  I theoretically study the behavior of strong pulses exciting emitters inside
a cavity. The ensemble is supposed to be inhomogeneously broadened and the
cavity matched finding application in quantum storage of optical or RF photons.
My analysis is based on energy and pulse area conservation rules predicting
important distortions for specific areas. It is well supported by numerical
simulations. I propose a qualitative interpretation in terms of slow-light. The
analogy with the free space situation is remarkable.
