Exciton lasing in carbon nanotubes below the population inversion threshold via phonon-mediated stimulated emission

Fuente: arXiv
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Main Authors: Forno, Stefano Dal, Battiato, Marco
Format: Preprint
Published: 2023
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author Forno, Stefano Dal
Battiato, Marco
author_facet Forno, Stefano Dal
Battiato, Marco
contents Excitonic optical transitions in carbon nanotubes (CNTs) have been extensively studied for at least two decades. However, exploiting these transitions to produce a lasing effect has been proved unpractical due to the difficulties of achieving an excitonic population inversion in carbon nanotubes. In this work we show that lasing is theoretically possible at a much lower exciton population threshold by taking advantage of phonon stimulated emission. Specifically, the so-called Anti-Stokes transitions, where light is generated by the creation of a phonon and the annihilation of an exciton, can be used to sustain the coherent emission of photons. These transitions have been overlooked for long due to their low intensity as a consequence of the low occupancy of the associated phonon branches. We show that the best conditions to achieve the lasing effect are met in CNTs with i) excitons of non-zero momentum, ii) a strong exciton-phonon coupling and iii) narrow exciton transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2311_05962
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Exciton lasing in carbon nanotubes below the population inversion threshold via phonon-mediated stimulated emission
Forno, Stefano Dal
Battiato, Marco
Mesoscale and Nanoscale Physics
Materials Science
Excitonic optical transitions in carbon nanotubes (CNTs) have been extensively studied for at least two decades. However, exploiting these transitions to produce a lasing effect has been proved unpractical due to the difficulties of achieving an excitonic population inversion in carbon nanotubes. In this work we show that lasing is theoretically possible at a much lower exciton population threshold by taking advantage of phonon stimulated emission. Specifically, the so-called Anti-Stokes transitions, where light is generated by the creation of a phonon and the annihilation of an exciton, can be used to sustain the coherent emission of photons. These transitions have been overlooked for long due to their low intensity as a consequence of the low occupancy of the associated phonon branches. We show that the best conditions to achieve the lasing effect are met in CNTs with i) excitons of non-zero momentum, ii) a strong exciton-phonon coupling and iii) narrow exciton transitions.
title Exciton lasing in carbon nanotubes below the population inversion threshold via phonon-mediated stimulated emission
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2311.05962