Victor Ryzhii

TL;DR: In this article, the dynamic ac conductivity of a nonequilibrium two-dimensional electron-hole system in optically pumped graphene was studied and it was shown that at sufficiently strong pumping the population inversion in graphene can lead to the negative net ac conductivities in the terahertz range of frequencies.

TL;DR: In this paper, a quantum-dot infrared phototransistor (QDIP) was proposed and considered theoretically, which utilizes intersubband electron transitions from the bound states.

TL;DR: Graphene is a one-atom-thick planar sheet of a honeycomb carbon crystal and its gapless and linear energy spectra of electrons and holes lead to nontrivial features such as giant carrier mobility and broadband flat optical response as discussed by the authors.

TL;DR: In this paper, the two-dimensional electron-hole system in a graphene-based heterostructure controlled by a highly conducting gate is studied theoretically, where the energy spectra of two-dimensions electrons and holes are assumed to be conical (neutrinolike) i.e., corresponding to their zero effective masses.

TL;DR: In this paper, fast relaxation and relatively slow recombination dynamics of photogenerated electrons and holes in an exfoliated graphene under infrared pulse excitation were reported, within a picosecond time scale, and the phase behavior of the measured terahertz electric field also showed clear Lorentzian-like normal dispersion around the gain peak.