Passively Q-switched Fiber Lasers Based on Concave Gold Bipyramids Saturable Absorbers

摘要

In our experiment, a kind of novel gold nanoparticles - concave gold bipyramids (CAuBPs) withlarge electromagnetic-field enhancement and broader plasmonic tuning rangehave been used as a saturable absorber (SA). Passively Q-switched thulium-doped and ytterbium-doped fiber lasers have been demonstrated based on CAuBPs SAs, the longitudinal surface plasmon resonance (LSPR) bands of which are located at 1 μm and 2 μm. In the 1 μm region, the maximum average output power of 9.61 mW is obtained with the shortest pulse width of 1.83 μs at the pulse repetition rate of 97.47 kHz. In the 2μm waveband, 9.72 mW average output power is obtained with the minimum pulse width of 4.56μs at the repetition rate of 19.9 kHz. To the best of our knowledge, it's the first time that CAuBP has been used as SA, which verifies the saturable absorption properties of CAuBPs in the infrared range experimentally.