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The paper presents a theoretical study of the eigenmodes of a misaligned ring multi-mirror laser cavity one or several arms of which are filled with an inhomogeneous medium. We start with posing the general problem of calculation of the radiation characteristics for a ring resonator with arbitrary inhomogeneities of the medium and mirrors, in the paraxial approximation. Then the general relations are specified for the lens-like resonator model in which the real and imaginary parts of the refractive index, as well as the phase and amplitude corrections performed by the mirrors, quadratically depend on the transverse coordinates. Explicit expressions are obtained for the eigen frequency and spatial characteristics of the radiation via the coefficients of the Hermite-Gaussian functions describing the complex amplitude distributions at the mirrors. The main results are formulated in terms of linear relations between positions of the resonator mode axis at the mirrors and the misalignment parameters (small shifts and tilts of the mirrors). The explicit results display the coefficients of the above linear relations. They are calculated for the 3-mirror cavity with using a specially developed approach employing peculiar conditions to the coefficients form that follow from very general considerations of two groups: 1) Independence of the resulting frequency shifts on the sequence in which the misalignments are made (this is the base of the energy method for the resonator analysis, which is essentially generalized and improved); 2) Geometrical symmetry of the resonator. The results of calculations can be used in order to control the radiation characteristics in relation to the resonator misalignments, in particular, for analysis of the output radiation stability and sensitivity to small changes of the cavity configuration.
Unidirectional photonic edge states arise at the interface between two topologically-distinct photonic crystals. Here, we demonstrate a micron-scale GaAs photonic ring resonator, created using a spin Hall-type topological photonic crystal waveguide.
The frequency stability of lasers is limited by thermal noise in state-of-the-art frequency references. Further improvement requires operation at cryogenic temperature. In this context, we investigate a fiber-based ring resonator. Our system exhibits
A topologically protected ring-resonator formed in valley photonic crystals is proposed and fabricated on a silicon slab. The unidirectional transmission and robustness against structure defects of its resonant modes are illustrated. Coupled with top
Microcombs -- optical frequency combs generated in coherently-driven nonlinear microresonators -- have attracted significant attention over the last decade. The ability to generate two such combs in a single resonator device has in particular enabled
Photon sources are fundamental components for any quantum photonic technology. The ability to generate high count-rate and low-noise correlated photon pairs via spontaneous parametric down-conversion using bulk crystals has been the cornerstone of mo