Optimal tuning of lasing modes through collective particle resonance

One of the current challenges in laser optics is to take advantage of the resonant modes within particles to obtain high-quality microcavities with low threshold. We present a study of the effect that the internal resonances of individual particles have on the emitted intensity, and demonstrate how optimal tuning of the size and separation of the particles can enhance the quality factor by more than four orders of magnitude. The potential applications of this work on the design of an optimal microcavity and on a random laser are discussed. © 2004 Optical Society of America OCIS codes: 290.4210, 160.2540, 160.0160.