Metamaterial photonic funnels for subdiffraction light compression and propagation

We present waveguides with photonic crystal cores, supporting energy propagation in subwavelength regions with a mode structure identical to that in telecom fibers and develop an analytical description of light transmission through these systems. We design metamaterials for near-, mid-, and far-IR frequencies, and demonstrate $\sim 10\cdots 30\%$ energy transfer to and from regions smaller than $1∕25\text{th}$ of the wavelength via the numerical solution of Maxwell equations. Both positive- and negative-refractive index light transmissions are shown. Our approach, although demonstrated here in circular waveguides for some specific frequencies, is easily scalable from optical to IR to THz frequency ranges, and can be realized in a variety of waveguide geometries. Our design may be used for ultra high-density energy focusing, nm-resolution sensing, near-field microscopy, and high-speed photonic computing.