Ultrafast absorptive and refractive nonlinearities in multiwalled carbon nanotube films

Abstract

By using femtosecond laser pulses at a wavelength range from 720 to 780 nm, we have observed absorptive and refractive nonlinearities in a film of multi-walled carbon nanotubes grown mainly along the direction perpendicular to the surface of quartz substrate. The Z-scans show that both absorptive and refractive nonlinearities are of negative and cubic nature in the laser irradiance range from a few to 300 GW/cm 2 . The magnitude of the third-order nonlinear susceptibility, χ, is of an order of 10 -11 esu. The degenerate pump-probe measurement reveals a relaxation time of ~ 2 ps. *

Nonlinear optical absorption and reflection of single wall carbon nanotube thin films by Z-scan technique

“…The β value of our SWNT thin film is about two orders of magnitude greater than those of CaF 2 and BaF 2 crystals, 19 which have been widely used as optical windows and achromatic lenses. Our value of β is also large compared with those obtained for multi-walled carbon nanotube (MWNT) films, 6 silicon nanocrystals, 12 and…”

“…is deeply grateful for the CONACYT-México grants: 56787 (Laboratory for Nanoscience and Nanotechnology Research-LINAN) and 58899 (Inter-American Collaboration). We are also indebted to Dr. F. Kobayashi for his technical assistance in the experiments and to the Gene Research Center, Shinshu University, for providing us 6 its facilities. 7 …”

“…Very recently, intensive studies on the nonlinear optical properties of SWNTs have been carried out theoretically 1 and experimentally. [2][3][4] It is believed that SWNTs can be used in the fabrication of optical limiting and switching devices due to their nonlinear optical properties upon absorption [4][5][6] and its fast decay time of less than 1 picoseconds. 2,[7][8][9] These nonlinear properties are related to the third-order nonlinear susceptibility χ (3) , which is considered to be a complex quantity: 10 ( ) ( ) ( 3…”

Multiwalled Carbon Nanotubes Beaded with ZnO Nanoparticles for Ultrafast Nonlinear Optical Switching

“…[54] On the other hand, the transmittance from ZnO/ MWNTs (coated for 1 min) is only slightly smaller than that from as-grown MWNTs. However, for the sample coated for 5 min, the normalized transmittance is significantly reduced.…”

Directing carbon nanotubes from aqueous phase to o/w interface for heavy metal uptaking

“…The pH values of aqueous liquid were measured by a pH meter (Model 320-S, Mettler Toledo Co.). The CNTs concentration (mg/ L) was determined by a UV-vis spectrometer (Shimadzu UV-240) at the absorbance of 256 nm, which was attributed to the π-π* transition of CNTs (Elim et al 2004;Xu et al 2006). Zeta potential of the dispersed CNTs was measured using a Zetasizer Nano analyzer (Malvern DLS), and all measurements were conducted using 100 mg/L CNTs suspension.…”