Abstract Splitting circularly polarized waves is desirable for high‐data‐rate wireless communications and study of molecular chirality at terahertz frequencies. Typically, this functionality achieved using bulk optical systems with limitations in material availability, bandwidth, efficiency. As an alternative, metasurfaces spatially varying broadband birefringence are employed to attain the same functionality. It demonstrated that a metasurface designed gradually rotated birefringent...

Polarization control is shown to enhance functionalities of terahertz waves in various applications. As a step toward introducing efficient practical devices operating the band, we propose and experimentally validate free-standing three-layer polarization converter transmission. The device can efficiently convert linearly polarized wave its orthogonal counterpart. Our comprises split-ring H-shaped resonators inserted between two layers wire gratings. sole dielectric material cyclic olefin...

Polarization control of electromagnetic waves has wide applications in the field communications, imaging, and remote sensing. Recent designs periodic two-dimensional devices or metasurfaces employed for polarization are limited efficiency, bandwidth, allowable incidence angle. This is attributed to high dissipation dielectric material used less-optimal device configuration. We propose experimentally validate a reflective linear converter metasurface with acceptance angle terahertz regime....

Effective-medium-clad dielectric waveguides are purely built into a single high-resistivity float-zone silicon wafer with their claddings defined by deep subwavelength perforations. The substrate-free while supporting both E <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sup> <sub xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> and xmlns:xlink="http://www.w3.org/1999/xlink">y</sup> modes low loss dispersion. This article extends the...

This article presents a narrow-band terahertz absorber using miniaturized unit cells. The is made of three metallic layers separated from each other low-loss cyclic olefin copolymer as dielectric spacers. A high quality factor (Q) obtained first-order resonating structure with additional capacitive loading formed by the top two layers. circuit model developed for analysis and design proposed absorber. designed shows 1% fractional bandwidth more than 90% absorption around center frequency 0.5...

Polarization conversion of terahertz waves is important for applications in imaging and communications. Conventional wave plates used polarization are inherently bulky operate at discrete wavelengths. As a substitute, we employ reflective metasurfaces composed subwavelength resonators to obtain similar functionality but with enhanced performance. More specifically, demonstrate low-order dielectric place commonly planar metallic achieve high radiation efficiencies. demonstration the concept,...

Polarization conversion devices are key components in spectroscopy and wireless communications systems. Conventional terahertz waveplates made of natural birefringent materials typically suffer from low efficiency, narrow bandwidth, substantial thickness. To overcome the limitations associated with conventional waveplates, a quarter-wave metasurface enhanced efficiency wide bandwidth is proposed. The transmissive rigorously designed based on an extended semi-analytical approach employing...

We propose a series of integrated Bragg grating filters with performance enhancement via the concept effective medium. The bandstop are built in high-resistivity silicon wafer and operated over WR-3.4 band (220–330 GHz) in-plane polarization. proposed designs use an additional degree freedom controlling refractive index so as to fully potential structures. As result, high insertion loss typically observed at low-frequency bound due weak wave confinement can be reduced, while radiation caused...

Abstract Reflectarrays offer unique potential for beamforming at terahertz frequencies as they combine the advantages of low‐profile phased arrays and high‐efficiency parabolic antennas. However, one challenge associated with reflectarrays is their bandwidth limitation resulting from nonlinear phase response. To enhance bandwidth, a single‐layer stub‐loaded resonator proposed constructing reflectarrays. This design shows smooth near‐linear response complete 360° coverage around frequency....

Polarization conversion is useful for studies of chiral structures in biology and chemistry, polarization diversity communications. It conventionally realized with wave plates, which, however, present challenges due to limited material availability, as well narrow bandwidth low efficiency at terahertz frequencies. To enhance efficiency, the concept Huygens' metasurface adopted here a transmissive half-wave plate. The designed following optimal frequency-independent circuit parameters...

Frost is estimated to cost Australian grain growers <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi mathvariant="normal">$</mml:mi> </mml:math> 360 million in direct and indirect losses every year. Assessing frost damage manually barley labor intensive involves destructive sampling. To mitigate against significant economic loss, it crucial that assessment decisions on whether cut for hay or continue harvest are made soon after has occurred. In this paper,...

Abstract Many image processing operations involve the modification of spatial frequency content images. Here we demonstrate object-plane filtering utilizing angular sensitivity a commercial spectral bandstop filter. This approach to all-optical is shown generate real-time pseudo-3D images transparent biological and other samples, such as human cervical cancer cells. work demonstrates potential non-local, non-interferometric approaches for uses in label-free cell imaging dynamical monitoring.

Thin film transistors (TFTs) offer unparalleled opportunities for the fabrication of multifunctional electronic and optoelectronic devices. In this work, we report a vacuum-free liquid metal exfoliation technique rapidly printing ∼2 nm-thick layer oxide from molten tin. We explore effect rapid thermal annealing at 450 °C on stoichiometry, morphology, crystal structure resulting tin nanosheets. The annealed samples exhibit dominant SnO2 phase high degree transparency (>99%) in visible...

As an alternative to metallic resonators, dielectric resonators can increase radiation efficiencies of metasurfaces at terahertz frequencies. Such subwavelength made from low-loss materials operate on the basis oscillating displacement currents. For full control electromagnetic waves, it is essential that around their resonant modes. Thus, understanding nature these resonances crucial towards design implementation. To this end, array silicon a quartz substrate designed in transmission The...

A terahertz metasurface consisting of metallic coaxial disk-ring resonators is demonstrated by Wendy S. L. Lee et al. in article number 1700852. This capable deflecting normally incident left and right handed circularly polarized waves into opposite directions. Furthermore, this beam splitting capability preserved over a broadband range highly efficient. Potential applications include polarization multiplexing communications analyzing the response chiral molecules.

We integrate infrared-to-visible upconverting nanoparticles with an asymmetric dielectric metasurface to enhance their upconversion efficiency. An enhancement of up ~100 times is achieved. also demonstrate imaging using fabricated devices.

Polarimetry of electromagnetic waves is important for molecular spectroscopy and high-data rate wireless communications in the terahertz frequency regime. Conventional bulk optical systems used to achieve this functionality have several drawbacks including scarcity available materials, narrow bandwidth low efficiency. To overcome these limitations, we employ metasurfaces with spatially changing broadband birefringence attain same functionality. We present a metasurface designed birefringent...

This publisher’s note contains corrections to Opt. Lett. 46 , 4164 ( 2021 ) OPLEDP 0146-9592 10.1364/OL.431285 .

One major hurdle for antennas created from metallic resonators is their low radiation efficiencies due to increasing Ohmic loss at terahertz frequencies. A potential solution overcome this substitute metal with dielectric materials in designing resonators. Dielectric resonator (DRAs) resonate based on the confinement of displacement current, specific resonance Hence, mitigated DRAs. An array silicon quartz realized examine magnetic 0.625 THz. This work employs a near-field imaging technique...

Upconversion lasers capable of lasing at low pump intensities would enable interesting applications including passive night vision goggles. Fernandez-Bravo et al. demonstrated such a laser based on upconverting nanoparticles (UCNPs) and plasmonic nanostructure in which the lattice plasmon mode was coupled to emission from UCNPs [1]. In this work, we present an asymmetric dielectric metasurface with resonances both absorption wavelengths further enhance performance these lasers. This titanium...

Metasurfaces provide the platform for a myriad of applications owing to exotic properties that are not commonly found in nature. Typically, metasurfaces constructed using arrays metallic or dielectric subwavelength resonators. In this paper, we compare two designs broadband terahertz half-wave mirrors, namely and resonator metasurface. Although both have different operational mechanisms, fractional bandwidth achieved by meta-surfaces is more than 67% with reflection efficiencies greater 80%.

A single-layer stub-loaded terahertz resonator is presented for constructing reflectarrays with enhanced bandwidth in article number 1900791 by Xiaolong You and co-workers. focusing reflectarray that transforms the incident collimated beam into a focused realized using this as building element, exhibiting improved intended. The constructed can be applied various beamforming functions applications communications, sensing imaging.

Linear-to-linear polarization conversion of electromagnetic wave has application in various fields including communications, imaging and sensing. Available polarization-control devices enabled by metasurfaces are limited bandwidth, efficiency acceptance angle. Herein, a reflective half-wave mirror composed T-shaped resonators is proposed experimentally evaluated. Measured results show bandwidth 95% 100% around center frequency 0.7 THz for the normal 45° angle incidence. The measured agree...