New paper in Biomedical Optics Express!

Our new paper demonstrating a novel, widely tunable femtosecond laser for two-photon vision studies in humans is now available online.


We report the development of a widely-tunable femtosecond fiber laser system and its application for two-photon vision studies. The source is based on an Er-doped fiber laser with spectral shift up to 2150 nm, followed by a second harmonic generation module to generate a frequency-doubled beam tunable from 872 to 1075 nm. The source delivers sub-230 fs pulses with nearly-constant duration over the entire tuning range, with output powers between 0.68–1.24 mW, which corresponds to a pulse energy of 13.2–24.1 pJ. Such pulse energy is sufficient for employing a system for measurements of two-photon scotopic spectral sensitivity of two-photon vision in humans. The laser parameters allow for very efficient and safe two-photon stimulation of the human visual system, as proved by a good separation between one- and two-photon thresholds for wavelengths below 950 nm, which we have confirmed for 3 healthy subjects.

The paper is available (open access):


Dorota Stachowiak, Marcin Marzejon, Jakub Bogusławski, Zbigniew Łaszczych, Katarzyna Komar, Maciej Wojtkowski, and Grzegorz Soboń, "Femtosecond Er-doped fiber laser source tunable from 872 to 1075 nm for two-photon vision studies in humans," Biomed. Opt. Express 13, 1899-1911 (2022)


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