  Dielectric resonators are open systems particularly interesting due to their
wide range of applications in optics and photonics. In a recent paper [PRE,
vol. 78, 056202 (2008)] the trace formula for both the smooth and the
oscillating parts of the resonance density was proposed and checked for the
circular cavity. The present paper deals with numerous shapes which would be
integrable (square, rectangle, and ellipse), pseudo-integrable (pentagon) and
chaotic (stadium), if the cavities were closed (billiard case). A good
agreement is found between the theoretical predictions, the numerical
simulations, and experiments based on organic micro-lasers.
