Negative Refraction and Focusing of Circularly Polarized Waves in Optically Active Media

Analysis indicates that certain types of optically active media are capable of producing negative refraction and focusing of circularly polarized waves. It is established that a slab of such material acts just as Veselago’s hypothetical left-handed media lens, providing subwavelength resolution as Sir Pendry’s ideal lens, but for circularly polarized waves.

Figure 1

Geometry of RCP line source in front of a bi-isotropic half-space.

Figure 2

Circularly polarized plane wave transmission and reflection on a bi-isotropic half-space.

Figure 3

Plot of $|U(\overline{x}){|}^2$ in the bi-isotropic medium for $x\in [-{\lambda }_0,{\lambda }_0]$, $y\in [0,3{\lambda }_0]$, due to an RCP line source located in the free space side at ${\overline{x}}_0=(0,-{\lambda }_0)$. Peak transmission occurs at $\overline{x}=(0,{\lambda }_0)$, the expected focal point for an effective index of $-1$. The figure is confirmation of negative refraction, enhancement of evanescent fields, and subwavelength focusing of CP waves in bi-isotropic media. Inset: Ray optics description of the flat bi-isotropic–chiral lens for CP waves ($S=\mathrm{\text{source}}$, $F/F1$ the external/internal focal regions).

Figure 4

Example of Maxwell-Garnett estimate for a random helix composite in low density foam.