  Exerting well-defined control over the reflection $(R)$, absorption $(A)$,
and transmission $(T)$ of electromagnetic waves is a key objective in quantum
optics. To this end, one often utilizes hybrid structures comprised of elements
with different optical properties in order to achieve features such as high $R$
or high $A$ for incident light. A desirable goal would be the possibility to
tune between all three regimes of nearly perfect reflection, absorption, and
transmission within the same device, thus swapping between the cases $R\to 1$,
$A\to1$, and $T\to1$ dynamically. We here show that a dielectric interfaced
with a graphene layer on each side allows for precisely this: by tuning only
the Fermi level of graphene, all three regimes can be reached in the THz regime
and below. Moreover, we show that the inclusion of cylindrical defects in the
system offers a different type of control of the scattering of electromagnetic
waves by means of the graphene layers.
