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

2. S.V. Boriskina, 2012 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

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

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

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

6. S.V. Boriskina, 2012 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

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

8. S.V. Boriskina, 2012 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.

9. S.V. Boriskina, 2012 Towards single-molecule sensitivity Hybrid modes in optoplasmonic molecules: 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.

10. S.V. Boriskina, 2012 Rayleigh ground excited virtual ( induced dipole) hν0hν0 Raman spectroscopy Rayleigh scattering Raman scattering hν0hν0 hν0hν0 h(ν 0 ± ν m ) hν0hν0 ν m - molecular fingerprint Stokes Raman vibrat. hνmhνm Raman – Nobel Prize in 1930 Dipole moment induced by light: polarizability tensor vibrational coordinate Rayleigh Raman (Stokes & anti-Stokes) particle size a very weak effect!

11. S.V. Boriskina, 2012 Surface enhanced Raman spectroscopy (SERS) Fleischman M,et al Chem. Phys. Lett. 1974; 26: 123. 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 E-field enhancement @ ν 0 E-field enhancement @ (ν 0 –ν m ) High field localization enables SERS fingerprinting of single molecules Nie, S. & S.R. Emory, Science, 1997. 275(5303): 1102-1106. R6G molecules on Ag nanoparticles @ the molecule position!

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

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

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

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

16. S.V. Boriskina, 2012 optical absorption H. Atwater & A. Polman, Nature Mater. 2010 Plasmonic solar cells charge carrier diffusion c-Si: 250 - 700 μm a-Si: 0.1 – 0.3 μm Electronic/photonic lengths mismatch

17. 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 Atwater & Polman, Nature Mater. 2010 scattering field enhancement waveguiding

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

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

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

21. S.V. Boriskina, 2012 ‘… the title is straight out of Enterprise's engineering room’ NextBigFuture.com SciTech forum Reconfigurable vortex transmissions: vortex nanogates Physical picture behind vortex nanogate

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

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

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

25. S.V. Boriskina, 2012 Energy flows in plasmonic nanostructures Surface plasmon polariton wave: 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

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

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

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

29. S.V. Boriskina, 2012 Thermal SP effects Heat to electric field: fluctuating currents ~ DOS Near-field heat transfer: 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 (cold, T 2 ) (hot, T 1 ) + - + - + - + - High SPP-induced DOS results in the near-field coherence d

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

31. S.V. Boriskina, 2012 Plasmonic enhancement of photocurrent Mubeen, S., et al., Nano Letters. 11(12): p. 5548-5552. Xu, G., et al (2012), Adv. Mater., 24: OP71–OP76 Echtermeyer, T.J., et al. 2012, Nature Commun. 2: p. 458. in silicon: in graphene:

32. S.V. Boriskina, 2012 Books & review articles on plasmonics: Lal, S., 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 …

33. 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

34. 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