Interferometric backward third harmonic generation microscopy for axial imaging with accuracy beyond the diffraction...

Area of Science:

• Nonlinear optics
• Microscopy
• Nanotechnology

Background:

• Accurate measurement of nanoscale variations is crucial in materials science and biology.
• Existing microscopy techniques face limitations in resolution and accuracy for certain applications.

Purpose of the Study:

• To introduce a new nonlinear microscopy technique for high-accuracy height and thickness measurements.
• To demonstrate the technique's capability in visualizing fine surface and layer variations.

Main Methods:

• Development of an interferometric technique utilizing backward-reflected third harmonic generation (I-THG) from multiple interfaces.
• Application of the I-THG microscope for imaging patterned glass surfaces and fibroblast cell thickness.

Main Results:

• Achieved measurement accuracy of up to 5 nm for height variations and layer thickness.
• Visualized height variations with accuracy exceeding the diffraction limit by two orders of magnitude.
• Demonstrated visualization of thickness variations in fibroblasts.

Conclusions:

• The I-THG microscopy technique offers unprecedented accuracy for nanoscale measurements.
• This method has broad applications in biological tissue imaging and surface analysis.
• The technique surpasses the diffraction limit for precise distance variation measurements.