The linear and nonlinear optical properties of trigonal zigzag graphene nanoflakes

Abstract

Using the Hartree–Fock Su–Sheriffer–Heeger model and the sum-over-state method the linear and nonlinear polarizabilities, the dc Stark effect and the degenerate two-photon absorption (TPA) cross sections of the small-size trigonal zigzag graphene nanoflakes (TZGNs) have been investigated. The obtained dispersion spectra of the second- and third-order polarizabilities and the degenerate TPA cross sections of size-2 and size-3 TZGNs, which, respectively, have 22 carbon atoms with two edge states and 33 carbon atoms with three edge states, show peak values of the order of 10−28 esu, 10−32 esu and 103 GM, respectively. Furthermore, even-size TZGNs show electrostatic induced transparency due to their sizable dc Stark effect, which makes them suitable for linear and nonlinear optoelectronic devices.