Ray optics at a deep-subwavelength scale: a transformation optics approach.

We present a transformation optics approach for molding the light flow at the deep-subwavelength scale, using metamaterials with uniquely designed dispersion. By conformal transformation of the electromagnetic space, we develop a methodology for realizing subwavelength ray optics with curved ray trajectories. This enables deep-subwavelength-scale beams to flow through two- or three-dimensional spaces.