  Incorporating both gain and loss into electromagnetic systems provides
possibilities to engineer effects in unprecedented ways. Concerning
electromagnetic effects in isotropic media that have concurrently electric and
magnetic responses, there is in fact a degree of freedom to distribute the gain
and loss in different effective material parameters. In this paper, we
analytically scrutinize wave interactions with those media, and, most
importantly, we contemplate the extreme scenario where such media are
anti-Hermitian. Considering various conditions for excitation, polarization,
and geometry, we uncover important effects and functionalities such as lasing
into both surface waves and propagating waves, conversion of evanescent source
fields to transmitted propagating waves, full absorption, and enhancing
backward to forward scattering ratio. We hope that these findings explicitly
show the potential of anti-Hermiticity to be used in optical physics as well as
microwave engineering for creating and using unconventional wave phenomena.
