The Electromagnetic Shielding of Optoelectronic Devices by Mesh Structures

In this work, the shielding properties of mesh structures with various cell sizes on a K108 glass substrate are studied. The transmission spectra of the samples were obtained in a frequency range from 1 GHz to 1620 THz. A comparison of the experimental transmission spectra with those obtained using several theoretical models, and a numerical calculation were carried out. The most optimal theoretical model used to describe the shielding properties of a mesh structure in the frequency range upper-bounded by a resonant frequency is the one-mode calculation model. Anti-reflection coatings were used to increase the transmission coefficient of the structures in the visible and near-IR spectral ranges. These mesh structures can be used to shield optoelectronic devices such as a video camera or a laser rangefinder from microwaves

Terahertz-to-infrared converters for imaging the human skin cancer:challenges and feasibility

Abstract Purpose: Terahertz (THz) medical imaging is a promising noninvasive technique for monitoring the skin’s conditions, early detection of the human skin cancer, and recovery from burns and wounds. It can be applied for visualization of the healing process directly through clinical dressings and restorative ointments, minimizing the frequency of dressing changes. The THz imaging technique is cost effective, as compared to the magnetic resonance method. Our aim was to develop an approach capable of providing better image resolution than the commercially available THz imaging cameras. Approach: The terahertz-to-infrared (THz-to-IR) converters can visualize the human skin cancer by converting the latter’s specific contrast patterns recognizable in THz radiation range into IR patterns, detectable by a standard IR imaging camera. At the core of suggested THz-to-IR converters are flat matrices transparent both in the THz range to be visualized and in the operating range of the IR camera, these matrices contain embedded metal nanoparticles (NPs), which, when irradiated with THz rays, convert the energy of THz photons into heat and become nanosources of IR radiation detectable by an IR camera. Results: The ways of creating the simplest converter, as well as a more complex converter with wider capabilities, are considered. The first converter is a gelatin matrix with gold 8.5-nm diameter NPs, and the second is a polystyrene matrix with 2-nm diameter NPs from copper–nickel MONEL® alloy 404. Conclusions: An approach with a THz-to-IR converter equipped with an IR camera is promising in that it could provide a better image of oncological pathology than the commercially available THz imaging cameras do