Theory and Experiment of Isotropic Electromagnetic Beam Bender Made of Dielectric Materials

In this paper, we utilize the deformation transformation optics (DTO) method to design electromagnetic beam bender, which can change the direction of electromagnetic wave propagation as desire. According to DTO, the transformed material parameters can be expressed by deformation tensor of the spatial transformation. For a beam bender, since the three principal stretches at each point induced by the spatial transformation are independent to each other, there are many possibilities to simplify the transformed material parameters of the bender by adjusting the stretches independently. With the DTO method, we show that the reported reduced parameters of the bender obtained by equivalent dispersion relation can be derived as a special case. An isotropic bender is also proposed according to this method, and it is fabricated by stacking dielectric materials in layered form. Experiments validate the function of the designed isotropic bender for a TE wave; it is also shown that the isotropic bender has a broadband with low loss, compared with the metamaterial bender. The isotropic bender has much easier design and fabrication procedures than the metamaterial bender.

[1]  David R. Smith,et al.  Design of electromagnetic cloaks and concentrators using form-invariant coordinate transformations of Maxwell’s equations , 2007, 0706.2452.

[2]  Willie J Padilla,et al.  Guiding light with conformal transformations. , 2009, Optics express.

[3]  Gengkai Hu,et al.  Nonsingular two dimensional cloak of arbitrary shape , 2009, 0904.2942.

[4]  T. Cui,et al.  Arbitrary bending of electromagnetic waves using realizable inhomogeneous and anisotropic materials. , 2008, Physical review. E, Statistical, nonlinear, and soft matter physics.

[5]  David R. Smith,et al.  Broadband Ground-Plane Cloak , 2009, Science.

[6]  U. Leonhardt.  Optical Conformal Mapping , 2006, Science.

[7]  Matti Lassas,et al.  On nonuniqueness for Calderón’s inverse problem , 2003 .

[8]  T. Cui,et al.  Arbitrary bending of electromagnetic waves using isotropic materials , 2009 .

[9]  David R. Smith,et al.  Metamaterial Electromagnetic Cloak at Microwave Frequencies , 2006, Science.

[10]  David R. Smith,et al.  Controlling Electromagnetic Fields , 2006, Science.

[11]  David R. Smith,et al.  Optical design of reflectionless complex media by finite embedded coordinate transformations. , 2007, Physical review letters.

[12]  G. Hu,et al.  Design method for quasi-isotropic transformation materials based on inverse Laplace's equation with sliding boundaries. , 2009, Optics express.

[13]  Huanyang Chen,et al.  Transformation media that rotate electromagnetic fields , 2007, physics/0702050.

[14]  J. Willis,et al.  On cloaking for elasticity and physical equations with a transformation invariant form , 2006 .

[15]  G. Hu,et al.  Design method for electromagnetic cloak with arbitrary shapes based on Laplace's equation. , 2008, Optics express.

[16]  J. Pendry,et al.  Transformation-optical design of adaptive beam bends and beam expanders. , 2008, Optics express.