  We examine several ways to manipulate the loss in electromagnetic cloaks,
based on transformation electromagnetics. It is found that, by utilizing
inherent electric and magnetic losses of metamaterials, perfect wave absorption
can be achieved based on several popular designs of electromagnetic cloaks. A
practical implementation of the absorber, consisting of ten discrete layers of
metamaterials, is proposed. The new devices demonstrate super-absorptivity over
a moderate wideband range, suitable for both microwave and optical
applications. It is corroborated that the device is functional with a
subwavelength thickness and, hence, advantageous compared to the conventional
absorbers.
