Manipulating complex light with metamaterials

Abstract

Recent developments in the field of metamaterials have revealed unparalleled opportunities for "engineering" space for light propagation; opening a new paradigm in spin- and quantum-related phenomena in optical physics. Here we show that unique optical properties of metamaterials (MMs) open unlimited prospects to "engineer" light itself. We propose and demonstrate for the first time a novel way of complex light manipulation in few-mode optical fibers using optical MMs. Most importantly, these studies highlight how unique properties of MMs, namely the ability to manipulate both electric and magnetic field components of electromagnetic (EM) waves, open new degrees of freedom in engineering complex polarization states of light at will, while preserving its orbital angular momentum (OAM) state. These results lay the first steps in manipulating complex light in optical fibers, likely providing new opportunities for high capacity communication systems, quantum information, and on-chip signal processing.

Figure 1

(a) The SEM image of magnetic metamaterial covering the core of the fiber (shown by a solid line); (b) Schematic cross-section of two metamagnetic nanostrips consisting of a Ag-LiF-Ag multilayer on silica fiber as a substrate, incoming light k, E, and H fields orientation is also shown for the cases of TE and TM linearly polarized light; TW-top width, BW-bottom width; (c) Schematic of transmission spectra for TE and TM polarization; (d) Schematic of metamagnetic structure illuminated with light linearly polarized at an angle to the grating axes.

Figure 2

(a) The schematic of the setup for generation of a radially polarized vortex beam; (b)–(c) The SEM images of the concentric rings pattern on fiber covered with 200 nm thick Ag layer, such that the patterned area had a pitch/period ratio of 100 nm/200 nm; (d) Calculated intensity and polarization distribution of the resulting beam; (e) Measured intensity profile of the generated radially polarized vortex beam; (f) Measured interference pattern resulting from overlapping the generated vortex beam with a spherical reference beam.

Figure 3

(a) The schematic of the experimental setup to study radially polarized vortex beam interaction with the magnetic MM; (b) and (c) Calculated intensity profiles at the output for the cases of off- and on-resonance propagation, respectively; (d) and (e) Measured intensity profiles at the output for the cases of off- and on-resonance propagation, respectively.

Figure 4. Calculated (Modeling) and measured (Exp.) evolution of intensity profiles and instantaneous local polarization direction (numerical simulations) of an initially radially polarized vortex beam after its interaction with the magnetic metamaterial off- (left) and on- (right) magnetic resonance with a polarization analyzer inserted between the fiber with MM and a CCD camera.