TY - JOUR

T1 - Experimental Realization of an Epsilon-Near-Zero Graded-Index Metalens at Terahertz Frequencies

AU - Pacheco-Peña, Victor

AU - Engheta, Nader

AU - Kuznetsov, Sergei

AU - Gentselev, Alexandr

AU - Beruete, Miguel

PY - 2017/9/29

Y1 - 2017/9/29

N2 - The terahertz band has been historically hindered by the lack of efficient generators and detectors, but a series of recent breakthroughs have helped to effectively close the "terahertz gap." A rapid development of terahertz technology has been possible thanks to the translation of revolutionary concepts from other regions of the electromagnetic spectrum. Among them, metamaterials stand out for their unprecedented ability to control wave propagation and manipulate electromagnetic response of matter. They have become a workhorse in the development of terahertz devices such as lenses, polarizers, etc., with fascinating features. In particular, epsilon-near-zero (ENZ) metamaterials have attracted much attention in the past several years due to their unusual properties such as squeezing, tunneling, and supercoupling where a wave traveling inside an electrically small channel filled with an ENZ medium can be tunneled through it, reducing reflections and coupling most of its energy. Here, we design and experimentally demonstrate an ENZ graded-index (GRIN) metamaterial lens operating at terahertz with a power enhancement of 16.2 dB, using an array of narrow hollow rectangular waveguides working near their cutoff frequencies. This is a demonstration of an ENZ GRIN device at terahertz and can open the path towards other realizations of similar devices enabling full quasioptical processing of terahertz signals.

AB - The terahertz band has been historically hindered by the lack of efficient generators and detectors, but a series of recent breakthroughs have helped to effectively close the "terahertz gap." A rapid development of terahertz technology has been possible thanks to the translation of revolutionary concepts from other regions of the electromagnetic spectrum. Among them, metamaterials stand out for their unprecedented ability to control wave propagation and manipulate electromagnetic response of matter. They have become a workhorse in the development of terahertz devices such as lenses, polarizers, etc., with fascinating features. In particular, epsilon-near-zero (ENZ) metamaterials have attracted much attention in the past several years due to their unusual properties such as squeezing, tunneling, and supercoupling where a wave traveling inside an electrically small channel filled with an ENZ medium can be tunneled through it, reducing reflections and coupling most of its energy. Here, we design and experimentally demonstrate an ENZ graded-index (GRIN) metamaterial lens operating at terahertz with a power enhancement of 16.2 dB, using an array of narrow hollow rectangular waveguides working near their cutoff frequencies. This is a demonstration of an ENZ GRIN device at terahertz and can open the path towards other realizations of similar devices enabling full quasioptical processing of terahertz signals.

KW - NEGATIVE INDEX

KW - WAVE-GUIDE

KW - METAMATERIALS

KW - LENS

KW - SUBTERAHERTZ

KW - WAVELENGTHS

KW - TECHNOLOGY

KW - REFRACTION

KW - CHANNELS

KW - DEVICES

UR - http://www.scopus.com/inward/record.url?scp=85030696622&partnerID=8YFLogxK

U2 - 10.1103/PhysRevApplied.8.034036

DO - 10.1103/PhysRevApplied.8.034036

M3 - Article

AN - SCOPUS:85030696622

VL - 8

JO - Physical Review Applied

JF - Physical Review Applied

SN - 2331-7019

IS - 3

M1 - 034036

ER -