A multidirectional cloak for visible light

Abstract

A new macroscopic multidirectional cloak scheme for extraordinary rays is proposed by controlling the optical axes of uniaxial crystals. It eliminates the complicated material constraints and can also be utilized to design a cloaking device for ordinary rays or isotropic cloaks after simplification. Numerical ray tracing and full-wave simulation results validate our design. Moreover, if the uniaxial crystals are changed into other materials whose optical axes can be modulated, like liquid crystals, this scheme has the potential to fabricate direction-tunable cloaks.

Design of open devices based on multi-folded transformation optics

“…Comparing to a traditional cloak device [1,3,[7][8][9][10], the proposed open cloak provides the capability of material or information convertible with the outer world as well as an external cloak [12]. However, it should be noted that the invisibility of an external cloak is greatly depended on a pre-defined position, shape and size of a hidden object while the proposed device is independent of them, which provides a feasible approach to hide a moving object.…”

“…AS an ingenious mathematical approach, transformation optics (TO) [1][2][3][4][5][6] provides a powerful and convenient way to control the electromagnetic (EM) fields arbitrarily, arousing much attentions in the past two decades. Based on this methodology, novel devices with varied functions and applications have been proposed, designed and experimented with an unprecedented prosperity, including invisible cloaks [7][8][9][10][11][12][13], concentrators [14][15][16][17][18], illusory devices [19][20][21][22][23][24][25][26][27][28] and antennas [29][30][31][32][33][34][35] etc. The most striking device among them is invisible cloak, where some properly designed materials are utilized to direct the EM waves propagates smoothly around an arbitrarily shaped object, making the entire device (including the coated object) become invisible for the outside viewers.…”

Design of a magnetically driven current cloak

“…The term metamaterial is commonly used to describe a material engineered in such way [7]. Over the following years, several types of cloaks were reported in the optical [8][9][10][11][12][13] and microwave [14][15][16][17][18] frequency ranges.…”

Surface wave direction control on curved surfaces

“…In the last decades, TO have attracted intensive attention because it enables exotic wave propagation. Broad and fascinating applications have been demonstrated, particularly in controlling the direction of electromagnetic (EM) wave propagation, such as cloaking [4][5][6][7][8][9][10][11], metalens [12][13][14][15], surface wave guides [16][17][18][19][20], absorbers [21] and whispering gallery mode resonators [22].…”