Gold nanobipyramids as a saturable absorber for passively Q-switched Yb-doped fiber laser operation at 1.06 μm

In this letter, gold nanobipyramids (Au-NBPs) are prepared using a seed-mediated growth method. The longitudinal surface plasmon resonance (SPR) absorption peak of the Au-NBPs is located at 1068 nm by controlling the aspect of the materials. To verify the absorption properties of the Au-NBP saturable absorber (SA), a passively Q-switched Yb-doped fiber laser is demonstrated. The maximum average output power of 3.33 mW is obtained under a pumped power of 340 mW. The minimum pulse width is 2.6 mu s at a pulse repetition rate of 66.3 kHz. The results prove that Au-NBP are a promising SA with the potential for important applications in the field of pulse lasers.