental setup integrating optical coherence elastography (OCE) depth sensing with atomic force microscopy (AFM) indentation.
• To enable high-resolution, in-situ measurement of subsurface layer deformation under controlled indentation forces.

Main Methods:

• A miniaturized cantilever probe performs localized force application on the sample surface.
• Simultaneous depth profiling is achieved using optical coherence tomography (OCT) beneath the indentation point.
• Cantilever deflection is monitored via optical fiber interferometry (2 nm resolution), and OCT provides subsurface deformation profiles (15 nm resolution, millimeter depth range).

Main Results:

• The combined OCE-AFM system successfully measures sample deformation with high spatial and depth resolution.
• Demonstrated capability for nanoscale precision in quantifying subsurface mechanical responses.
• Achieved a depth range of a few millimeters for deformation profiling.

Conclusions:

• This integrated approach offers a powerful tool for advanced material characterization and biomechanical studies.
• The system provides unprecedented insights into the mechanical properties of materials and biological tissues at the subsurface level.