Asymptotic exchange coupling of quasi-1D excitons in carbon nanotubes

TL;DR

This paper derives an analytical expression for biexciton binding energy in carbon nanotubes, enabling analysis of non-linear optical properties and potential applications in tunable optoelectronic devices.

Contribution

It provides a new analytical model linking biexciton energy to exciton properties and external conditions in carbon nanotubes.

Findings

Biexciton binding energy depends on inter-exciton distance and exciton binding energy.

Calculated non-linear absorption lineshapes show asymmetric Rabi splitting.

Results are relevant for tunable optoelectronic applications.

Abstract

An analytical expression is obtained for the biexciton binding energy as a function of the inter-exciton distance and binding energy of constituent quasi-one-dimensional excitons in carbon nanotubes. This allows one to trace biexciton energy variation and relevant non-linear absorption under external conditions whereby the exciton binding energy varies. The non-linear absorption lineshapes calculated exhibit characteristic asymmetric (Rabi) splitting as the exciton energy is tuned to the nearest interband plasmon resonance. These results are useful for tunable optoelectronic device applications of optically excited semiconducting carbon nanotubes, including the strong excitation regime with optical non-linearities.