Flat optics, which could planarize and miniaturize the traditional optical elements, possesses the features of extremely low profile and high integration for advanced manipulation of light. Here we proposed and experimentally demonstrated a planar metalens to realize an ultra-long focal length of ~240λ with a large depth of focus (DOF) of ~12λ, under the illumination of azimuthally polarized be...

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 practical artificial materials. Here we show that by spatially grading in the plane of the mesh we can manufacture a Graded Index (GrIn) thin flat lens optimize...

Abstract—Flat left-handed metamaterial (LHM) lens can generate appropriate focusing spot in biological tissue as required in microwave tumor hyperthermia treatment. By using single flat LHM lens to concentrate microwave in a mass of tissue covered by water bolus, microwave hyperthermia scheme is proposed for superficial tumor hyperthermia. The power distribution in tissue is simulated by finite...

Since liquid crystal (LC) was proposed for making a tunable lens, the LC based zoom lens has been studied extensively for machine vision, photonics, information processing and eye glasses. Various approaches for making LC tunable lenses exists. Among them three methods are presented in this seminar: flat LC spherical lenses, microlenses made of nanosized polymer dispersed LC and Fresnel type sw...

In this paper we study how the statistical properties of gravitational lenses are modified when galaxy evolution is taken into account. We consider models of the universe in which the cosmological term Λ decreases with time or remains constant, both with and without the evolution of galaxies. We show that the probability of a beam encountering a lens event (lens optical depth) for a source at z...

The complex 10-component gravitational lens B1933+503 has been monitored with the VLA during the period February to June 1998. Here we present the results of this A-configuration 8.4 GHz monitoring campaign. The 37 epochs of observations have an average spacing of 3 days. The data have yielded light curves for the four flat-spectrum radio components (components 1, 3, 4 and 6). We find no signif...

We report on an electrically controlled liquid-crystal-based variable optical lens filled with a dual-frequency nematic material. The lens design employs a hole-patterned electrode structure in a flat nematic cell. In order to decrease the lens switching time we maximize the dielectric torque by using a dual-frequency nematic material that is aligned at an angle approximately 45 degrees with re...

We estimate the dust extinction laws in two intermediate redshift galaxies. The dust in the lens galaxy of LBQS 1009–0252, which has an estimated lens redshift of zl ≃ 0.88, appears to be similar to that of the SMC with no significant feature at 2175Å. Only if the lens galaxy is at a redshift of zl ≃ 0.3, completely inconsistent with the galaxy colors, luminosity or location on the fundamental ...

An essential impact which can improve the indoor environment and save on power consumption for artificial lighting is utilization of daylight. Optical fiber daylighting technology offers a way to use direct daylight for remote spaces in a building. However, the existing paradigm based on the precise orientation of sunlight concentrator toward the Sun is very costly and difficult to install on t...

In earlier time, we proposed a flat LHM-based hyperthermia scheme for conformal hyperthermia of a large superficial tumor. It is demonstrated that in this scheme by deploying multiple microwave sources in a specific array to shape the heating zone and properly setting the source-to-lens distance or phases of sources to adjust the inclination of heating zone, a heating zone better fit to large s...