Nonlinear optical response from excitons in soliton lattice systems

TL;DR

This paper investigates the nonlinear optical response, specifically third-harmonic generation (THG), in soliton lattice systems of conjugated polymers, revealing significant enhancement of nonlinear effects with doping and soliton number.

Contribution

It demonstrates a substantial increase in THG in doped soliton lattice systems and highlights the impact of soliton number and boundary conditions on nonlinear optical responses.

Findings

THG increases by about 100 times at 10% doping

THG is significantly larger with two solitons in open systems

Enhancement is consistent across different Coulomb interaction strengths

Abstract

Exciton effects on conjugated polymers and the resulting optical nonlinearities are investigated in soliton lattice systems. The magnitude of the THG at the 10 percent doping increases by the factor about 10^2 from that of the neutral system. The huge increase by the order two is common for several choices of Coulomb interaction strengths, and is seen in open systems as well as in periodic systems. We also find that the THG enhances much larger when the number of solitons is two in the open boundaries. This new fact should be attractive to the experimentalists. Keywords: Semi-empirical models and model calculations, Electron density and excitation spectra calculations, Many-body and quasiparticle theories, Low-bandgap conjugated polymers