Sapphire-based graphene saturable absorber for long-time working femtosecond lasers

Nanosized indium selenide saturable absorber for multiple solitons operation in Er3+-doped fiber laser

With the advances in the field of ultrafast photonics occurring so fast, the demand for optical modulation devices with high performance and soliton lasers which can realize the evolution of multiple soliton pulses is gradually increasing. Nevertheless, saturable absorbers (SAs) with appropriate parameters and pulsed fiber lasers which can output abundant mode-locking states still need to be further explored. Due to the special band gap energy values of few-layer indium selenide (InSe) nanosheets, we have prepared a SA based on InSe on a microfiber by optical deposition. In addition, we demonstrate that our prepared SA possesses a modulation depth and saturable absorption intensity about 6.87% and 15.83 MW/cm², respectively. Then, multiple soliton states are obtained by dispersion management techniques, including regular solitons, and second-order harmonic mode-locking solitons. Meanwhile, we have obtained multi-pulse bound state solitons. We also provide theoretical basis for the existence of these solitons. The results of the experiment show that the InSe has the potential to be an excellent optical modulator because of its excellent saturable absorption properties. This work also is important for improving the understanding and knowledge of InSe and the output performance of fiber lasers.

CVD-Bi2Te3 as a saturable absorber for various solitons in a mode-locked Er-doped fiber laser

In this work, we report about high energy and various solitons' operation by using high-efficiency topological insulator bismuth telluride (Bi₂Te₃) nanofilms as broadband saturable absorbers in the passively mode-locked Er-doped fiber laser. The Bi₂Te₃ film was successfully synthesized by chemical vapor deposition (CVD). Excellent characteristics of the dark-bright pulse pairs, bright pulses, and multiharmonics have been investigated experimentally by adjusting the polarization state. At the same time, the maximum average output power was 40.18 mW, and the single-pulse energy was 20.91 nJ. As we all know, it is the various solitons of the first generation with large pulse energy in an Er-doped fiber laser with Bi₂Te₃ as saturable absorber. The experimental results show that CVD Bi₂Te₃ can be used as an excellent candidate in mode-locked fiber lasers.

Dual-wavelength passively Q-switched Nd:GYSGG laser by tungsten disulfide saturable absorber

A dual-wavelength passively Q-switched Nd:GYSGG laser using vacuum evaporating tungsten disulfide (WS₂) as a saturable absorber was demonstrated for the first time to the best of our knowledge. The WS₂ saturable absorber was prepared simply by evaporating nanometer WS₂ powders onto a quartz substrate in a vacuum. By inserting the WS₂ saturable absorber into the laser cavity, stable Q-switched laser operation was achieved with a maximum average output power of 367 mW, a pulse repetition rate of 70.7 kHz, the shortest pulse width of 591 ns, and pulse energy of about 1.05 μJ. By vacuum evaporation method, a high-quality WS₂ saturable absorber can be produced, and it seems to be a suitable method for fabrication of 2D transition metal dichalcogenides.

Diode-pumped passively dual-wavelength Q-switched Nd:GYSGG laser using graphene oxide as the saturable absorber

The performance of a diode end-pumped passively Q-switched dual-wavelength Nd:GYSGG laser operating at 1057.28 and 1060.65 nm with graphene oxide as the saturable absorber was demonstrated. The maximum dual-wavelength average output power of 521 mW was achieved under the absorbed pump power of 5.4 W, corresponding to the optical-to-optical conversion and slope efficiency of 9.8% and 21%, respectively. The minimum pulse width was 115 ns with a pulse repetition rate of 338 kHz.