Ultrafast switching time and third order nonlinear coefficients of microwave treated single walled carbon nanotube suspensions

TL;DR

This study investigates the ultrafast optical switching and third-order nonlinear properties of microwave treated single-walled carbon nanotube suspensions, revealing their potential for photonic applications.

Contribution

It provides new measurements of ultrafast dynamics and nonlinear coefficients for microwave treated SWCNTs, highlighting their enhanced nonlinear optical responses.

Findings

Bi-exponential ultrafast photo-bleaching with sub-picosecond time constants.

Saturation absorption and positive/negative nonlinear refraction observed.

High two-photon absorption coefficients and nonlinear indices measured.

Abstract

Microwave treated water soluble and amide functionalized single walled carbon nanotubes have been investigated using femtosecond degenerate pump-probe and nonlinear transmission experiments. The time resolved differential transmission using 75 femtosecond pulse with the central wavelength of 790 nm shows a bi-exponential ultrafast photo-bleaching with time constants of of 160 fs (130 fs) and 920 fs (300 fs) for water soluble (amide functionalized) nanotubes. Open and closed aperture z-scans show saturation absorption and positive (negative) nonlinear refraction for water soluble (amide functionalized) nanotubes. Two photon absorption coefficient,beata ~250 cm/GW (650 cm/GW) and nonlinear index, gamma ~ 15 cm^2/pW (-30 cm^2/pW) are obtained from the theoretical fit in the saturation limit to the data for two types of nanotubes.