Metamaterial research at Aalto University Metamaterial research at Aalto University Aalto University

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Transcript of Metamaterial research at Aalto University Metamaterial research at Aalto University Aalto University

  • Metamaterial research at Aalto

    University

    Aalto University

    School of Electrical Engineering

    Department of Radio Science and Engineering

    Sergei Tretyakov and colleagues

  • Outline

    • University, Department, SMARAD Center of Excellence,

    research group

    • Overview of recent research

    – Electromagnetics of complex media

    – Invisibility and cloaking

    – Isotropic artificial magnetics in the visible

    – Some other topics

  • About myself and my visit to Jena...

    Optics and photonics

    Jena, Germany

    Electromagnetics,

    microwave engineering

    Espoo, Finland

  • Page 4

    Aalto University

    (former Helsinki University of Technology)

    • The oldest and the biggest technical university in Finland – About 15000 students and 250 professors

    • School of Electrical Engineering (former faculty of Electronics, Communications, and Automation)

    • Department of Radio Science and Engineering – Electromagnetics, circuit theory, microwave to terahertz

    techniques (antennas, devices) and measurements, space technology, radio wave propagation, advanced artificial electromagnetic materials

    • Research groups lead by professors

  • About geography

  • There is no such place called ”Aalto”

    • Campuses of the Aalto University are in Espoo and

    Helsinki

  • How it looks like?

  • Aalto is growing:

    SIX Tenure Track PROFESSOR Positions

    The School of Electrical Engineering seeks experts in the following fields:

    • Electrical engineering, Power and energy, Automatic control, Embedded systems, Smart living environment;

    • Radio science and engineering, Radio astronomy, Space science and engineering, Optoelectronics;

    • Communications and networking engineering.

    The positions are open at all levels from assistant professor to full tenured professor.

    Application deadline is September 30, 2012.

  • The RAD department was established in the beginning of 2008 by integrating four laboratories of TKK (TKK is today Aalto University School of Science and Technology), namely Radio Laboratory, Electromagnetics Laboratory, Circuit Theory Laboratory, and Laboratory of Space Technology, into a single unit.

    Personnel:

    – 8 professors

    – Over 20 other researchers with a doctor degree

    – About 30 doctoral students

    – Total number of employees about 100

    RAD department is involved in SMARAD CoE in research selected by the Academy of Finland for 2002–2007 (as Smart and Novel Radios Research Unit) and 2008–2013 (as Finnish Centre of Excellence in Smart Radios and Wireless Research).

    RAD department is also involved in the MilliLab (Millimetre Wave Laboratory of Finland), which has the status of External Laboratory of the European Space Agency (ESA). MilliLab is a joint research institute between Aalto and VTT.

    Department of Radio Science and Engineering (RAD)

    9

  • Page 10

    The Virtual Institute for Artificial Electromagnetic Materials

    and Metamaterials (”Metamorphose VI”) is a non-for-

    profit international association whose purposes are the

    research, the study and the promotion of artificial

    electromagnetic materials and metamaterials.

    About 20 European universities and institutions are members.

    METAMORPHOSE Virtual Institute www.metamorphose-vi.org

  • 6th International Congress

    on Advanced Electromagnetic Materials in

    Microwaves and Optics

    Metamaterials 2012 St. Petersburg, Russia

    17-22 September 2012

    congress2012.metamorphose-vi.org

  • Distributed European Doctoral

    School on Metamaterials

    • Led by Dr. Carsten Rockstuhl, U. Jena

    • www.school.metamorphose-eu.org

    • METAMORPHOSE Virtual Institute

    www.metamorphose-vi.org

  • The next EUPROMETA school

    • Reconfigurable and tunable metamaterials

    – September 21-22, 2012, in conjunction with the

    Metamaterials'2012 Conference

    – St. Petersburg, Russia

  • Artificial electromagnetic materials and applications

    Research group

    4 senior researchers (doctoral degree)

    4 doctoral students

    visitors + undergraduate students

  • Page 15

    Research group: Main current research

    directions

    • Artificial materials (metamaterials) with unusual and extreme

    electromagnetic properties – engineering materials for applications

    • Nano-scale composite materials and artificial surfaces

    • New designs of antennas and microwave devices

    • New designs for terahertz and optical devices (imaging and sensing, nano-

    scale optics...)

    • New applications (cloaks, superlenses, solar cells, thermophotovoltaics...)

  • Classification of electromagnetic

    nanostructured materials

    Not yet

    investigated, but

    possible

    Metawaveguides1D, linear

    nanostructured

    optically dense

    surfaces without

    useful and unusual

    electromagnetic

    properties

    Artificial

    impedance surfaces

    with long inclusions

    or slots

    Plasmonic

    diffraction grids,

    optical band-gap

    surfaces and

    optical frequency

    selective surfaces

    Metasurfaces /

    metafilms

    2D, surface

    Bulk nanostructured

    materials without

    useful and unusual

    electromagnetic

    properties

    Wire media,

    multilayer optical

    fishnet structures,

    alternating solid

    plasmonic and

    dielectric

    nanolayers

    Photonic crystals

    and quasi-

    crystals,

    Optically sparse

    random

    composites

    Bulk MTM of small

    inclusions

    3D, bulk

    Optically dense in

    one direction, while

    either optically

    sparse or with

    extended inclusions

    in other

    direction(s)

    Optically sparse

    (q·a >1) Optically dense

    (q·a1) Optically dense

    (q·a

  • Bianisotropic constitutive relations

    HEB

    HED

    =

    =

    

    

    

    

    j

    j TT

    =

    =

    arbitary,0)j(j :Reciprocal

    real,)j(j :Lossless

    TTTT

    *TTTT*

    

    

    ===

    ==

    (Ari Sihvola)

  • Classification of bianisotropic materials

     

    Symmetric part:

    6 parameters

    (RECIPROCAL)

    Dielectric crystal

    Magnetic medium

    Chiral medium

    Tellegen (Cr2O3)

    Anti- symmetric part

    3 parameters

    (NON- RECIPROCAL)

    Magneto- plasma

    Biased

    ferrite

    Omega medium

    Moving medium

    (Ari Sihvola)

  • Material optimized for the purpose?

    The ”optimal” spiral The resonant frequency (the total length of the wire) is fixed.

    For which shape the particle has the max energy in a given external

    field?

    I.V. Semchenko, S.A. Khakhomov, and A. L. Samofalov, The Optimal Shape

    of a Spiral: Equality of Dielectric,Magnetic and Chiral Properties, NATO

    Advanced Research Workshop META’08, Marrakesh, Morocco, May 7-10, 2008.

  • Page 20

    Optimal metamaterials Chiral media

    ”Optimal” spiral inclusions: n=0, κ=1 – ”extreme parameter values”

    Negative refraction, negative reflection, ”standing spirals”,... S. Tretyakov, I. Nefedov, A. Sihvola, S. Maslovski, C. Simovski, Waves and energy in chiral nihility,

    Journal of Electromagnetic Waves and Applications, vol. 17, no. 5, pp. 695-706, 2003.

    E. Saenz, I. Semchenko, S. Khakhomov, K. Guven, R. Gonzalo, E. Ozbay, S. Tretyakov,

    Modelling of spirals with equal dielectric, magnetic and chiral susceptibilities, Electromagnetics,

    vol. 28, pp. 476–493, 2008.

    I.V. Semchenko, S.A. Khakhomov and S.A. Tretyakov, Chiral metamaterial with unit negative

    refraction index, The European Physical Journal - Applied Physics, vol. 46, no. 3, p. 32607, 2009.

  • Optimal metamaterials for linear polarization Omega media

  • Omega coupling is a very general phenomenon

  • Particle energy (omega particle)

    But for evanescent waves the impedance is imaginary

    and we can optimize the particle shape to maximize the particle energy.

  • Bianisotropic materials optimized for strong interactions with

    electromagnetic fields

  • Total absorption in thin bianisotropic layers

  • Example: Total absorption

    in an omega-layer

  • General approach to design of thin laye