Carbon nanodots derived from organo-templated zeolites for femtosecond mode-locked fiber laser

Carbon nanodots (CNDs) have been widely investigated due to their physicochemical and optical properties. However, the nonlinear saturable absorption property and its application in laser technology is rarely reported. Here, we report the CNDs as an ideal saturable absorber (SA) for ultra-stable femtosecond mode-locked fiber laser at a wavelength of 1.5 mu m. The mono-sized CNDs of 2 nm are fabricated from a dipropylamine-templated zeolite precursor calcination with a temperature of 380 C. The nonlinear saturable absorption property of the assynthesized CNDs is investigated by using a balanced twin-detector measurement system. The modulation depth and saturable intensity are measured to be 33 % and 3.1 MW/cm2, respectively. By inputting the CNDs SA into the erbium-doped fiber laser (EDFL) ring cavity, a highly stable mode-locked EDFL with pulse width of 388 fs and single-to-noise ratio (SNR) of 84.4 dB can be obtained. In addition, stable soliton pairs with single-pulse width of 422 fs and SNR of 84.1 dB can also be achieved. These findings demonstrate that the carbon dots can be used as an ideal SA and has promising applications in ultrafast photonics.