Label-free multiphoton microscopy with a visible femtosecond laser

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Materials Science

Background:

• Multi-photon microscopy (MPM) typically uses near-infrared lasers.
• Visible femtosecond lasers offer higher photon energy for broader fluorophore excitation.
• Enhanced excitation is crucial for label-free imaging of biological and material samples.

Purpose of the Study:

• To design and construct a novel multi-photon microscope.
• To utilize a home-built green femtosecond laser as the excitation source.
• To demonstrate improved spatial resolution and label-free imaging capabilities.

Main Methods:

• Construction of a multi-photon microscope system.
• Integration of a home-built green femtosecond laser.
• Testing with biological tissues and microplastic samples.
• Demonstration of UV two-photon fluorescence and deep-UV second harmonic generation (SHG) detection.

Main Results:

• Achieved a two to threefold improvement in spatial resolution.
• Reached a lateral resolution of 172 nm.
• Successfully performed label-free imaging of human cancerous pancreatic tissue.
• Detected nano-micro plastics in bottled water using label-free imaging.

Conclusions:

• Visible femtosecond lasers significantly enhance MPM spatial resolution and imaging versatility.
• The developed system offers high-resolution, label-free imaging for diverse applications.
• This technology advances the analysis of biological samples and environmental contaminants.