Transient charge and energy balance in graphene induced by ultrafast photoexcitation

Transient charge and energy balance in graphene induced by ultrafast photoexcitation.

Ultrafast optical pump-probe spectroscopy measurements on monolayer graphene reveal significant optical nonlinearities. We show that strongly photoexcited graphene monolayers with 35 fs pulses quasi-instantaneously build up a broadband, inverted Dirac-fermion population. Optical gain emerges and directly manifests itself via a negative conductivity at the near-infrared region for the first 200 ...

Thermodynamic picture of ultrafast charge transport in graphene

The outstanding charge transport properties of graphene enable numerous electronic applications of this remarkable material, many of which are expected to operate at ultrahigh speeds. In the regime of ultrafast, sub-picosecond electric fields, however, the very high conduction properties of graphene are not necessarily preserved, with the physical picture explaining this behaviour remaining unc...

Ultrafast photo-induced charge transfer unveiled by two-dimensional electronic

Competing ultrafast energy relaxation pathways in photoexcited graphene.

For most optoelectronic applications of graphene, a thorough understanding of the processes that govern energy relaxation of photoexcited carriers is essential. The ultrafast energy relaxation in graphene occurs through two competing pathways: carrier-carrier scattering, creating an elevated carrier temperature, and optical phonon emission. At present, it is not clear what determines the domina...

Energy Balance of Uniformly Accelerated Charge*t

If the electromagnetic field of a uniformly accelerated charge is computed by means of Liknard-Wiechert potentials, it is found that the result does not correspond to a single source. Besides the original uniformly accelerated charge there is also a second charge, which is spread on a plane recessing in the opposite direction with the velocity of light. The work performed by this second charge ...