# Polarized photoluminescence clocks ultrafast pseudospin relaxation in graphene

## TL;DR

This study uses polarization-resolved photoluminescence spectroscopy to measure ultrafast pseudospin relaxation in graphene, revealing a lifetime of approximately 12 femtoseconds, which advances understanding of pseudospin dynamics in 2D materials.

## Contribution

The paper introduces a novel experimental method to measure ultrafast pseudospin relaxation in graphene, providing quantitative insights into pseudospin lifetime.

## Key findings

- Pseudospin relaxation time in graphene is approximately 12 fs.
- Polarization-resolved photoluminescence effectively probes pseudospin dynamics.
- The approach enhances tools for graphene pseudospintronics research.

## Abstract

Electronic states in 2D materials can exhibit pseudospin degrees of freedom, which allow for unique carrier-field interaction scenarios. Here, we investigate ultrafast sublattice pseudospin relaxation in graphene by means of polarization-resolved photoluminescence spectroscopy. Comparison with microscopic Boltzmann simulations allows to determine a lifetime of the optically aligned pseudospin distribution of $12\pm 2\,\text{fs}$. This experimental approach extends the toolbox of graphene pseudospintronics, providing novel means to investigate pseudospin dynamics in active devices or under external fields.