Abstract
Although a lot of progress has been made in the field of integrated photonics, the integration density of photonic integrated
circuits remains much lower than their electronic counterparts, mainly limited by an inherent wavelength condition
on the size of their constituents. Only recently, researchers have tried to overcome this wavelength condition, e.g., by
the use of plasmonics and left-handed materials. In this contribution, we want to present a waveguide - an essential
component in photonic circuits - that has the possibility of confining light in a waveguide with sub-wavelength diameter
[Appl. Phys. Lett. 92, 203111, 2008]. This waveguide uses a left-handed material in order to control the phase
evolution of an optical mode during propagation through the waveguide. We calculate the contributions to this phase shift
from the optical path length and from the reflections at the cladding interface and we show that the control of this phase
shift by a left-handed material allows for tailoring the properties of the optical modes. From the calculated mode profile
and dispersion relation, we show that the proposed geometry allows for waveguides with a thickness that is at least one
order of magnitude smaller than the optical wavelength. This miniaturization does not inversely affect the confinement
properties of the propagating modes, i.e., the optical mode diameter remains comparable to the waveguide thickness and
the light does not extend far into the cladding.
