Generation of sub-20-fs pulses from a graphene mode-locked laser

Abstract

We demonstrate, what is to our knowledge, the shortest pulses directly generated to date from a solid-state laser, mode locked with a graphene saturable absorber (GSA). In the experiments, a low-threshold diode-pumped Cr³⁺:LiSAF laser was used near 850 nm. At a pump power of 275 mW provided by two pump diodes, the Cr³⁺:LiSAF laser produced nearly transform-limited, 19-fs pulses with an average output power of 8.5 mW. The repetition rate was around 107 MHz, corresponding to a pulse energy and peak power of 79 pJ and 4.2 kW, respectively. Once mode locking was initiated with the GSA, stable, uninterrupted femtosecond pulse generation could be obtained. In addition, the femtosecond output of the laser could be tuned from 836 nm to 897 nm with pulse durations in the range of 80-190 fs. We further performed detailed mode locking initiation tests across the full cavity stability range of the laser to verify that pulse generation was indeed started by the GSA and not by Kerr lens mode locking.

Nonlinear Optics with 2D Layered Materials

“…Broad operation bandwidth of graphene was also demonstrated by the wide wavelength‐tunable output (Figure c) . Thus far, 2DLM‐based ultrafast lasers have been reported to produce mode‐locked pulses with the output wavelength covering from 635 nm to 2.8 µm, pulse duration of sub‐20 fs (Figure d), the repetition rate of >10 GHz, and the average power of >10 W . Overall, the advantages of 2DLM‐based saturable absorbers include broad operation bandwidth, fast recovery time, electrical tunability, cost‐effective, easy fabrication and integration, and multifunctionality (e.g., integrated photodetector and modulator).…”

The Property, Preparation and Application of Topological Insulators: A Review

“…Some examples of excellent parameters were listed in Table 6 . It can be seen from the table that the pulse duration of graphene-based laser reached 19 fs [ 229 ]. However, the S/N was not as high as TI-based lasers.…”

All-optical modulation with 2D layered materials: status and prospects

“…Moreover, graphene-based saturable absorbers show much higher saturation fluence compared with SESAMs, especially near the bandgap of the SESAM materials [154]. Thus, graphene-based saturable absorbers only have advantages for lasers with temporarily ultrashort pulses (pulse duration near or even less than 100 fs) and widely tunable wavelengths [156], and more efforts are required to improve the general performance. For other 2D semiconductor-based saturable absorbers such as TMDs and black phosphorus, they show strong wavelength-dependent saturation fluence similar with SESAMs, but they also share the advantages of graphene as being flexible and disadvantages as being volatile to thermal damage [157][158][159].…”