Nonlinear refractive index and absorption coefficient of single-shell semiconductor carbon nanotube

Abstract

The nonlinear refractive index and absorption coefficient of single-shell semiconductor carbon nanotubes (CNs) are calculated based on the two-band approximation and Genkin-Mednis approach. The results of nonlinear refractive index and absorption coefficient reach the order of 10−8 and 10−4 cm2·W−1 separately, which indicates that CNs have wonderful nonlinear optical properties. Taking into account the temperature effect and overlapping of σ and π orbits, the effect of relaxation term and chiral angle is discussed. The results show that the smaller the relaxation term, the larger the nonlinear absorption coefficient and refractive index. At the same time, CNS with different chiral angles have different results due to their different energy gap.