Perturbation theory for resonances in wave-chaotic resonant cavities

We develop a perturbation theory for the lifetime and emission intensity for narrow resonances in asymmetric resonant cavities. In the semiclassical approximation both the inverse lifetime Γ and the emission intensity I(θ) are expressed as sums over the contributions of rays which escape the resonator by refraction. The theory describes the highly directional emission from “bow-tie” modes found in recent experiments on deformed semiconductor microlasers.