Passive mode locking of ceramic Nd: YAG using (7, 5) semiconducting single walled carbon nanotubes

Passive mode-locking of a ceramic Nd: YAG laser was demonstrated using highly purified single walled carbon nanotubes (SWCNTs) as the saturable absorber (SA). Poly [(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,10-an-thracene)] or PFO was used to extract a purified sample of semiconducting SWCNTs that consisted of mainly (7, 5) nanotubes (∼80% of the SWCNT ensemble). The pulses had a near Fourier transform-limited pulse width of about 8.3 ps in a non-dispersion compensated setup. In addition, Z-scan investigations revealed that SWCNT SA had a saturation intensity of about 1.7 MW cm−2 with a modulation depth of about 6% and a non-saturable loss of about 5.5%.

Research highlights
► Mode-locking of ceramic Nd: YAG using (7,5) semiconducting nanotubes as saturable absorbers.
► Saturable absorbers contains mainly (7, 5) carbon nanotubes (∼ 80% of ensemble) and has lower optical losses and lower saturation intensity at around (1040 ± 30 nm).
► This enhances the ease of mode-locking and results in higher output powers.