Two-dimensional photonic crystal nanocavities for light localization

Summary form only given.Optical resonant cavities formed from 2D periodic high-index contrast dielectric slabs may be used to effectively guide or trap light in spatial volumes of a few cubic half-wavelengths. 2D Bragg reflection in the plane of the slab along with strong index guiding in the vertical direction provide the necessary confinement for high Q factor electromagnetic modes. Lasing action has recently been demonstrated in such a cavity in which a single hole was removed from the photonic lattice, thus providing a local energy well for photons. Due to the ability to lithographically define such cavity mode properties as emission direction, wavelength, polarization, mode volume, and quality factor these nanocavities are interesting for a variety of laser/detector applications, as well as for optical filters and switches. For the same reasons these photonic crystal based optical cavities may find use in cavity QED experiments. Apart from the obvious reduction in optical mode volume, the same functionality that makes this technology interesting for lightwave communication may also prove useful for experimental measurements of atom-photon interactions. Through the addition of input and output waveguide channels based on the same planar photonic crystal geometry one may efficiently probe and detect the cavity modes. Also, one may adjust the number of periods of photonic crystal in order to obtain vertical or in-plane emission depending on the application. We present recent room temperature laser results, as well as tuning of the cavity modes through adjustments in the local defect region, and the splitting of the cavity mode degeneracy into a pair of x and y polarized modes. Progress to date and limitations in terms of obtainable cavity Q and fabrication tolerances are also addressed.