Carbon nanomaterials as nonlinear optical modulators for pulsed laser generation at near-infrared region

Abstract

In this study, carbon nanoparticles (CNPs) were experimentally investigated as novel saturable absorbers (SAs) capable of delivering strong ultrashort pulses in a passively Q-switched fiber laser. Carbon nanoparticles produced by candle burning and laser ablation can act as saturable absorbers (SAs). In addition, the nonlinear saturable absorption properties of the two synthetic CNPs in telecommunication region (1.5 μm) are investigated. Nonlinear optical measurements show that both SAs have good saturable absorption properties with average modulation depths of about ∼1 and 5 % at 1560 nm. These candle soot carbon nanoparticles (CSC-np) and laser ablation carbon nanoparticles (LAC-np) based SAs, can be used as a building blocker for the generating of stable Q-switched pulses in the near-infrared region. The shortest pulse duration measured with CSC-np and LAC-np are 5.62 and 3.87 μm, respectively. The pulse energy, peak power and SNR were also compared with both SA types at the highest pump power. The damage threshold and long-term stability of the CSC-cn SA and LAC-np were also explored. To the best of the author's knowledge, it is the first comparison of performance and long-term stability of EDFL based on two experimental techniques CSC-np and LAC-np based SAs. These results indicate that LAC-np SA provide have several advantages, including a high damage threshold, good saturable absorption, and optimum stability over a long time compared to CSC-np SA.