In this work, we report the realization of a polarization-insensitive grating coupler, single-mode waveguide, and ring resonator in GaN-on-Sapphire platform. We provide detailed demonstration material characterization, device simulation, experimental results. achieve coupler efficiency -5.2 dB/coupler with 1dB 3dB bandwidth 40 nm 80 nm, respectively. measure waveguide loss -6 dB/cm. The losses ...

Heterodyne measurements have been made at 533 GHz using a novel superconducting hot-electron bolometer in a waveguide mixer. The bolometer is a 0.3 mm long niobium microbridge with a superconducting transition temperature of 5 K. The short length ensures that electron diffusion dominates over electron-phonon interactions as the electron cooling mechanism, which should allow heterodyne detection...

The permeation of microwave pulses ( / = 9 . 4 G H z . pulse duration: 0 .5-0 .7 ps) through a partially ionized hydrogen plasma is investigated. At supercritical electron densities (line-averaged density: n t = 1.2-1.8 x 10 m~) a resonant enhancement of the wave amplitude is observed between the plasma column and the metallic end reflector of the waveguide. Local measurements of the electric f...

An electron beam passing through a metamaterial structure is predicted to generate reversed Cherenkov radiation, an unusual and potentially very useful property. We present an experimental test of this phenomenon using an intense electron beam passing through a metamaterial loaded waveguide. Power levels of up to 5 MW are observed in backward wave modes at a frequency of 2.40 GHz using a one mi...

We report experimental results on laser-driven electron acceleration with low divergence. The electron beam was generated by focussing 750 mJ, 42 fs laser pulses into a gas-filled capillary discharge waveguide at electron densities in the range between 1018 and 1019cm−3. Quasi-monoenergetic electron bunches with energies as high as 500 MeV have been detected, with features reaching up to 1 GeV,...

Theoretical studies [1-3] have shown that the relativistic subpicosecond electron bunches produced by high-brightness rf photoinjectors can be used to generate coherent synchrotron radiation in a free-electron maser (FEM). Furthermore, in a waveguide structure, the group velocity of the radiation can be matched to the axial bunch velocity in the helical wiggler, thus minimizing slippage in the ...

We report the direct microscopic observation of optical energy transfer from guided photonic modes in an indium tin oxide (ITO) thin film to surface plasmon polaritons (SPP) at the surfaces of a single crystalline gold platelet. The photonic and SPP modes appear as an interference pattern in the photoelectron emission yield across the surface of the specimen. We explore the momentum match betwe...

We present a new approach to fabricate three-dimensional (3D) dye-sensitized solar cells (DSSCs) by integrating planar optical waveguide and nanowires (NWs). The ZnO NWs are grown normally to the quartz slide. The 3D cell is constructed by alternatively stacking a slide and a planar electrode. The slide serves as a planar waveguide for light propagation. The 3D structure effectively increases t...