Spin-dependent electron transport of a waveguide with Rashba spin--orbit coupling in an electromagnetic field

We investigate theoretically the spin-dependent electrontransport in a straight waveguide with Rashba spin--orbit coupling(SOC) under the irradiation of a transversely polarizedelectromagnetic (EM) field. Spin-dependent electron conductance andspin polarization are calculated as functions of the emittingenergy of electrons or the strength of the EM field by adopting the modematching approach. It is shown that the spin polarization can bemanipulated by external parameters when the strength of RashbaSOC is strong. Furthermore, a sharp step structure is found to existin the total electron conductance. These results can be understoodby the nontrivial Rashba subbands intermixing and the electronintersubband transition when a finite-range transversely polarizedEM field irradiates a straight waveguide.