Concave Gold Bipyramid Saturable Absorber Based 1018 nm Passively Q-Switched Fiber Laser

Concave gold bipyramids (CAuBPs) exhibit enhanced saturable absorption characteristics due to their large electromagnetic-field enhancement, large third order nonlinearity and fast recovery time. In this paper, the CAuBPs are synthetized through a seed-mediated wet-chemical growth method, and a 1018 nm passively Q-switched fiber laser exploiting CAuBPs saturable absorber (SA) is demonstrated in a ring cavity. The maximum average output power of 9.61 mW is obtained under the pump power of 270 mW in Q-switched regime. The minimum pulse width is 1.83 μs at the pulse repetition rate of 97.47 kHz. The results prove that CAuBP is a promising SA with potential for important applications in the field of pulsed lasers.