Comparative performances of 60nm and 80nm gold nanoparticles based mode-locker for erbium doped fiber laser

The study evaluates the influence of a nanocomposite-based gold nanoparticle (Au-NPs) saturable absorber (SA) with particle sizes of 60 and 80 nm on the generation of ultrashort pulses in an erbium-doped fiber laser. The saturable absorber was created by coating a nanocomposite of Au-NPs and polydimethylsiloxane (PDMS) onto the surface of a microfiber using a spin coater. The Au-NP-based SA was subsequently incorporated into a ring cavity of an erbium-doped fiber laser, and its performance was evaluated by comparing the SA properties and pulse quality for both 60nm and 80nm Au-NP-based SAs. The study discovered that Au-NPs larger than 60nm led to inadequate optical performance for mode-locking applications. This decrease was noticeable in the shift of the center wavelength of the optical spectrum from about 1559nm to 1532nm and an increase in pulse duration from 940fs using 60nm Au-NPs SA to 1229fs using 80nm Au-NPs SA. The findings suggest that the ideal size for Au-NPs, ensuring an efficient mode-locker, should not exceed 60nm. This previously unpublished study is crucial in determining the optimal gold nanoparticle size for producing ultrashort pulse output that fulfills the specific needs of a given system.