Search

A theory of optical modes in an elliptical microcavity has been developed using Mathieu functions in elliptical coordinates. A key difference from the circular case is the splitting of doubly degenerate modes. Split optical modes have been numerically calculated and their symmetry has been determined. A method has been proposed to choose the parameters of a cavity for a certain wavelength. The difference between the energies of optical modes in the cavity with metallic walls and in the dielectric cavity is no more than ~20%. The dispersion relations of optical modes show the possibility of degeneracy of modes with different symmetries, which allows the spectral and polarization filtering of radiation of single-photon sources and the fabrication of sources of multiply entangled states.

We have studied optical properties of site-controlled GaN nanocolumns (NCs) with an insertion of InGaN QW grown on the micro-cone patterned substrate. Time-resolved photoluminescence spectroscopy reveals two bands emission. Comparison of these spectra with the emission of a separate nanocolumn, recorded by μ-CL with high spatial resolution, allows us to ascribe the higher energy band to emission from the InGaN QW situated on the top of NCs, while the lower-energy band originates from the QW in the rest area. By the modeling of the decay times and amplitudes of PL decay curves, we have exhibited a significant enhancement of signal from the QW inside the NCs. Investigation of the NCs as a Fabry-Perot cavity at eigenfrequencies around the optical transitions has revealed that the cavity modes can provide significant enhancement of the emission from the inserted QW owing to the Purcell factor.

Features of the propagation and slowing down of short light pulses (duration of ~0.1–2 ps) in one-dimensional resonant photonic crystals with various types of unit cells containing several quantum wells are discussed. It is established that the use of structures with a complex unit cell makes it possible to reduce the group velocity of exciton-polaritons along with the conservation of the width of the transparency window. The calculations show the possibility of the slowing down of a light pulse by a factor of 50 as compared to a pulse propagating in vacuum. The predicted delay time of the pulse is 2 ps at a damping of only 3–5 times.

InN optical cavities supporting low-order whispering-gallery modes up to room temperature are formed by molecular-beam epitaxy on patterned substrates. The observed switching of the mode type with increasing temperature is explained in terms of changes in the optical parameters due to a shift of the absorption edge and modification of its shape. Modeling taking into account a variation in the refractive index reproduces the typical distributions of the electromagnetic-field intensity in the cavities.