Multiphoton and Harmonic Imaging of Microarchitected Materials

Area of Science:

• Microfabrication and Advanced Imaging
• Materials Science and Engineering

Background:

• Microadditive manufacturing produces intricate nano- to microscale components.
• Multiphoton lithography (MPL) is a key technique for fabricating these complex structures.

Purpose of the Study:

• To evaluate two-photon (2P), three-photon (3P) fluorescence imaging, and third-harmonic generation (THG) microscopy for analyzing MPL-fabricated microstructures.
• To demonstrate the capability of these techniques for non-destructive defect detection and quality control.

Main Methods:

• Fabrication of periodic microarchitected lattice structures using MPL.
• High-fidelity 3D imaging using 2P and 3P fluorescence microscopy and THG microscopy.
• Utilizing refractive index matching fluids to enhance imaging depth and clarity.

Main Results:

• Achieved high-fidelity 3D reconstructions of both fluorescent and low-fluorescence microstructures.
• Demonstrated reduced signal decay with depth for multiphoton fluorescence (MPF) imaging compared to single-photon methods.
• Successfully identified internal modifications and compression-induced fractures non-destructively.

Conclusions:

• MPF imaging offers superior depth penetration for microadditively manufactured components.
• 2P, 3P, and THG microscopy are powerful tools for quality control and defect analysis in microfabrication.
• These advanced imaging techniques are crucial for ensuring the integrity of complex microscale components.