In comparison with conventional lasers, topological lasers are more robust and can be immune to disorder or de-fects if lasing occurs in topologically protected states. Previously reported were almost exclu-sively based on the first-order photonic insulators. Here, we show that achieved zero-dimensional corner state a second-order insulator, which is Kagome wave-guide array rhombic configuratio...

Abstract This paper reports the fabrication and first demonstration of all-dielectric crystalline grating–waveguide reflectors comprising a Sc 2 O 3 waveguide grown on sub-wavelength-patterned sapphire substrate. Rigorous coupled-wave analysis is employed to simulate operation structure, suggesting 100% resonance reflectivity in theory. Structuring substrate achieved using inductively coupled p...

This paper demonstrates a digital waveguide implementation of a six-hole woodwind tonehole lattice, based on theory and measurements published by Keefe (1981). Woodwind tonehole transmission-matrix parameters are converted to traveling-wave scattering parameters suitable for digital waveguide implementation. Second-order digital filters are designed to approximate the reflection and transmissio...

We analyze the resonant linear and nonlinear transmission through a photonic crystal waveguide side-coupled to a Kerr-nonlinear photonic crystal resonator. First, we extend the standard coupled-mode theory analysis to photonic crystal structures and obtain explicit analytical expressions for the bistability thresholds and transmission coefficients which provide the basis for a detailed understa...

A metallic slot waveguide, with a dielectric strip embedded within, is investigated for the purpose of enhancing the optics-to-THz conversion efficiency using the difference-frequency generation (DFG) process. To describe the frequency conversion process in such lossy waveguides, a fully-vectorial coupled-mode theory is developed. Using the coupled-mode theory, we outline the basic theoretical ...

This thesis reports on the design and experimental verification of two novel high efficiency quasi-optical mode converters for gyrotron oscillators. Gyrotrons produce high order TEm,p modes (m, p > > 1) at high frequencies (100-300 GHz). These modes must be converted to low order linearly polarized modes for transmission in corrugated waveguides or open mirror transmission lines. Because tradit...