Gold nanorods (GNRs) with two different aspect ratios were successfully utilized as saturable absorbers (SAs) in passively Q-switched Nd:LLF laser emitting at 1.34 μm. Based on the GNRs with an aspect ratio of 5, a maximum output power of 1.432 W was achieved, and the narrowest pulse width was 328 ns with a repetition rate of 200 kHz. But in the case of the GNRs with the aspect ratio of 8, a maximum output power of 1.247 W was achieved, and the narrowest pulse width was 271 ns with a repetition rate of 218 kHz. Our experimental results reveal that the aspect ratios of GNRs have different saturable absorption effects at a specific wavelength. In other words, for passively Q-switched lasers at a given wavelength, we are able to select the most suitable GNRs as an SA by changing their aspect ratio.
Qian Qizhang, Wang Nan, Zhao Shengzhi, Li Guiqiu, Li Tao, Li Dechun, Yang Kejian, Zang Jie, Ma Houyi. Gold nanorods as saturable absorbers for the passively Q-switched Nd:LLF laser at 1.34 μm[J]. Chinese Optics Letters, 2019, 17(4): .