Abstract

The degree of optical confinement attained by a planar microcavity can be expressed in terms of the mode radius which is proportional to $\lambda \sqrt{\text{Q}}$, where λ is the wavelength and Q is the quality factor of the mode.¹ Under the presence of gain the radius is expected to increase as the effective Q-value increases. Similarly, the emission linewidth for a broadband medium in a microcavity is confined to ω/Q which will decrease as the effective Q-value increases. Here ω is the resonant angular frequency of the mode.² In a previous paper we have reported on these aspects of a planar microcavity laser using a dye solution.³ Good agreements between theory and experiment were obtained for the spontaneous emission or to the emission below threshold with respect to both the mode radius and the spectrum. However, only poor agreements were obtained above threshold: the mode radius was smaller and the linewidth was larger than expected.

© 1995 IEEE