**Acknowledgements**

The performance of the Tm-doped fiber laser mode-locked with the described BP-based saturable absorber is depicted in **Figure 15**. The laser generated soliton-shaped optical spectra centered at 1910 nm with 5.8 nm of FWHM bandwidth (a), which corresponded to a 739 fs pulse (b). It is worth mentioning that the authors claimed a high damage threshold of the BP layers. The laser was pumped with relatively high power (up to 400 mW) and the SA was not

**Figure 15.** Optical spectrum generated by the BP mode-locked Tm-doped laser (a) and the autocorrelation trace of the

Black phosphorus in form of nanopalettes (NPs) was also used in combination with microfibers for evanescent field interaction. In their work, Yu et al. [129] reported that the SA had a modulation depth of 9.8% measured at 1.93 μm. A stable mode-locking operation at 1898 nm was achieved with a pulse width of 1.58 ps and a fundamental repetition rate of 19.2 MHz.

Similarly to graphene, BP is also suitable for operation in the midinfrared. In 2016, Wang et al. [130] demonstrated the first Cr:ZnSe laser incorporating BP as saturable absorber. However, the laser was not mode-locked but Q-switched. Generation of 189 ns pulses with average

In summary, the recent most important advances in the field of ultrashort-pulsed lasers utilizing two-dimensional materials have been presented. A group of 2D materials, such as graphene, topological insulators, and transition metal dichalcogenides, have unambiguously revolutionized the field of mode-locked fiber-based and solid-state lasers. The discovery of unique optical properties of graphene has initiated an extremely fast progress in the science of two-dimensional nanomaterials, which strongly contributed to the development of novel ultrafast laser sources. It is evident that the interest in 2D material-based photonics will not

output power of 36 mW was obtained at 2.4 μm wavelength.

damaged or degraded during any of the performed experiments [37].

142 Two-dimensional Materials - Synthesis, Characterization and Potential Applications

emitted 739 fs pulse (b).

**5. Summary and outlook**

slow down in the next years.

The author acknowledges the help and support from the members of the Laser & Fiber Electronics Group, especially Jaroslaw Sotor, Jakub Boguslawski, Maciej Kowalczyk, Jan Tarka, Karol Krzempek, and Krzysztof M. Abramski. The author also like to kindly thank the collaborators from the Institute of Electronic Materials Technology (Warsaw, Poland) for their excellent work on graphene fabrication and characterization. The research presented in this chapter was supported by the National Science Centre (NCN, Poland) under grants no. DEC-2013/11/D/ST7/03138 and DEC-2014/13/B/ST7/01699, and by the statutory funds of the Chair of EM Field Theory, Electronic Circuits and Optoelectronics (grant no. S50044).
