Quantum \v{C}erenkov Effect from Hot Carriers in Graphene: An Efficient Plasmonic Source

TL;DR

This paper demonstrates a novel, efficient 2D Cerenkov emission mechanism in graphene, enabling ultrafast electrical-to-plasmonic energy conversion by leveraging graphene plasmons' low phase velocity.

Contribution

It introduces a new concept of Cerenkov emission from hot carriers in graphene, overcoming relativistic particle limitations for nanoscale devices.

Findings

Efficient plasmonic Cerenkov emission observed in graphene.

Tunable and ultrafast electrical-to-plasmonic energy conversion.

Potential applications in nanoscale photonic devices.

Abstract

Graphene plasmons (GPs) have been found to be an exciting plasmonic platform, thanks to their high field confinement and low phase velocity, motivating contemporary research to revisit established concepts in light-matter interaction. In a conceptual breakthrough that is now more than 80 years old, \v{C}erenkov showed how charged particles emit shockwaves of light when moving faster than the phase velocity of light in a medium. To modern eyes, the \v{C}erenkov effect (\v{C}E) offers a direct and ultrafast energy conversion scheme from charge particles to photons. The requirement for relativistic particles, however, makes \v{C}E-emission inaccessible to most nanoscale electronic and photonic devices. We show that GPs provide the means to overcome this limitation through their low phase velocity and high field confinement. The interaction between the charge carriers flowing inside graphene and GPs presents a highly efficient 2D \v{C}erenkov emission, giving a versatile, tunable, and ultrafast conversion mechanism from electrical signal to plasmonic excitation.