Fundamentals applications of Lecture 22 plasmonics Svetlana V

Fundamentals & applications of Lecture 2/2 plasmonics Svetlana V. Boriskina

Overview: lecture 2 • Recap of Lecture 1 • Refractive index sensing • SP-induced nanoscale optical forces – Optical trapping & manipulation of nano-objects • • • Fluorescence & Raman spectroscopy Plasmonics for photovoltaics Hydrodynamic design of plasmonic components Magnetic effects Thermal effects: – Plasmonic heating – Near-field heat transfer via SPP waves • Plasmonic photosensitization of materials • Further reading & software packages • Omitted topics S. V. Boriskina, 2012

Drude-Lorentz-Sommerfeld theory Plasma frequency Drude permittivity function: Image credit: Wikipedia Collision frequency electron velocity S. V. Boriskina, 2012 mean free path

Recap of Lecture 1: Propagating waves Frequency Plane wave transverse Bulk plasmon longitudinal Surface plasmon TM: E=(Ex, 0, Ez) S. V. Boriskina, 2012 (Quasi) particle Dispersion equation ω photon plasmon metals: semicond. : polariton = photon + plasmon kx(ω) High DOS, high localization

Recap of Lecture 1: Localized plasmons Scattering response quadrupole E dipole -- +++ Movie: http: //juluribk. com dimer heptamer Plasmonic molecules Plasmonic antenna array S. V. Boriskina, 2012 Near-field patterns λ Lowest-energy modes High DOS, high localization Plasmonic atom Schematic dipoles

Plasmons interactions with matter • Optical – Extreme light focusing/localization (sub-resolution imaging, photovoltaics) – Strong sensitivity to environmental changes (sensing) – Amplification of weak molecular signals (fluorescence, Raman scattering, absorption, circular dichroism) • Electronic – Enhancement of catalytic reactions – Plasmonic photosensitization of materials • Mechanical – Mechanical manipulation of nanoobjects • Thermal – Selective heating of nanoscale areas – Enhanced near-field heat transfer S. V. Boriskina, 2012

SP-enhanced sensing LSP sensors SPP sensors Mc. Farland, A. D. & R. P. Van Duyne, Nano Lett. 2003. 3(8): p. 1057 -1062. Sensor figure of merit (Fo. M): Sensitivity http: //www. bio-sensors. net Requirements: • High sensitivity • High spectral resolution • Compact design S. V. Boriskina, 2012 Resonance linewidth

FOM enhancement & miniaturization • Fano resonances in plasmonic molecules Mirin, N. A. , K. Bao, & P. Nordlander, J. Phys. Chem. A, 2009. 113(16): p. 4028 -4034. S. V. Boriskina, 2012

Towards single-molecule sensitivity Hybrid modes in optoplasmonic molecules: S. V. Boriskina, 2012 Santiago-Cordoba, M. A. et al, Appl. Phys. Lett. , 2011. 99: p. 073701. Also: Boriskina, S. V. & B. M. Reinhard, Opt. Express, 2011. 19(22): 22305 -22315; Ahn, W. et al, ACS Nano, 2012. 6(1): 951 -960.

Raman spectroscopy Rayleigh scattering Dipole moment induced by light: hν 0 polarizability tensor Raman scattering vibrational coordinate hν 0 h(ν 0 ± νm) νm - molecular fingerprint excited Rayleigh Raman (Stokes & anti-Stokes) hν 0 virtual (induced dipole) hνm particle size a very weak effect! S. V. Boriskina, 2012 Rayleigh vibrat. ground Stokes Raman – Nobel Prize in 1930

Surface enhanced Raman spectroscopy (SERS) @ the molecule position! E-field enhancement @ ν 0 E-field enhancement @ (ν 0 –νm) High field localization enables SERS fingerprinting of single molecules R 6 G molecules on Ag nanoparticles Nie, S. & S. R. Emory, Science, 1997. 275(5303): 1102 -1106. Fleischman M, et al Chem. Phys. Lett. 1974; 26: 123. S. V. Boriskina, 2012 Jeanmaire DL, Duyne RPV. J. Electroanal. Chem. 1977; 84: 1. Review: Moskovits, M. , J. Raman Spectr. , 2005. 36(6 -7): p. 485 -496 +references therein

Single molecule delivery to the SP hot spot • super-hydrophobic delivery: De Angelis, F. , et al. Nat Photon. 5(11): p. 682 -687. S. V. Boriskina, 2012

Single molecule delivery to the SP hot spot • Optical trapping: Gradient force Dissipative force The probability to find a molecule @ r : Intensity enhancement Optical potential Stable trapping: Review: Juan, M. L. et al, Nat Photon, 2011. 5(6): p. 349 -356 S. V. Boriskina, 2012 L. Novotny, et al, Phys. Rev. Lett. 79 (4), 645 (1997); H. Xu and M. Käll, Phys. Rev. Lett. 89 (24), 246802 (2002).

SP-enhanced fluorescence Fluorescence rate of a dipole with moment μ: hνexc excitation rate radiative rate Excitation rate: hνf non-radiative rate (resistive heating) Spacer is needed to avoid quenching Fermi’s golden rule: Local density of states The emission intensity affected by both the excitation & emission modification S. V. Boriskina, 2012 Anger, P. Bharadwaj & L. Novotny, Phys. Rev. Lett. , 2006. 96(11): p. 113002

SP-enhanced fluorescence Single-molecule fluorescence Emission spectrum shaping by the high -LDOS nanoparticle resonances Kinkhabwala, A. , et al. Nature Photon. , 2009. 3(11): p. 654 -657. Russell, K. J. , et al. , Nat Photon, 2012. advance online publication. S. V. Boriskina, 2012 See also a review: Ming, T. , et al. , J. Phys. Chem. Lett. 3(2): p. 191 -202 (2012).

Plasmonic solar cells optical absorption c-Si: 250 - 700 μm a-Si: 0. 1 – 0. 3 μm charge carrier diffusion H. Atwater & A. Polman, Nature Mater. 2010 Electronic/photonic lengths mismatch S. V. Boriskina, 2012

Efficient nanoscale light trapping increase of the local density of optical states in a certain frequency range Callahan et al, Nano Lett. 2012 scattering field enhancement waveguiding Atwater & Polman, Nature Mater. 2010 S. V. Boriskina, 2012

How can a particle absorb more than the light C. F. Bohren, Am J. Phys. 1983, 51(4), p. 326 incident upon it? Poynting vector determines electromagnetic power flow W. Ahn, S. V. Boriskina, et al, Nano Lett. 12, 219 -227 (2012) extinction cross-section S. V. Boriskina, 2012 powerflow saddle point

Optical energy flows in the direction of the phase change group velocity phase saddle phase vortex flow saddle flow vortex Local topological features (sources, saddle points, vortices & sinks) define phase S. V. Boriskina, 2012 landscape that governs optical power flow W. Ahn, et al, Nano Lett. 12, 219 -227 (2012) vortex nanogear transmission

Reconfigurable vortex transmissions S. V. Boriskina, 2012 S. V. Boriskina & B. M. Reinhard, Nanoscale, 4, 76 -90, 2012

Reconfigurable vortex transmissions: vortex nanogates ‘… the title is straight out of Enterprise's engineering room’ Next. Big. Future. com Sci. Tech forum S. V. Boriskina, 2012 Physical picture behind vortex nanogate

Hydrodynamic design of SP components Electromagnetics Fluid dynamics ? Maxwell’s equations: Gauss’ law for magnetism Navier-Stokes equations: Continuity (mass conservation) equation Faraday’s law Ampere’s law + boundary conditions S. V. Boriskina, 2012 Momentum conservation equation fluid density flow velocity

Hydrodynamic form of Maxwell’s equations Madelung transformation: material loss or gain ‘Photon fluid’ density: ‘mass’ conservation: ‘Photon fluid’ velocity: momentum conservation: convective term • steady state flow • local convective acceleration possible • fluid flux (the momentum density): S. V. Boriskina, 2012 external potential created by the nanostructure S. V. Boriskina & B. M. Reinhard, Nanoscale, 4, 76 -90, 2012

Hydrodynamic form of Maxwell’s equations Vortex generates a velocity field: S. V. Boriskina, 2012 S. V. Boriskina & B. M. Reinhard, Nanoscale, 4, 76 -90, 2012

Energy flows in plasmonic nanostructures Stockman’s nanolens: Li, K. , M. I. Stockman, & D. J. Bergman, Phys. Rev. Lett. , 2003. 91(22): p. 227402. S. V. Boriskina & Reinhard, Nanoscale, 4, 76 -90, 2012 Surface plasmon polariton wave: S. V. Boriskina, 2012

Magnetic SP effects coil magnet Plasmonic nanostructures built from nonmagnetic materials can exhibit effective magnetic permeability Split-ring resonator: Image: http: //www. ndt-ed. org/ double-negative metamaterials effective permeability Pendry, J. B. et al, IEEE Trans. Microw. Theory Tech. , 47(11), p. 2075, 1999 rotating currents in the rings induce magnetic flux S. V. Boriskina, 2012 Shelby, R. A. , et al Science, 2001. 292(5514): p. 77 -79.

Magnetic SP effects in nanoparticle clusters Anti-ferromagnetic response: charge density: Magnetic dipole induced magnetic moments: Liu, N. , et al. , Nano Letters, 2011. 12(1): p. 364 -369. Electric field intensity: Magnetic field distribution: Fan, J. A. , et al. Science, 2010. 328(5982): p. 1135 -1138. S. V. Boriskina, 2012 S. V. Boriskina, in Plasmonics in metal nanostructures: Theory & applications ( Shahbazyan & Stockman eds. ) Springer, 2012

Thermal SP effects cancer treatment Electric field to heat: temperature dissipation of optical energy Chen, J. , et al. Small, 2010. 6(7): p. 811 -817. nanopatterning Govorov A. O. & Richardson, Nano Today, 2007. 2(1) 30 -38 Atanasov, P. A. , et al. , Int. J. Nanopart. 2010. 3(3): p. 206 -219. S. V. Boriskina, 2012

Thermal SP effects Heat to electric field: Near-field heat transfer: (cold, T 2) d (hot, T 1) - fluctuating currents + ~ DOS + + - - + High SPP-induced DOS results in the near-field coherence e. g. , Narayanaswamy, A. & G. Chen, Appl. Phys. Lett. 2003. 82(20): p. 3544 -3546; Fu, C. J. & W. C. Tan, J. Quant. Spectr. Radiat. Transf. 2009. 110(12): p. 1027 -1036; Rousseau, E. , et al. Nat Photon, 2009. 3(9): p. 514 -517; Volokitin, A. I. & B. N. J. Persson. Rev. Mod. Phys. , 2007. 79(4): p. 1291 -1329 S. V. Boriskina, 2012

Plasmonic photosensitization of semiconductors Knight, M. W. , et al. , Science. 332(6030): p. 702 -704. • hot electrons can tunnel from metal nanoantennas into semiconductor • photon detection at energies below the semiconductor band gap Theoretical prediction: Shalaev, V. M. , et al. , Phys. Rev. B, S. V. Boriskina, 2012 1996. 53(17): p. 11388 -11402.

Plasmonic enhancement of photocurrent in graphene: in silicon: Xu, G. , et al (2012), Adv. Mater. , 24: OP 71–OP 76 Mubeen, S. , et al. , Nano Letters. 11(12): p. 5548 -5552. Echtermeyer, T. J. , et al. 2012, Nature Commun. 2: p. 458. S. V. Boriskina, 2012

Books & review articles on plasmonics: • Lal, S. Link, and N. J. Halas, Nano-optics from sensing to waveguiding. Nat Photon, 2007. 1(11): p. 641 -648 • Halas, N. J. , et al. , Plasmons in strongly coupled metallic nanostructures. Chem. Rev. , 2011. 111(6): p. 3913 -3961 • Schuller, J. A. , et al. , Plasmonics for extreme light concentration and manipulation. Nature Mater. , 2010. 9(3): p. 193 -204 • Stockman, M. I. , Nanoplasmonics: past, present, and glimpse into future. Opt. Express. 2011, 19(22): p. 22029 -22106 • Maier, SA, Plasmonics: Fundamentals and Applications, Springer, NY, 2007 • Novotny, L. , and B. Hecht. Principles of Nano-Optics, Cambridge University Press, 2006 This list is by no means complete … S. V. Boriskina, 2012

Commercial & free software • Lumerical FDTD Solutions http: //www. lumerical. com/tcad-products/fdtd/ • COMSOL Multiphysics® (FEM) http: //www. comsol. com/products/multiphysics/ • MEEP (FDTD) http: //ab-initio. mit. edu/wiki/index. php/Meep • DDSCAT (discrete dipole approximation) http: //www. astro. princeton. edu/~draine/DDSCAT. html • A collection of free software (including Mie theory methods) http: //www. scattport. org/index. php/light-scattering-software S. V. Boriskina, 2012

Topics I had to omit due to the lack of time Plasmonic cloaking: New Journal of Physics, Focus Issue on 'Cloaking and Transformation Optics', Guest Editors: Ulf Leonhardt and David R. Smith, Vol. 10, Nov 2008. Non-local response: A. D. Boardman, Electromagnetic Surface Modes, Ch. Hydrodynamic Theory of Plasmon–polaritons on Plane Surfaces, John Wiley & Sons Ltd. , 1982. Resonant energy transfer & ‘dark’ plasmonic nanocircuits: Andrew, P. and W. L. Barnes, Energy Transfer Across a Metal Film Mediated by Surface Plasmon Polaritons. Science, 2004. 306(5698): p. 1002 -1005 Akimov, A. V. , et al. , Generation of single optical plasmons in metallic nanowires coupled to quantum dots. Nature, 2007. 450(7168): p. 402 -406. Boriskina, S. V. and B. M. Reinhard, Spectrally and spatially configurable superlenses for optoplasmonic nanocircuits. Proc. Natl. Acad. Sci. USA, 2011. 108(8): p. 3147 -3151. Spasers: Stockman, M. I. , Spasers explained. Nat Photon, 2008. 2(6): p. 327 -329. Plasmonic particles on demand: Luther, J. M. , et al. , Localized surface plasmon resonances arising from free carriers in doped quantum dots. Nat Mater, 2011. 10(5): p. 361 -366. finally, Metamaterials is a huge area in itself – could be a separate class S. V. Boriskina, 2012