Evaluation of compact pulsed lasers for two-photon microscopy using a simple method for measuring two-photon...

Area of Science:

• Biophotonics
• Microscopy
• Laser Technology

Background:

• Two-photon (2p) microscopy traditionally uses expensive, large titanium sapphire lasers.
• Emerging compact pulsed lasers offer a more affordable option for 2p excitation of green fluorophores.
• Quantitative data on the performance of these new compact lasers is limited.

Purpose of the Study:

• To develop and apply a systematic method for evaluating the 2p excitation efficiency of compact pulsed lasers.
• To compare the performance of four commercially available compact pulsed lasers for 2p microscopy applications.

Main Methods:

• Developed a method to calculate 2p excitation efficiency based on pulse width, repetition rate, and fluorescence output.
• Measured and compared the 2p excitation efficiency of four compact pulsed lasers (920-930 nm).
• Utilized a titanium sapphire laser as a reference for efficiency comparison.

Main Results:

• Significant variations in 2p excitation efficiency were observed among the tested compact lasers.
• The Coherent Axon showed the highest 2p excitation efficiency, surpassing the titanium sapphire reference.
• The Toptica Femtofiber Ultra provided the optimal balance of fluorescence output and 2p excitation efficiency among compact lasers.

Conclusions:

• A straightforward method for benchmarking 2p excitation efficiency is presented for laser developers and users.
• The Toptica Femtofiber Ultra emerges as a strong candidate for 2p microscopy due to its balanced performance.
• This evaluation aids in selecting optimal compact lasers for advanced imaging techniques.