We review quantum mechanical and optical pseudo-Hermitian systems with an emphasis on PT-symmetric systems important for optics and electrodynamics. One of the most interesting and much discussed consequences of PT symmetry is a phase transition under which the system eigenvalues lose their PT symmetry. We show that although this phase transition is difficult to realize experimentally, a similar transition can be observed in quasi-PT-symmetric systems. Other effects predicted for PT-symmetric systems are not specific for these systems and can be observed in ordinary fully passive systems.

Optical bistability of a spaser and criteria of its appearance are studied theoretically. The effective transmission coefficient of a spaser is calculated. This allows for considering a "mirrorless" spaser bistability in the same way as that of a nonlinear Fabry-Perot cavity. It is shown that at sufficiently high losses in a spaser, due to the bistability, kink waves may propagate along a one-dimensional chain of spasers. This wave propagates even if the pumping is below the threshold of spasing. At low losses in spaser, quasiperiodic dissipative structures emerge in the spaser chain. The dynamics of the origin of such structures has a self-assembling character.

We demonstrate the existence of a spectrally narrow localized surface state, the so-called optical Tamm state, at the interface between one-dimensional magnetophotonic and nonmagnetic photonic crystals. The state is spectrally located inside the photonic band gaps of each of the photonic crystals comprising this magnetophotonic structure. This state is associated with a sharp transmission peak through the sample and is responsible for the substantial enhancement of the Faraday rotation for the corresponding wavelength. The experimental results are in excellent agreement with the theoretical predictions.

We study the optical properties of a photonic crystal interfaced with a uniform medium with the negative dielectric constant or with another photonic crystal. We show that, at such an interface, nonpropagating surface states may arise. These states result in a sharp feature in the transmission and reflection spectra of the system. We also show that interfacing magnetic and nonmagnetic photonic crystals gives rise to giant Faraday and Kerr effects.