Actively Q-switched thulium-doped silica fiber laser at 0.82 μm

We demonstrate a Q-switched, cladding-pumped thulium-doped silica fiber laser operating at 0.82 μm, delivering energies up to 18 μJ in 530-ns pulses at a repetition rate of approximately 675 Hz. The system employs in-band pumping of an in-house-fabricated double-clad thulium-doped fiber (TDF). Q-switching was achieved by a mechanical optical chopper inside the laser cavity. To the best of our knowledge, this is the first reported demonstration of a Q-switched, cladding-pumped silica-based TDF laser at this wavelength, offering the potential for a power-scalable, compact, robust, and cost-effective source for high pulse energies in this wavelength range.