* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Applied Electromagnetics
Optical flat wikipedia , lookup
Ellipsometry wikipedia , lookup
Nonimaging optics wikipedia , lookup
Optical amplifier wikipedia , lookup
Optical aberration wikipedia , lookup
Fiber-optic communication wikipedia , lookup
Optical rogue waves wikipedia , lookup
Surface plasmon resonance microscopy wikipedia , lookup
Magnetic circular dichroism wikipedia , lookup
Terahertz metamaterial wikipedia , lookup
3D optical data storage wikipedia , lookup
Harold Hopkins (physicist) wikipedia , lookup
Photon scanning microscopy wikipedia , lookup
Optical coherence tomography wikipedia , lookup
Interferometry wikipedia , lookup
Passive optical network wikipedia , lookup
Optical tweezers wikipedia , lookup
Silicon photonics wikipedia , lookup
Applied Electromagnetics Silvio Hrabar Faculty of Electrical Engineering and Computing, University of Zagreb, Croatia The Course Structure Part I Artificial electromagnetic materials Part I Metamaterial-based guiding structures Part III Metamaterial-based antennas and scatterrers Part IV Active Metamaterials Part V New directions Part V New directions in Metamaterials • Going optical (From RF to ‘plasmoncs’) • Going nano (From electronics to ‘metatronics’) • Going ‘carbonical’ (From CNT to graphene) • Going beyond electromagnetics (from acoustics to black holes) • Conclusions Going optical (From RF to ‘plasmoncs’) Going Optical – Approach I Scaling Down the Size of Inclusions Going Optical – Approach II Make Use of Surface Plasmons The Lycurgus Cup (glass; British Museum; 4th century A. D.) Going Optical – A ‘Soft’ Approach Make Use of Surface Plasmons Permittivity of silver Thesurfaceplasmonresonance Metallicsphereembeddedindielectrichost: Eo εεinin absorption (a. u.) ε0 electron sphere 10 9 8 7 6 5 Ag + SiO2 Au + SiO2 Cu + SiO2 4 3 2 1 200 400 600 wavelength /nm 800 Theplasmonicresonanceofa nano‐sphere low frequency high frequency Localfieldinsidethesphere: Ein 3ε0 E0 εin 2ε0 Resonancecondition: ε i +2ε 0 0 •Waveguiding Applications in Optical Regime •M. Quinten et. al. ‘Electromagnetic energy transport via linear chains of silver nanoparticles’ (Optics Letters, Vol. 23, No. 17, 1998) •S. Maier, P.G. Kik, H.A. Atwater, ‘Optical Pulse Propagation in Metal nanoparticle Chain Waveguides’ (Phys. Rev. B , 2003) •L •T •T •All figures copied from the original articles Other potential applications in optical domain 1D Backward-wave and plasmonic Forward-wave Nano-transmission lines and nano-antennas Alu and Engheta; JOSA B, March 2006 Non-plasmonic 2 D Backward-wave and Forward-wave ‘flatland’ structures (e.g. super lenses) Backward-wave and forwardwave 3 D metamaterials ;Alu and Engheta, Phys. Archive 2006 Ensembles of plasmonic nanospheres at optical frequencies and a problem of negative index behavior E.V. Ponizovskaya and A.M. Bratkovsky http://arxiv.org/abs/cond-mat/0701186v1 (2007) New Idea - Scaled RF Replicas of Plasmonic Structures What is electrical engineering interpretation of a plasmonic (i.e. ENG ) nano-sphere (Engheta et. al. IWAT 2005) P P How to obtain the negative electric polarizabilty using a simple inclusion in RF and microwave regime ? real part εr R C Einc Z Es ca t V=L o ef E in Za + Z Imaginary L 0 part 1 0 I f0 f pmp f •D.R. Smith et. al. :‘Loop-wire medium for investigating plasmons at microwave frequencies’, App. Phys. Lett., Vol 75, No. 10, 1999 ) An ideal ENG sphere H. A. Wheeler, “Fundamental limitations of small antennas,” Proc. IRE, vol. 35, pp. 1479–1484, 1947 H. A. Wheeler, “The spherical coil as an inductor, shield, or antenna,” Proc. IRE, vol. 46, pp. 1595–1602, 1958 S. R. Best, “The radiation properties of electrically small folded spherical helix antennas,” IEEE Trans. Antennas Propag., vol. 52, pp.953–960, 2004 An ideal ENG sphere H Ein I Prototyping of ‘RF replicas’ of plasmonic spheres (Hrabar et.al., IEEE AP-S, 2007) diameter = 5.8 cm Best’s spherical resonator Simulated E-field distribution Measurement of E-field phase distribution along four-sphere chains (RF replicas of plasmonic WG) 0 1 20 -100 Phase[degrees] L Measuring points FW -200 -300 -400 -500 0 solid: simulated; dashed: measured 5 10 15 20 Measuring point Phase[degrees] 400 T 1 Measuring points 20 300 solid: simulated; dashed: measured 200 BW 100 0 0 5 10 Measuring point 15 20 Full-wave simulation of the electric field distribution along the chain (T polarization) How to test a phase reversal of E field ? (Hrabar et.al. Nanometa 2009) f0~208 MHz, diameter~18 cm (~0.12λ) Measurement of the phase of S21 Point 1 Point 2 Incoming plane wave It is difficult to assure a plane wave illumination ! Phase 2-phase 1= 192 degrees Measurement using a quasi static excitation with homogenous E-field (d = 20 cm, f=150 MHz) Parallel plate capacitor Spherical resonator Parallel plate capacitor Linear taper Linear taper Best’s spherical resonator Balun Imaginary 0 part 1 0 f0 f pmp f x Phase difference[degrees] εr x 180 real part x x simulations 120 measurements 60 x 0 0.05 x 0.1 0.15 0.2 0.25 Frequency[GHz] x 0.3 x 0.35 0.4 D H J , t •This ‘nano-cluster’ is actually a SRR with circulating displacement current ! •Is it possible to construct an RF analog of ‘plasmonic circular cluster ’? •Not fully, due to inherent anisotropy of RF replicas of plasmonic nano – spheres… •But, it should be possible to experimentally prove the basic principle ! How to test an RF analog of ‘plasmonic circular cluster ‘? Subwavelength SRR-based Waveguide •(Marques et.al. 2002, Hrabar et.al. 2003) Transmission coefficient[dB] 0 -10 -20 -30 -40 -50 -60 -70 -80 0.45 0.5 0.55 0.6 Frequency[GHz] 0.65 0.7 •Animation of simulated distributions of x-oriented component of the magnetic field at 484 MHz •RF •c •Feeding waveguide •Collections of four Best's resonators •Feeding waveguide •Is it possible to construct isotropic RF analog of ‘plasmonic nanosphere ‘? •Prototyping and measurement of isotropic •RF analog of ‘plasmonic nanosphere ‘ •0 degrees (x and y) •45 degrees (x ) •45 degrees (y ) Near-field Superlens E H J t H E t Near-field Superlens Experimentally achieved images N. Fang, H. Lee, C. Sun, X. Zhang, Science 308, 534, (2005). written object (top) optical image (center) optical image without super- lens Problem 2 All these structures have significant loss ! What could be an appropriate gift for tenth birthday? n’/n’’=8 Going nano (From electronics to ‘metatronics’) Presentation slide by N. Engheta Presentation slide by N. Engheta Presentation slide by N. Engheta Presentation slide by N. Engheta Presentation slide by N. Engheta Presentation slide by N. Engheta Scaled prototype of optical D-dot wire (Muha, Hrabar et al. 2011) • Going ‘carbonical’ (From CNT to graphene) Carbon Nano-tubes (CNT) Graphene-based One-atom-thick Metamaterials Figures taken from N. Engheta presentation slides Graphene-based Metamaterials Figures taken from N. Engheta presentation slides Going beyond electromagnetics (from acoustics to black holes) (Shu Zhang, Ph.D. thesis) 2005) Acoustic TL metamaterial (Shu Zhang, Ph.D. thesis) 2005) Acoustic TL cloak What’s next? • Nanotechnology + metamaterials (plasmonics, ,photonics, lasing, gain materials, superluminal materials, graphene, nano-spheres and nanofilms) • One might not have all necessary technology in nano-science, but basic physical principles and ideas surely can be verified with minimal investment