Optical gain was found in strongly confined CdSe quantum dots. As a re
sult of a multitude of one- and two-electron-hole pair transitions, th
e gain region is broad and quasi-continuous and stretches below the ab
sorption edge. We present a model for gain in a quasi-zero-dimensional
quantum confined semiconductor system that agrees well with the femto
second experiments. (C) 1996 Optical Society of America