Evaluation of compact pulsed lasers for two-photon microscopy using a simple method for measuring two-photon excitation efficiency
Year: 2023
Type: article
Abstract: SignificanceTwo-photon (2p) microscopy has historically relied on titanium sapphire pulsed lasers that are expensive and have a large footprint. Recently, several manufacturers have developed less expensive compact pulsed lasers optimized for 2p excitation of green fluorophores. However, quantitative evaluation of their quality is lacking.AimWe describe a simple approach to systematically evaluate 2p excitation efficiency, an empiric measure of the quality of a pulsed laser and its ability to elicit 2p induced fluorescence.ApproachBy measuring pulse width, repetition rate, and fluorescence output, we calculated a measure of 2p excitation efficiency η, which we compared for four commercially available compact pulsed lasers in the 920 to 930 nm wavelength range.Results2p excitation efficiency varied substantially among tested lasers. The Coherent Axon exhibited the best 2p excitation efficiency (1.09 ± 0.03), exceeding that of a titanium sapphire reference laser (defined to have efficiency = 1). However, its measured fluorescence was modest due to its long pulse width. Of the compact lasers, the Toptica Femtofiber Ultra exhibited the best combination of measured fluorescence (0.75 ± 0.01) and 2p excitation efficiency (0.86 ± 0.01).ConclusionsWe describe a simple method that both laser developers and end users can use to benchmark the 2p excitation efficiency of lasers used for 2p microscopy.
Source: Neurophotonics
Authors: Samir Saidi, Matthew Shtrahman
Institution: University of California San Diego
Language: English
Subfield: Biophysics
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $1,675
Award: G587603475
OpenAlex ID: W4388653168