Diamond Raman laser and Yb fiber amplifier for in vivo multiphoton fluorescence microscopy

Area of Science:

• Biophotonics and advanced imaging techniques.
• Development of novel laser sources for microscopy.

Background:

• Two-photon excitation (TPE) microscopy requires specific wavelengths for optimal fluorophore excitation.
• High-power, cost-effective laser sources are needed for advanced TPE applications, including deep tissue imaging.

Purpose of the Study:

• To introduce novel, high-power fiber amplifiers and diamond Raman lasers for TPE.
• To provide cost-efficient and easily constructible laser sources for advanced microscopy.
• To demonstrate the utility of these sources for fast neuronal and deep tissue imaging.

Main Methods:

• Construction of a fiber amplifier and a diamond Raman laser.
• Characterization of output power and wavelengths (6.5 W at 1060 nm, 1.3 W at 1250 nm).
• Integration with a resonant scanning system for fast image acquisition.

Main Results:

• Achieved high output powers suitable for two-photon excitation of red-shifted fluorophores.
• Demonstrated compatibility with fast resonant scanning for rapid image acquisition.
• Successfully imaged neuronal activity and vasculature at depths greater than 1 mm in mouse cerebral cortex.

Conclusions:

• The developed fiber amplifier and diamond Raman laser are simple, cost-efficient, and effective for advanced TPE microscopy.
• These sources enable fast, deep-tissue imaging of biological structures, such as neuronal networks and vasculature.
• The system facilitates high-speed neuronal imaging and deep-brain imaging in vivo.