Nanoparticle Plasmonics and Metamaterials

Ultrathin Metallic Films

Dynamic & Tunable Metasurfaces

Inverse Design of Nanophotonic Devices

Plasmonic Absorbers

2D Materials

The research program in the Metamaterials and Nanophotonic Devices Lab is mainly focused on the broad area of nanophotonics, an emerging field strategically positioned at the intersection of electrical engineering, applied physics, materials science and nanoscience.

Specifically, we are investigating optical metamaterials, plasmonics, and solid-state nanophotonics to understand the interaction between light and nanoscale photonic materials and to control and manipulate these interactions at will. Our ultimate aim is to design, fabricate and characterize metamaterials and nanophotonic devices with novel optical and photonic functionalities.

  1.   Chad Mirkin, Northwestern

  2.   Vinayak Dravid, Northwestern

  3.   Mark Hersam, Northwestern

  4.   Lincoln Lauhon, Northwestern

  5.   Teri Odom, Northwestern

  6.   Prem Kumar, Northwestern

  7.   Alan Sahakian, Northwestern

  8.   Sridhar Krishnaswamy, Northwestern

  9.   Harry Atwater, Caltech

  10.   Koby Scheuer, Tel Aviv University

  11.   Sefaattin Tongay, Arizona State Univ.

  12.   Junqiao Wu, UC Berkeley

In this research thrust, we investigate exciting optical properties and novel functionalities in artificially engineered materials and surfaces, i.e. metamaterials and metasurfaces. Using electromagnetic simulations, we design unique metasurfaces that control the reflection, transmission and absorption from a surface. Metasurfaces enable flat-optical components such as spectrum splitters, holograms, flat lenses, etc.

Representative Publications:

  1. Z. Li*, E. Palacios*, S. Butun, and K. Aydin, “Visible-frequency metasurfaces for broadband anomalous reflection and high-efficiency spectrum splitting”, Nano Letters, 15, 1615 (2015).

  2. Z. Li, E. Palacios, S. Butun, and K. Aydin, “Ultrawide angle, directional spectrum splitting visible-frequency versatile metasurfaces”, Advanced Optical Materials 4, 953 (2016).

Light-material interactions in 2D Layered materials are extremely weak due to inherent one-to-few atom thicknesses of such thin materials. We investigate nanophotonic light trapping and photon management mechanism to increase light-matter interactions. In particular we are interested in increasing light emission and absorption for practical solar cell, photodetector and LED applications. We are also utilizing 2D materials as alternative plasmonic materials for infrared wavelengths.

Representative Publications:

  1. S. Butun, S. Tongay and K. Aydin, “Enhanced light emission from large-area monolayer MoS2 using plasmonic nanodisc arrays”, Nano Letters, 15, 2700 (2015).

  2. Z. Liu, and K. Aydin, “Localized surface plasmons in nanostructured monolayer black phosphorus”, Nano Letters 16, 3457 (2016).

Optical losses in metals are often considered as the biggest disadvantage of plasmonics field. In this research area, we are benefiting from the lossy behavior of metals to design spectrally selective super and perfect absorbers using resonant plasmonic nanostructures. Controlling the absorption spectra by design will enable unique spectrally selective absorbers that can be utilized in thermophotovoltaics, thermal emitters, absorption filters, biosensors and hot-electron collection devices.

Representative Publications:

  1. K. Aydin, V. E. Ferry, R. M. Briggs, and H. A. Atwater, “Broadband, polarization-independent resonant light absorption using ultrathin plasmonic super absorbers”, Nature Communications 2, 517 (2011).

  2. Z. Li, S. Butun and K. Aydin, “Ultra-narrow band absorbers based on surface lattice resonances in nanostructured metal surfaces”, ACS Nano 8, 8242 (2014).

Conventional optical devices are designed using handful parameters such as size and periodicity of nanostructures in photonic crystals, radius of microdisk resonators, width of waveguides, etc. Inverse-design is a new paradigm enabling us to tap into vast parameter space for designing exciting photonic and optical devices. We utilize objective-first method and convex-optimization techniques to design ultra-compact on-chip and free-space optical components.

Representative Publications:

  1. F. Callewaert, S. Butun, Z. Li, and K. Aydin, “Inverse design of an ultra-compact broadband optical diode based on asymmetric spatial mode conversion” Scientific Reports 6, 32577 (2016).

  2. K. Aydin, “Nanostructured Silicon Success” Nature Photonics 9, 953 (2015).

Most of the nanophotonic devices are passive, lacking the ability to dynamically control light-matter interactions. Active and dynamic nanopotonic devices enable to tune, manipulate, control optical functionalities using an external stimulus. We combine phase-transition materials with metasurfaces in order to induce temperature dependent changes in the optical properties of the hybrid nanophotonic materials and enable active control of reflection, absorption and transmission of infrared radiation.

Representative Publications:

  1. H. Kocer, S. Butun, E. Palacios, Z. Liu, S. Tongay, D. Fu, K. Wang, J. Wu, and K. Aydin, “Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered films” Scientific Reports 5, 13384 (2015).

  2. H. Kocer, S. Butun, B. Banar, K. Wang, S. Tongay, J. Wu, and K. Aydin, “Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered films” Applied Physics Letters 106, 161104 (2015).

Bulk metals are reflective and used as mirrors in optical devices. Utilizing optically thin metals (5-30 nm) below their skin depth in Fabry-Perot type cavities, we design and realize large-area color filters, perfect absorbers, and omni-directional broadband absorbers. These ultrathin metallic films are easy to fabricate via common material deposition tools and does not require expensive nanofabrication methods.

Representative Publications:

  1. Z. Li, S. Butun, and K. Aydin, “Large-area, lithography-free super absorbers and color filters at visible frequencies using ultratin metallic films” ACS Photonics 2, 183 (2015).

  2. Z. Li, H. Kocer, and K. Aydin, “Omnidirectional, broadband light absorption using large-area, ultrathin lossy metallic film coatings” Scientific Reports 5, 15137 (2015).

Metasurfaces and metamaterials are usually fabricated using top-down fabrication apporaches followed by metal deposition resulting in rough, non-crystalline metals. On the other hand, metal nanoparticles can be synthesized as a single crystal. In collaboration with Mirkin group in the Chemistry department, we are investigating nanoparticle based two-dimensional metasurfaces and three-dimensional metamaterials. We utilize DNA-assembly to construct 2D and 3D nanoparticle lattices with exciting optical properties.

Representative Publications:

  1. Z. Li, S. Butun, and K. Aydin, “Touching gold nanoparticle chain based plasmonic antenna arrays and metamaterials” ACS Photonics 1, 228 (2014)

  2. Q.-Y. Lin, Z. Li, K. A. Brown, M. N. O’Brien, M. B. Ross, Y. Zhou, S. Butun, P.-C. Chen, G. C. Schatz, V. P. Dravid, K. Aydin, and C. A. Mirkin, ”Strong coupling between plasmonic gap modes and photonic lattice modes in DNA-assembled gold nanocube arrays” Nano Letters 15, 4699 (2015).


Metamaterials & Metasurfaces


Metamaterials & Nanophotonic Devices Laboratory
AYDIN Research Group

Metamaterials and Nanophotonic Devices Laboratory

Northwestern University