Passively Q-switched pulses from ytterbium-doped fiber laser (YDFL) using copper oxide (CuO) nanoparticles as a saturable absorber

A high pulse energy Q-switched ytterbium-doped fiber laser (YDFL) based on copper oxide (CuO) nanoparticles as a saturable absorber (SA) is demonstrated. The CuO nanoparticles have been fabricated into a thin film using a liquid-phase exfoliation method then it was integrated into a laser cavity to act as Q-switcher. The proposed Q-switched YDFL operates at a central wavelength of 1035.4 nm with a 3-dB bandwidth of 0.26 nm. The Q-switched laser has a repetition rate range from 57 kHz to 104 kHz by varying the pump power from 179 mW to 226.5 mW, while the pulse width was tuned from 4.5 µs to 2.2 µs. Relatively, high pulse energy around 0.192 µJ was achieved at an average output power of 20 mW. This laser with high pulse energy can be seen as a very promising pulsed laser source in many industrial and optical sensing applications. To the best of our knowledge, this is the first demonstration of a Q-switched fiber laser using CuO-SA in YDF.