Direct generation of 3.5 optical-cycle pulses from rare-earth laser

• DOI: 10.1364/opticaopen.28455185
• Publication Date: 2025-02-24T04:47:20Z
• Authors: Yongguang Zhao; Ning Zhang; Yinyin Wang; Heng Ding; Fei Liang; Jun Xu; Haohai Yu; Huaijin Zhang; Valentin Petrov

Unlike the conventional mode-locked laser where cooling system is normally used for the gain medium, here, we propose a new strategy to originally extend the modelocked bandwidth through increasing the crystal temperature. Mode-locking of thulium-laser with superbroadband (> 600 nm) centered at 2.05-μm has been realized, corresponding to a pulse duration of 26 fs (3.5 optical cycles), which represents the shortest pulses ever achieved from the Tm/Ho-lasers in the 2-μm spectral range and the fewest cycles from all the present-day RElasers. This work, as a proof of principle study, opens a new route for mode-locked laser towards direct generation of extremely short pulses.<p></p>