Investigation of passively Q-switched and mode-locked operation using Cu nanoparticles doped Indium Selenide as saturable absorber at 1.5-μm region

A reliable Q-switched and mode-locked operation at the 1.5-mu m region has been demonstrated using copper nanoparticles (Cu NPs)-doped Indium Selenide (In2Se3). The Cu NPs were produced using pulsed laser ablation (PLA) in a PVA solution before mixed it with In2Se3 solution. Then, the Cu/In2Se3 solution was dry casted into a petri dish and peeled off from the petri dish after it was completely dry to form a free-standing (without sub-strate) Cu/In2Se3 film as a saturable absorber since this technique offers simplicity and is easy to integrate into the laser cavity. Q-switched pulses were generated at the operating wavelength of 1561.9 nm with a threshold pump power of 24.13 mW. A short pulse width of 2.54 mu s, with a repetition rate of 122.60 kHz, attained a maximum pump power of 125.63 mW. The highest pulse energy obtained is 145.84 nJ, with an output power maximum of 17.88 mW on average. A soliton was generated as 100 m SMF integrated into the EDF laser cavity with the center of a wavelength of 1562.2 nm, a pulse width of 3.59 ps, and a peak power of 1.68 kW. These results prove that Cu/In2Se3 shows excellent potential as a SA material that operates in the 1.5-mu m region.