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Research Fellowship Opportunity: Optoelectronics and Photonics

General Category: Optoelectronics and Photonics

Advisor: Jimmy Touma Ph.D., Research Physicist, Optoelectronics and Photonics Group, Seekers Branch, AFRL Munitions Directorate

Characterization of Photonic Crystals, Metamaterials, and Metasurfaces

    • The use of an array of periodic subwavelength scatterers as an optical focusing element has been a widely studied phenomenon [1]– [6]. These optical elements designed using these scatterers (meta-atoms) rely mostly on planar elements with thicknesses in subwavelength regimes. Studies have been carried out to quantify the fundamental limits of metasurfaces of these planar elements [7] that show a distinct relationship between the surfaces’ reflected and transmitted fields and their localized phase and polarization control; these findings provide a set of tools and limitations to the design of periodic metasurfaces.
    • The results shown in [7], however, do not consider the cases where the meta-atom is not confined to within the incident wavelength and is not uniform along the direction of propagation. This combination of factors leads to the question of whether a metasurface regime can be supported and maintained for periodic elements that are volumetric in nature. A variation of the refractive index as a function of three-dimensional space can open the possibility of exploring more degrees of freedom to control transmission, reflection, phase, and polarization in a metasurface-based optical element.
    • The proposed idea is to exploit the rapid convergence of numerical optimization methods to explore the fundamental limits of volumetric metasurfaces used to generate optical elements. A concurrent effort will be made to develop a toolset that allows for the design and validation of these metasurfaces with a rapid turnaround while also studying the fundamental relationships between the surfaces’ topology and their transmission, reflection, phase, and polarization control.

Design of Hybrid Nano-Optical Systems

    • AFRL is investigating nano-optical devices, such as metamaterials and photonic crystals, to develop smaller optical systems and better control a wide electromagnetic spectrum band. Our research interests involve developing novel devices utilizing, for example, spatially varying lattices, bio-inspired deformities in photonic crystals, plasmonic/photonic crystal sensors, and hybrid systems that combine metallic (plasmonic) and dielectric metasurfaces. These nano-optical devices can replace traditional optical systems or operate in conjunction with those systems to reduce SWaP without sacrificing performance.

The candidate should have:

  • Conducted research in nano-optics, Plasmonics, and/or metamaterials
  • Strong analytical skills with a modeling and simulation background, such as programming in languages like C/C++, CUDA, Python, or Julia and commercial packages like COMSOL or ANSYS HFSS.
  • Knowledge of raytracing, optical systems design, and characterization (highly desired).

 

References:

[1] T. J. Cui, D. R. Smith, and R. Liu, Metamaterials: Theory, design, and applications. Springer US, 2010. doi: 10.1007/978-1-4419-0573-4.

[2] D. R. Smith, W. J. Padilla, D. C. Vier, S. C. Nemat-Nasser, and S. Schultz, “Composite Medium with Simultaneously Negative Permeability and Permittivity,” 2000.

[3] A. Grbic and G. v. Eleftheriades, “Overcoming the Diffraction Limit with a Planar Left-Handed Transmission-Line Lens,” Phys Rev Lett, vol. 92, no. 11, Mar. 2004, doi: 10.1103/PhysRevLett.92.117403.

[4] L. Verslegers et al., “Planar lenses based on nanoscale slit arrays in a metallic film,” Nano Lett, vol. 9, no. 1, pp. 235–238, Jan. 2009, doi: 10.1021/nl802830y.

[5] N. Meinzer, W. L. Barnes, and I. R. Hooper, “Plasmonic meta-atoms and metasurfaces,” Nat Photonics, vol. 4, no. 11, pp. 748–749, Nov. 2010, doi: 10.1038/nphoton.2010.247.

[6] F. Monticone, N. M. Estakhri, and A. Alù, “Full control of nanoscale optical transmission with a composite metascreen,” Phys Rev Lett, vol. 110, no. 20, May 2013, doi: 10.1103/PhysRevLett.110.203903.

[7] A. Arbabi and A. Faraon, “Fundamental limits of ultrathin metasurfaces,” Sci Rep, vol. 7, Mar. 2017, doi: 10.1038/srep43722

Question? Contact: techtransfer@doolittleinstitute.org

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