Angle-dependent light emission from aligned multiwalled carbon nanotubes under CO2 laser irradiation

This paper reports the light emission from aligned multiwalled carbon nanotubes (MWNTs) under continuous wave CO2 laser (λ = 10.6 μm) irradiation. Results indicate that the light emission is dependent on the angle θ between the laser incident direction and the nanotube axis. The relative intensity of the light emission at certain wavelengths shows a Lorentzian feature when θ varies from 00 to 900. The Lorentzian fitting curve displays a distinct tendency between shorter (λ<600 nm) and longer wavelength (λ>700 nm). A minimum intensity was observed at θm close to 670 under shorter wavelength, whereas a maximum intensity was shown at θm of about 600 at longer wavelength. These results show the anisotropic property of aligned MWNTs