Abstract

Theory¹-⁴ predicts that a tightly focused Gaussian light beam passing outside but near a spherical or cylindrical microcavity will preferentially excite specific cavity resonances depending on its distance to the cavity center, y. This has been called the localization prin-cjpl_ei-4 a n £ j associates light rays at a distance y = (n + 1/2) λ./2π with modes having a principal mode number, n. In effect, this is a restatement of conservation of angular momentum with ray momentum being proportional to the index of refraction, m, multiplied by the radial position of the peak of the n mode, r_n; i.e., y ≈ mr_n. In this paper, we experimental tests of the theory using two types of microcavites: spherical liquid droplets and cylindrical glass fibers. Both cavity types displayed excellent agreement with theory.

© 1998 Optical Society of America