title: Wideband-tuneable, nanotube mode-locked, fibre laser.
abstract: Ultrashort-pulse lasers with spectral tuning capability have widespread applications in fields such as spectroscopy, biomedical research and telecommunications. Mode-locked fibre lasers are convenient and powerful sources of ultrashort pulses, and the inclusion of a broadband saturable absorber as a passive optical switch inside the laser cavity may offer tuneability over a range of wavelengths. Semiconductor saturable absorber mirrors are widely used in fibre lasers, but their operating range is typically limited to a few tens of nanometres, and their fabrication can be challenging in the 1.3-1.5 microm wavelength region used for optical communications. Single-walled carbon nanotubes are excellent saturable absorbers because of their subpicosecond recovery time, low saturation intensity, polarization insensitivity, and mechanical and environmental robustness. Here, we engineer a nanotube-polycarbonate film with a wide bandwidth (>300 nm) around 1.55 microm, and then use it to demonstrate a 2.4 ps Er(3+)-doped fibre laser that is tuneable from 1,518 to 1,558 nm. In principle, different diameters and chiralities of nanotubes could be combined to enable compact, mode-locked fibre lasers that are tuneable over a much broader range of wavelengths than other systems.
authors.affiliation: Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK.
authors.forename: F
authors.initials: F
authors.lastname: Wang
authors.forename: A G
authors.initials: AG
authors.lastname: Rozhin
authors.forename: V
authors.initials: V
authors.lastname: Scardaci
authors.forename: Z
authors.initials: Z
authors.lastname: Sun
authors.forename: F
authors.initials: F
authors.lastname: Hennrich
authors.forename: I H
authors.initials: IH
authors.lastname: White
authors.forename: W I
authors.initials: WI
authors.lastname: Milne
authors.forename: A C
authors.initials: AC
authors.lastname: Ferrari
mesh_terms: D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation*; D007834:Lasers; D036103:Nanotechnology / Q000295:instrumentation; D037742:Nanotubes, Carbon; D012666:Semiconductors
chemical_list: D037742:Nanotubes, Carbon