950 nm Femtosecond Laser by Directly Frequency-Doubling of a Thulium-Doped Fiber Laser

We demonstrate a compact and efficient femtosecond laser operating at ~950 nm by directly frequency-doubling of a mode-locked Tm-doped fiber laser. The laser is based on a highly compact architecture, with a dispersion-managed oscillator together with only one-step frequency conversion. The output pulse width is ~270 fs, with a repetition rate of 22.1 MHz and a pulse energy of 12.9 nJ. It is believed that the greatly simplified setup makes the current laser well suited for two-photon microscopy and other biomedical and clinical applications.