Nanotubes in chitin mode locker for passive mode-locked fibre laser in 2.0 µm region

• Main Authors: Mohamad Rashid, Nur Nadhirah, Ahmad, Harith, Ismail, Mohammad Faizal, Lokman, Muhammad Quisar, Zuikafly, Siti Nur Fatin, Yahaya, Hafizal, Nordin, Nur Azmah, Wan Nawawi, Wan Mohd. Fazli, Ahmad, Fauzan
• Format: Article
• Language: English
• Published: MDPI 2023
• Subjects: Q Science (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utm.my/106210/1/FauzanAhmad2023_NanotubesinChitinModeLockerforPassive.pdf; http://eprints.utm.my/106210/; http://dx.doi.org/10.3390/photonics10030257

This research demonstrated an ultrafast passively mode-locked thulium-holmium doped fibre laser (THDFL) using a carbon nanotube (CNT)-chitin composite film as a saturable absorber (SA). The CNTs were fabricated using ultrasonic-assisted liquid-phase exfoliation, and the chitin biopolymer was derived from oyster mushrooms (Pleurotus Ostreatus). The free-standing SA successfully performed a mode-locking operation at a threshold input pump power of 203 mW with an operating wavelength of 1908.53 nm. The generated mode-locked pulses had repetition rate, pulse width, and signal-to-noise ratio (SNR) values of 16 MHz, 1.1 ps, and 69 dB, respectively. The work demonstrates the potential of CNTs embedded in chitin biopolymer as a sustainable and environmentally friendly SA for a wide range of applications, particularly for pulsed lasers.