  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($\sigma$)$\neq$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.
