Light-hole transitions in quantum dots: realizing full control by highly focused optical-vortex beams

Abstract

An optical-vortex is an inhomogeneous light beam having a phase singularity at its axis, where the intensity of the electric and/or magnetic field may vanish. Already well studied are the paraxial beams, which are known to carry well defined values of spin (polarization $\sigma$) and orbital angular momenta; the orbital angular momentum per photon is given by the topological charge $\ell$ times the Planck constant. Here we study the light-hole--to--conduction band transitions in a semiconductor quantum dot induced by a highly-focused beam originating from a $\ell =1$ paraxial optical vortex. We find that at normal incidence the pulse will produce two distinct types of electron--hole pairs, depending on the relative signs of $\sigma$ and $\ell$. When sign($\sigma$)$=$sign($\ell$), the pulse will create electron--hole pairs with band+spin and envelope angular momenta both equal to one. In contrast, for sign($\sigma$)$\ne$sign($\ell$), the electron-hole pairs will have neither band+spin nor envelope angular momenta. A tightly-focused optical-vortex beam thus makes possible the creation of pairs that cannot be produced with plane waves at normal incidence. With the addition of co-propagating plane waves or switching techniques to change the charge $\ell$ both the band+spin and the envelope angular momenta of the pair wave-function can be precisely controlled. We discuss possible applications in the field of spintronics that open up.

References in corpus (6)

• Optically probing the fine structure of a single Mn atom in an InAs quantum dot
• Angular momentum of focused beams: beyond the paraxial approximation
• Optically induced energy and spin transfer in non-resonantly coupled pairs of self-assembled CdTe/ZnTe quantum dots
• High fidelity all-optical control of quantum dot spins: detailed study of the adiabatic approach
• Mapping of focused Laguerre-Gauss beams: The interplay between spin and orbital angular momentum and its dependence on detector characteristics
• Single exciton spectroscopy of single-Mn doped InAs quantum dots

Cited by in corpus (5)

• Twisted-ligth--ion interaction: the role of longitudinal fields
• Formulation of the twisted-light--matter interaction at the phase singularity: beams with strong magnetic fields
• Electrons in intense laser fields with local phase, polarization, and skyrmionic textures
• Magneto-Electric Response of Quantum Structures Driven by Optical Vector Beams
• Magnetic-optical transitions induced by twisted light in quantum dots