Terahertz-wave detector on silicon carbide platform

We developed a novel terahertz-wave detector fabricated on a SiC platform implementing an InP/InGaAs Fermi-level managed barrier (FMB) diode. The FMB diode epi-layers were transferred on a SiC substrate, and a waveguide coupler and filters were monolithically integrated with an FMB diode. Then, fabricated detector chip was assembled in a fundamental mixer module with a WR-3 rectangular-waveguide input port. It exhibited a minimum noise equivalent power as low as 3e-19 W/Hz at around 300 GHz for a local oscillator power of only 30 microwatts.

A FABRY-PEROT METARESONATOR SUPPORTING TRAPPED-MODE RESONANCES

Purpose: Investigation of the electrodynamic properties of a Fabry-Perot metaresonator formed by two parallel perfectly conducting, two-dimensionally periodic, two-element screens of finite thickness with rectangular holes. The resonator is excited by a plane linearly polarized electromagnetic wave. The basic cell of each of the screens used as the metaresonator mirrors contains two lengths of rectangular waveguides of different transverse sections. Design/methodology/approach: An operator method for solving the 3D problems of electromagnetic wave diffraction by multielement two-dimensionally periodic structures is used in the study. The computation algorithm uses the partial domain technique and the method of generalized scattering matrices. Findings: As follows from the results of the numerical modeling made, the magnitude of the plane wave reflected from the metaresonator turns to zero at fixed frequencies lying below the cutoff frequencies for the rectangular waveguide sections embedded in the resonator mirrors. The effect of the total electromagnetic wave transmission through the metaresonator at the first lower frequency is characterized by a strong localization of the electromagnetic field in the resonator volume. The reason is excitation of the metaresonator by the exponentially descending field penetrating inside the resonator through the evanescent holes at the resonance frequency. The second low-frequency resonance of the total electromagnetic wave transmission through the metaresonator is associated with the trapped-mode resonance, which is observed in multielement two-dimensionally periodic structures. This case is characterized by a strong localization of the electromagnetic field from both sides near the metaresonator mirror surfaces. Conclusions: The unique electrodynamic properties of the metaresonator can find application in the devices for measuring the electrophysical parameters of composite materials with high losses. The effect of strong localization of the electromagnetic field both in the resonator volume and near the mirror surfaces can be used for monitoring the gaseous substances in crowded places. Key words: two-dimensionally periodic screen; rectangular waveguide; Fabry-Perot metaresonator; reflection factor; evanescent waveguide; trapped-mode resonance

Metasurface-based Augmented Reality Headset Equipped with an Eye Movement Monitoring System

In this paper, a metasurface-based waveguide display equipped with an eye movement monitoring system is presented. In the suggested device, the functions of the eye movement system and AR are completely independent of each other and are designed in two separate sections at wavelengths 775 nm and 635 nm respectively. In the next part, in order to investigate the effects of the shape of the waveguide on FOV and efficiency, a multifunctional display system comprise of a single rectangular waveguide with two sensitive polarization channels are designed to operate as an AR and eye movement monitoring system simultaneously at visible and IR wavelengths respectively. In both devices, monitoring eye movements can be done over the range of -24º to 24º and the digital images are displaced in the user’s FOV based on horizontal eye positions. Although the first suggested system is heavier than one, its FOV is almost more than twice of the second system. The results indicate that metasurface-based waveguide technology can be considered as an appropriate platform for developing wearable eye movement systems.