Light amplification by internal reflection from an inverted medium

Amplification of Electromagnetic Field in Total Internal Reflection from a Region of Inverted Population

Reflection of light from an inhomogeneous inverted medium with limited amplifying region

Light amplification in reflection from an inhomogeneous inverse medium with dispersion

The theory of the amplification effect upon total internal reflection of wave beams by inverted media

Photon reflection at the boundary of an inverted medium

Amplification by reflection from an active medium