Plasmonic Superlensing in Doped GaAs

Abstract

We demonstrate a semiconductor based broadband near-field superlens in the mid-infrared regime. Here, the Drude response of a highly doped n-GaAs layer induces a resonant enhancement of evanescent waves accompanied by a significantly improved spatial resolution at radiation wavelengths around λ = 20 μm, adjustable by changing the doping concentration. In our experiments, gold stripes below the GaAs superlens are imaged with a λ/6 subwavelength resolution by an apertureless near-field optical microscope utilizing infrared radiation from a free-electron laser. The resonant behavior of the observed superlensing effect is in excellent agreement with simulations based on the Drude-Lorentz model. Our results demonstrate a rather simple superlens implementation for infrared nanospectroscopy.

Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

“…Recent investigations of a GaAs superlens by Fehrenbacher et al 181 have reached similar conclusions about superlens imaging enhancement as in Ref. 172 and Ref.…”

A Local Superlens

“…at the phonon resonances in dielectrics 15,16,17 as well as at the plasmon resonances for metals, 18 semiconductors, 19 or graphene. 20,21 The imaging capabilities of such a lens are not limited by diffraction, however, the optical resolution and the signal contrast are reduced by material absorption and interface roughness.…”

“…15,16,17 Furthermore, these fixed-position superlenses we fabricated by thin-film growth and so far were designed solely in a laterally large-scale fashion. 16,17,19 A Local Superlens by S.C. Kehr et al…”

Эпитаксиальные твердые растворы Al-=SUB=-x-=/SUB=-Ga-=SUB=-1-x-=/SUB=-As : Mg с различным типом проводимости

“…Поэтому огромное количество работ в области физики и тех-нологии полупроводниковых гетероструктур посвящено методам их формирования с использованием средств молекулярно-лучевой и МОС-гидридной эпитаксии [1,2]. Не менее значимыми являются работы по изучению закономерностей легирования эпитаксиальных гетеро-структур на основе соединений группы A III B V , по-скольку высокая производительность оптоэлектронных компонент на их основе может быть обеспечена лишь при условии однозначных представлений о структурных, оптических и энергетических свойствах материалов ге-теропары, а также понимании процессов и закономерно-стей легирования эпитаксиальных твердых растворов ак-цепторными и донорными примесями.…”