Self-assembled tunable photonic hyper-crystals

We have demonstrated a novel artificial optical material, the “photonic hyper-crystal”, which combines the most interesting features of hyperbolic metamaterials and photonic crystals.On the other hand, similar to photonic crystals, hyperbolic dispersion law of extraordinary photons is modulated by forbidden gaps near the boundaries of photonic Brillouin zones.

img2E[1] — Modulation of nanoparticle concentration in magnetic field is much smaller than wavelength (1.5 micron) in IR, where this ferrofluid is hyperbolic

Three dimensional self-assembly of photonic hyper-crystals has been achieved by application of external magnetic field to a cobalt nanoparticle-based ferrofluid. Unique spectral properties of photonic hyper-crystals lead to extreme sensitivity of the material to monolayer coatings of cobalt nanoparticles, which should find numerous applications in biological and chemical sensing.

Similar to hyperbolic metamaterials, photonic hyper-crystals exhibit broadband divergence in their photonic density of states due to the lack of usual diffraction limit on the photon wave vector.

img3[1] — Polarization dependence of transmission spectra is consistent with hyperbolic character of ε tensor

N. Smolyaninova, Bradley Yost, D. Lahneman, E. E. Narimanov, and I. I. Smolyaninov, Scientific Reports (Nature publishing group) 4, 5706 (2014) http://www.nature.com/articles/srep05706

This work was highlighted by SPIE NewsRoom, Laser Focus World , etc.

A video showing formation of photonic hyper-crystal was included in the APS March Meeting 2015 media gallery: http://www.aps.org/meetings/march/vpr/2015/videogallery/index.cfm

Supported in part by NSF grant DMR-1104676