Coherent scattering in multi-harmonic light microscopy

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Microscopy

Background:

• Multi-photon excited fluorescence microscopy is a well-established imaging technique.
• Harmonic up-conversion and multi-photon excited fluorescence can be generated using pulsed laser beams.
• The application of multi-harmonic generation for 3D image contrast is a recent development.

Purpose of the Study:

• To introduce and explore the potential of multi-harmonic generation microscopy.
• To compare multi-harmonic generation with multi-photon excited fluorescence microscopy.
• To highlight the unique capabilities of multi-harmonic generation for imaging molecular spatial organization.

Main Methods:

• Focusing a pulsed laser beam into a sample.
• Generating harmonic up-conversion.
• Generating multi-photon excited fluorescence.
• Developing a versatile instrument combining both techniques.

Main Results:

• Both multi-harmonic generation and multi-photon excited fluorescence microscopy offer comparable resolution and signal levels.
• Harmonic generation is a coherent process highly sensitive to phase.
• Multi-harmonic generation microscopy provides unique insights into molecular spatial organization.

Conclusions:

• Multi-harmonic generation microscopy presents a novel approach for 3D imaging.
• The technique offers unique advantages over fluorescence-based methods for studying molecular organization.
• Combining harmonic generation and fluorescence in one instrument enhances versatility.