Abstract
We theoretically investigate charged collective modes in a two-dimensional conductor with hot electrons where the instantaneous mode frequencies gradually increase or decrease with time. We show that the loss compensation or even amplification of the modes may occur. We apply our theory to two types of collective modes in graphene, the plasmons and the energy waves, which can be probed in optical pump-probe experiments.
- Received 26 January 2016
DOI:https://doi.org/10.1103/PhysRevLett.117.076805
© 2016 American Physical Society