Electric currents induced by twisted light in Quantum Rings

Abstract

We theoretically investigate the generation of electric currents in quantum rings resulting from the optical excitation with twisted light. Our model describes the kinetics of electrons in a two-band model of a semiconductor-based mesoscopic quantum ring coupled to light having orbital angular momentum (twisted light). We find the analytical solution, which exhibits a "circular" photon-drag effect and an induced magnetization, suggesting that this system is the circular analog of that of a bulk semiconductor excited by plane waves. For realistic values of the electric field and material parameters, the computed electric current can be as large as microA; from an applied perspective, this opens new possibilities to the optical control of the magnetization in semiconductors.

Formulation of the twisted-light–matter interaction at the phase singularity: The twisted-light gauge

“…The research in TL spans several areas, such as the generation of beams [4,5], the interaction of TL with atoms and molecules [6,7] or with condensed matter [8][9][10][11][12][13][14][15][16][17][18][19][20]. TL has already proved to be useful in applications.…”

“…Applications in other fields are also sought, for example in quantum information technology, where the OAM adds a new degree of freedom encoding more information [24][25][26][27]. In addition, theoretical studies in solid state physics predict, for instance, that TL can induce electric currents in quantum rings [19], and new electronic transitions (forbidden for plane waves) in quantum dots [18]. This all suggests that TL can be a new powerful tool to control quantum states in nanotechnological applications.…”

Ultrashort optical-vortex pulse generation in few-cycle regime

“…The new light source well-merged with powerful control technique in time or frequency domain such as femtosecond technology enables us to carry out experiments for high-intensity field physics [4], ultrafast nonlinear spectroscopy [5][6][7], terahertz vortex generation based on radiation from coherently-accelerated charged particles along the azimuthal direction [8]. Recently, opticalvortex light sources by the use of femtosecond pulses were reported [9,10].…”

Insensitivity of spin dynamics to the orbital angular momentum transferred from twisted light to extended semiconductors

“…Bh, 78.20.Ls, 78.40.Fy, 42.50.Tx Light with orbital angular momentum (OAM), referred to as twisted light, is a relatively new field of research which has become increasingly popular [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] since Allen et al showed how twisted light beams can be easily generated from conventional laser beams [18]. Recently, the theoretical foundation of the optical excitation of solids and nanostructures with twisted light has been established [19][20][21][22][23][24][25][26][27], and experimental studies with twisted light on semiconductors have been carried out [28,29].One motivation for such studies is the prospect of using the large amounts of angular momentum that twisted light can carry in order to control the spin dynamics of electrons, thus adding a flexible tool to the active field of spin control [30][31][32][33][34][35][36][37][38][39]. In this context two different mechanisms need to be distinguished.…”

“…Recently, the theoretical foundation of the optical excitation of solids and nanostructures with twisted light has been established [19][20][21][22][23][24][25][26][27], and experimental studies with twisted light on semiconductors have been carried out [28,29].…”