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Metamaterials with desired resonance frequency and high field enhancement are highly demanded in many applications including high harmonic generation, molecular sensing, and non-linear optics. For such purposes, especially sub-wavelength gaps, various parameters of the nano-resonators including gap width, length, period have been optimized, while the effect of height on the performance of the resonators...
We proposed a novel planar meta-atom structure supporting higher order Fano resonances. The unit cell consists of a plasmonic defective corrugated metallic disk (CMD). The numerical and experimental results reveal that higher order Fano resonances can be generated at terahertz frequencies when symmetric CMD is broken with small defective angle. Such higher order Fano resonances result from the coupling...
We present two terahertz detectors composed of microbolometer sensors (vanadium oxide and silicon pn diode) and metamaterial absorbers monolithically integrated into a complementary metal oxide semiconductor (CMOS) process. The metamaterial absorbers were created using the metal-dielectric-metal layers of a commercial CMOS technology resulting in low-cost terahertz detectors. The scalability of this...
We demonstrate THz metamaterials as efficient label-free detectors for microorganisms such as fungi, bacteria, and viruses. A shift in the resonant frequency is observed following the deposition of various living and viable microorganisms, which arises due to the change in the effective dielectric constant in a capacitive gap of the metamaterials. The metamaterial sensing is a universal method, while...
We have experimentally investigated electronical excitation of Fano resonances in subwavelength slits. These resonances can provide strong concentration of electromagnetic waves under subwavelength conditions in microwave and terahertz regime as analogous to plasmonic Fano resonances in optics regime. It is observed that the quality factors of the resonances become exceedingly high by introducing...
We have measured the transmission spectra of splitring resonator metamaterials from 0 to 10 THz for parallel and perpendicular polarizations. Calculations of the lattice and plasmon mode dispersion relations in combination with electromagnetic simulations confirm the presence of multiple higher order lattice and plasmon modes. High frequency high-Q resonances that result from plasmon-lattice mode...
We experimentally demonstrate linear frequency conversion on time-variant terahertz (THz) metasurface. The proposed metasurface is originally designed to have two resonances, and with optical pumping, the resonances are merged into one. When a THz pulse passes through the metasurface during this merging process, a frequency component corresponding to the merged mode is generated.
We describe experimental measurements and simulations of a switchable THz metasurface device in a slab waveguide geometry. The device exhibits giant phase modulation of the TE1 mode at particular frequencies determined by the metamaterial geometry. Simulations predict that a 2π phase shift can be realized in an interaction length of only a few millimeters.
This paper describes a method to improve the return loss, gain, and directivity of a planar antenna. Our approach is based on using electromagnetic band gap (EBG) structures within a dielectric substrate. We designed two type of antennas: a reference one — a standard patch antenna- and a patch antenna having an EBG substrate, both of them work at an operation frequency of 15 GHz. The reference antenna...
A W-band backward wave oscillator (BWO) based on metamaterial (MTM) slow wave structure (SWS) is presented as a novel high power microwave generator. Particle-in-cell (PIC) simulation is performed to evaluate the efficiency of the W-band MTM-based BWO (MTMBWO), and the MTMBWO can reach saturated output power of 2.78MW with an electronic efficiency of 31.68% at frequency of 84.87GHz.
In this paper, we demonstrate that efficient phase modulation of THz wave can be addressed by active and enhanced resonant GaN high electron mobility transistor (HEMT) array metamaterials. We exploit the large phase shift of THz wave by using an enhanced resonant metamaterial structure which couples the traditional dipolar and inductance-capacitance resonances. By electrical controlling of the carrier...
Metallic split ring resonators have achieved broad interest in the field of metamaterials and light matter interaction in general. We present split ring resonators fabricated from the van-der Waals material Boron Nitride and designed to operate in the reststrahlen band arround 1400 cm−1. We observe two distinct modes in far field transmission spectra exhibiting high quality factors of 55 and 88. Simulations...
We suggest a novel method for a portable and real-time THz imager operating at room temperature based on metamaterial-cholesteric liquid crystal hybrid structure. The induced local field enhancement at metasurface improved the sensitivity of the THz imager.
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