Interference of stimulated electronic Raman scattering and linear absorption in coherent control

Abstract

We consider quantum interference effects in carrier and photocurrent excitation in graphene using coherent electromagnetic field components at frequencies ω and 2ω. The response of the material at the fundamental frequency ω is presented, and it is shown that one-photon absorption at ω interferes with stimulated electronic Raman scattering (combined 2ω absorption and ω emission) to result in a net contribution to the current injection. This interference occurs with a net energy absorption ofhω and exists in addition to the previously studied interference occurring with a net energy absorption of 2hω under the same irradiation conditions. Due to the absence of a bandgap and the possibility to block photon absorption by tuning the Fermi level, graphene is the perfect material to study this contribution. We calculate the polarization dependence of this all-optical effect for intrinsic graphene and show that the combined response of the material at both ω and 2ω leads to an anisotropic photocurrent injection, whereas the magnitude of the injection current in doped graphene, when transitions at ω are Pauli blocked, is isotropic. By considering the contribution to coherent current control from stimulated electronic Raman scattering, we find that graphene offers tunable, polarization sensitive applications. Coherent control due to the interference of stimulated electronic Raman scattering and linear absorption is relevant not only for graphene but also for narrow-gap semiconductors, topological insulators, and metals.

Identification of photocurrents in topological insulators

“…Two-color photocurrents have been observed [7], and the expressions for the nonlinear optical response that describes them have been worked out in detail [8] for frequencies where states near the K points are important, with scattering included phenomenologically.Unlike most semiconductors, where two-color injection currents have been studied forhω < E g < 2hω, in undoped graphene one-photon absorption is possible at both 2ω and ω, and so complexities in the injected currents arise [9]. Yet since the lattice structure has inversion symmetry there are no one-color effects.…”

Numerical study of the optical nonlinearity of doped and gapped graphene: From weak to strong field excitation

“…However, the dependence of the nonlinearity on chemical potential, temperature, and the excitation frequency have not been systematically measured. Of the theoretical studies reported, most are still at the level of single particle approximations within different approaches, which include perturbative treatments based on Fermi's golden rule [25,26], the quasiclassical Boltzmann kinetic approach [1,2,27,28], and quantum treatments based on semiconductor Bloch equations (SBE) or equivalent strategies [3,[29][30][31][32][33][34][35][36][37][38]. When optical transitions around the Dirac points dominate, analytic expressions for the third order conductivities can be obtained perturbatively by employing the linear dispersion approximation [3,[35][36][37][38].…”

Antiferromagnetic spin valve based on a heterostructure of two-dimensional hexagonal crystals

“…Graphene has high electron mobility [18,19] and long spin relaxation lifetime [20][21][22][23]. The generation and manipulation of spin current by electronic [24,25] * Corresponding author:luom28@mail.sysu.edu.cn and optical [26][27][28][29][30][31] methods have been proposed theoretically and studied experimentally [32][33][34]. Single-layer graphenes (SLGs) and bilayer graphenes (BLGs) with the substrate proximity effect [35][36][37] or adatom doping [38] exhibit large values of spin-orbital coupling (SOC) that make the spintronic effect observable at room temperature.…”