Colloidal superlattices for unnaturally highindex metamaterials at broadband optical frequencies

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


The recent advance in the assembly of metallic nanoparticles (NPs) has enabled sophisticated engineering of unprecedented light-matter interaction at the optical domain. In this work, I expand the design flexibility of NP optical metamaterial to push the upper limit of accessible refractive index to the unnaturally high regime. The precise control over the geometrical parameters of NP superlattice monolayer conferred the dramatic increase in electric resonance and related effective permittivity far beyond the naturally accessible regime. Simultaneously, effective permeability change, another key factor to achieving high refractive index, was effectively suppressed by reducing the thickness of NPs. By establishing this design rule, I have achieved unnaturally high refractive index (15.7 at the electric resonance and 7.3 at the quasi-static limit) at broadband optical frequencies (100 THz ~300 THz). I also combined this NP metamaterial with graphene to electrically control the high refractive index over the broad optical frequencies.

Original languageEnglish
Pages (from-to)28170-28181
Number of pages12
JournalOptics Express
Issue number22
Publication statusPublished - 2015 Nov 2
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015 Optical Society of America.

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


Dive into the research topics of 'Colloidal superlattices for unnaturally highindex metamaterials at broadband optical frequencies'. Together they form a unique fingerprint.

Cite this