A frequency-tunable cloak with semiconducting constituents

Abstract

A frequency-tunable cloak with semiconducting constituents has been proposed by modifying the dielectric constant by externally controlling the free-carrier density. We have theoretically studied that the cloaking frequency of a single-layer shell consisting of intrinsic InSb can be tuned by varying the temperature based on the Mie scattering theory. The calculated results show that this tunable cloak has a large bandwidth of over 0.3 THz, a tunability of cloaking frequency of 17 GHz K−1 with temperature and a dramatic reduction in the total scattering cross section of 90% at cloaking frequencies. It is also possible to realize a tunable cloak of extrinsic semiconductor Ge by changing the impurity density with current injection.

Invisibility and Cloaking Based on Scattering Cancellation

“…Active materials and non‐Foster surfaces may further broaden the reach of cloaking technology by breaking fundamental limits, based on passivity and causality, in terms of bandwidth of operation. Besides, adding nonlinear loads, such as nonlinear optical materials or RF diodes, varactors and transistors, may enable tunable and switchable cloaking, which has been theoretically proposed for scattering‐cancellation‐based cloaks 114, 147–149…”

Tuning Plasmonic Cloaks with an External Magnetic Field

“…As a result, if there is a need to modify the operation frequency band it is usually necessary to engineer a new device, with different geometric parameters and materials, limiting its applicability [6]. To circumvent this limitation, some proposals of tunable cloaks have been developed [17][18][19]. One of them is to introduce a nonlinear layer in multi-shell plasmonic cloaks, so that the scattering cross-section can be controlled by changing the intensity of the incident EM field [18].…”

Syntheses and crystal structures of bis(4-methylpyridine-κN)bis(selenocyanato-κN)zinc(II) and catena-poly[[bis(4-methylpyridine-κN)cadmium(II)]-di-μ-selenocyanato-κ2 N:Se;κ2 Se:N]

“…It is also noted that several Cd(NCSe) 2 chain compounds are reported in the CSD, but in all of them the Cd cations show an all-trans coordination and are linked into linear chains [BIWTOR (Fettouhi et al, 2008), DAYWAE (Sadhu et al, 2017), DOJBEK (Choudhury et al, 2008), FAPGAG , FIMJIW (Werner et al, 2013), NAQXIO (Boeckmann, Jess et al, 2011), OLOZAQ (Li & Liu, 2003), OWOHOY , QIPYAP (Secondo et al, 2000) and ZANQAI (Werner et al, 2012)].…”