Lawsone dye material as potential saturable absorber for Q-switched erbium doped fiber laser

In this paper, lawsone (2-hydroxy-1,4-naphthoquinone), a natural dye material is proposed and demonstrated as a saturable absorber (SA) for passive Q-switching operation in Erbium-doped fiber laser (EDFL) cavity. The lawsone-based SA was fabricated using a liquid-phase exfoliation technique. A tiny piece of the lawsone film was then cut and slot-in between two fiber ferrules so that it can easily be incorporated into a laser cavity as a Q-switcher. A stable Q-switched pulse train operation was observed with the repetition rate of 80 kHz and pulse width as narrow as 1.7 µs at 1564 nm wavelength. The maximum pulse energy and average power were obtained to be 53 nJ and 4.3 mW, respectively. The results indicate that the lawsone material can be a suitable SA for Q-switched pulse laser operating at the 1.5-µm region. To the best of our knowledge, this is the first time lawsone material is utilized as a SA device for generating Q-switched pulse.