We report on the far-field emission characteristics of two-dimensional photonic crystal-based organic waveguide lasers. The photonic crystals possess square vein, triangular, and honeycomb symmetries. The two-dimensional gratings are fabricated by employing soft lithographic methods. The far-field pattern that we observe is a result of out-of-plane diffractive coupling of the laser emission generated in the plane of the waveguide. This emission pattern offers a convenient and powerful way to evaluate the nature of laser action in such resonators. In devices which possess defects/breaks in the periodicity of the two-dimensional grating, laser emission generated in-plane is scattered in the plane of the waveguide. This phenomenon is the photonic crystal analogue of Kikuchi scattering in electronic crystals.

Enhancing light-matter interactions on a chip is of paramount importance for classical and quantum photonics, sensing and energy harvesting applications. Several photonic geometries have been developed, allowing high extraction efficiencies, enhanced light-matter interactions and control over the spontaneous emission dynamics of solid-state quantum light sources. To this end, a device geometry resilient to nanofabrication imperfections, providing high-quality light confinement and control over the emitted light properties, would be desirable. We demonstrate that aperiodic arrangements, whose geometry is inspired by natural systems where scattering elements are arranged following Fibonacci series, represent a platform for enhancing the light-matter interaction in on-chip nano-photonic devices, allowing to achieve efficient visible light confinement. We use optically-active defect centers in silicon nitride as internal light sources to image and characterize, by means of micro-photoluminescence spectroscopy, the individual optical modes confined by photonic membranes with Vogel-spiral geometry. By studying the statistics of the measured optical resonances, in partnership with rigorous multiple scattering theory, we observe log-normal distributions and report quality factors with values as high as 2201±443. Our findings improve the understanding of the fundamental physical properties of light-emitting Vogel-spiral systems and show their application to active nano-photonic devices. These results set the basis for further development of quantum devices that leverage the unique properties of aperiodic Vogel spiral order on a chip, including angular momentum states, thus producing mode structures for information processing and communications on the chip.