相关论文: High-frequency Limits for 3D-Printed Gradient-inde…

We present an automated design procedure for the rapid realization of wideband millimeter-wave lens antennas. The design method is based upon the creation of a library of matched unit-cells which comprise wideband impedance matching…

Gradient index (GRIN) fibers are used to improve the design of many fiber optic devices. However, the properties of the GRIN fiber must be determined to optimally engineer a device which incorporates GRIN fiber components. The index of…

Modern communication systems will require antennas with adaptive functionality which are able to modify their performance based on the requirements of the channel. For example, mobile ad-hoc networks need directive antennas that are able to…

We present the design, simulation, and planned fabrication process of a flat high resistivity silicon gradient index (GRIN) lens for millimeter and submillimeter wavelengths with very low absorption losses. The gradient index is created by…

We present the design, fabrication, and characterization of a 100 mm diameter, flat, gradient-index (GRIN) lens fabricated with high-resistivity silicon, combined with a three-layer anti-reflection (AR) structure optimized for 160-355 GHz.…

Biconical-type antennas featuring high directivity have been designed, created, and tested in anechoic chamber. Results in the range between 1 and 5 GHz are presented in this article. In particular, two different configurations have been…

Many works in elasticity have exploited the concept of gradient index (GRIN) lenses, borrowed from optics, for wave focusing and control. These effects are particularly attractive for cloaking, absorption or energy harvesting applications.…

Gravitational lensing is generally treated in the geometric optics limit; however, when the wavelength of the radiation approaches or exceeds the Schwarzschild radius of the lens, diffraction becomes important. Although the magnification…

We propose a general method for designing wideband matching tapers in inhomogeneous media where phase velocity is coupled to the taper impedance profile. Such tapers are used to match wideband gradient index (GRIN) lens antennas. To…

Very high resolution (R>150,000) spectra of a small sample of nearby K-dwarfs have been acquired to measure the line asymmetries and central wavelength shifts caused by convective motions present in stellar photospheres. This phenomenon of…

Stacked layers of metal meshes embedded in a dielectric substrate are routinely used for providing spectral selection at THz frequencies. Recent work has shown that particular geometries allow the refractive index to be tuned to produce…

Transformation optics methods and gradient index electromagnetic structures rely upon spatially varied arbitrary permittivity. This, along with recent interest in millimeter-wave lens-based antennas demands high spatial resolution…

The development of innovative terahertz (THz) imaging systems has recently moved in the focus of scientific efforts due to the ability to screen substances through textiles or plastics. The invention of THz imaging systems with high spatial…

Color printing at the diffraction limit has been recently explored by fabricating nanoscale plasmonic structures with electron beam lithography. However, only a limited color range and constant intensity throughout the structure have been…

We present millimeter and sub-millimeter room temperature transmission and loss measurements of 3D printed alumina disc and of a disc with one-sided 3D printed sub-wavelength structures anti-reflection coatings (SWS-ARC). For four bands…

We demonstrate a new approach to classical fiber-fed spectroscopy. Our method is to use a photonic lantern that converts an arbitrary (e.g. incoherent) input beam into N diffraction-limited outputs. For the highest throughput, the number of…

This study presents a prospective concept of a mechanically reconfigurable Gradient Index (GRIN) lens for focusing and beamforming applications. The lens is formed by corrugated layers, each realizing a refractive index profile expressed in…

We establish simple quantitative criterium for the search of new dielectric materials with high values of the refractive index in the visible range. It is demonstrated, that for light frequencies below the band gap the latter is determined…

We present a new spatial-spectral mapping technique permitting to measure the beam intensity at the output of a graded-index (GRIN) multimode fiber with sub-nanometric spectral resolution. We apply this method to visualize the fine…

The symmetry matching between the source and the lens results of fundamental interest for lensing applications. In this work we have modeled an axisymmetric gradient index (GRIN) lens made of rigid toroidal scatterers embedded in air…