Mesoporous Carbon Nanospheres as Broadband Saturable Absorbers for Pulsed Laser Generation

Broadband pulsed laser generation is demonstrated by using mesoporous carbon nanospheres (MCNs) as saturable absorbers (SAs). The MCNs are prepared by a silica-assisted method, and then mixed with sodium carboxymethylcellulose (NaCMC) to form the MCNs film. The film not only shows strong absorption from visible to mid-infrared spectral region, but also possesses the nonlinear saturable absorption properties. As the MCNs film is inserted into the laser cavity, a mode-locked laser at 1 mu m and Q-switched lasers at 1.56 and 2 mu m are realized, respectively. In addition, by depositing the MCNs onto tapered fiber as an SA, a mode-locked fiber laser at 2 mu m is also demonstrated. The results show that MCNs are promising SA material for broadband pulsed laser generation.