Plasmonics in random media Cid B. de Araújo

Transcription

1 Plasmonics in random media Cid B. de Araújo Departamento de Física Universidade Federal de Pernambuco Recife Brazil 1

2 Plasmonics Science and technology that deals with the generation, control, manipulation, and transmission of plasmon excitation in metal nanostructures 2

3 Surface plasmons in nanoparticles Notre Dame de Paris Cu, Ag, Au 3

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5 5 Boyd, Swieca School 2004

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7 Surface plasmon frequency (depend on shape, size and material) E in in E 0 applied electric field nanosphere in 1 2 p 2 host dielectric function Drude dielectric function SP frequency is therefore: p 1 2 (This assumes particle is small compared to wavelength.) 0 7

8 Extinction coefficient C ext 9 c 3/ 2 m V Mie theory 1908 (dipole aproximation) m 2 nanospheres Silver in aqueous colloid 8

9 Metal nanoshell colloids Plasmon resonance tunable by core and shell dimensions t = 20 nm 15 nm 10 nm 5 nm 9

10 Near-field intensity Schatz et al. Spatial extension: nm 10

11 Coupled nanoparticles Kottmannn, Martin Opt. Lett 2001 Field increases by 24 for particles with diameter of 20 nm. Intensity enhancement >

12 More complex nano-structures n=1.5 Log enhancement 40 nm 600nm Plasmonic nanolens: First proposed by Li, Stockman & Bergman, PRL (2003) Bidaut, JACS

13 Metal-dielectric nanocomposites Plasmon enhanced fluorescence Third-order nonlinear optics in plasmonic materials Random lasers Surface plasmon resonances may increase NL response Scale size of inhomogeneities << optical wavelength Optical susceptibility can be described by volume averaged quantities 13

14 Plasmon enhanced luminescence ATOM Novotny et al. PRL 2006 PL (, ) ( ) ( ex PL abs ex rad PL ) 14

15 Fractals structures and hot spots Shalaev et al. Marder et al. Optical glasses doped with trivalent rare earth ions containing silver or gold NPs 15

16 No Au NPs 16

17 Enhanced luminescence at 614 nm (excitation at 405 nm) 17

18 Absorption spectra Absorption (a.u.) Frequência (%) Frequency upconversion in Er 3+ doped PbO-GeO 2 glasses containing silver nanoparticles 59 PbO 41 GeO 2 40,0 35,0 1,0 0,8 4 G 11/2 no silver NP 16h 39h 51h 0,4 0,3 Plasmon Ag 4 F 3/2 + 4 F 5/2 2 G 9/2 4 F 7/2 2 H 11/2 30,0 25,0 20,0 15,0 10,0 5,0 0, Diâmetro da nanoparticulas (nm) 0,2 4 S 3/2 0,6 0,1 0, Wavelength (nm) 0,2 4 F 9/2 4 I 9/2 4 I 11/2 4 I 13/ Wavelength (nm) Appl. Phys. Lett. 90, (2007) 18

19 100% enhancement Infrared laser Infrared laser 980 nm 680 nm 547 nm 530 nm 980 nm Nanothermometer 19

20 Tellurium glass with silver NPs doped with Pr 3+ or (Tb 3+ - Eu 3+ ) or Tb 3+ : J. Appl. Phys. 105, (2009). J. Appl. Phys. 104, (2008). J. Appl. Phys. 103, (2008). Gemanate glass doped with Eu 3+ or (Yb 3+ -Er 3+ ) containing silver, gold or copper NPs: Appl. Phys. Lett. 94, (2009). Appl. Phys. B 94, 239 (2009). Appl. Phys. Lett. 92, (2008). 20

21 Nonlinear Optics Interaction light-matter under circunstances that the linear superposition principle is violated Optical polarization Dipole moment per unit volume P = o [ (1) E + (2) E 2 + (3) E ] (n) 0, n = even (centro-symmetric media) P induces changes in the speed of light in the medium and new frequencies may be generated 21

22 Nonlinear Optics hold great promise for applications such as: All-Optical Switching Optical Limiting Optical Sensors Lasers and Amplifiers but the lack of appropriate materials do not allow the implementation of many ideas already presented 22

23 Z-scan technique Nonlinear refraction n = n 0 + n 2 I(r) n 2 > 0 self focusing n 2 < 0 self defocusing Tn 2 I Nonlinear absorption = I(r) T 2 I n 2 > 0 n 2 < 0 23

24 Colloids containing metallic nanoparticles Local field enhancement (3) (3) NP Surface plasmon resonance 2 eff f 2 Filling fraction Re (3) host ( ) 2 ( ) 0 NP sp h sp NP 3 NP( ) ( ) 2 ( ) h 24

25 Third order susceptibility of silver colloids Sodium citrate PVP Z scan 532 nm 80 ps 5 Hz PVA Sodium citrate PVP PVA Ag Influence of stabilizing agents and dipole moment of solvents Susceptibility changes by more that 100% for PVA and PVP J.O.S.A. B 24, 2136 (2007) Applied Physics B 92, 61 (2008) 25

26 Number of particles NL susceptibility of silver nanoparticles in CS 2 Competing processes between nonlinearities of the constituents Silver NPs capped with dodecanethiol (b) 80 average diameter: 3.9 nm 50 nm Diameter of particles (nm) i i h 2 h 5 nm eff h 1 3 f 26 1 f

27 n 2 (10-14 cm 2 / W ) 4.0 (a) NL Maxwell Garnet model (3) eff (3) h f (3) ( a i b) NP (3) NP 16 ( 6.3 i 1.9) 10 m V f ( 10-5 ) (3) h i m 2 /V 2 Control of spatial and temporal profile of optical beams (Space and temporal solitons) 2 (cm/gw) (b) f ( 10-5 ) 27 J.O.S.A. B 22, 2444 (2005)

28 First observation of high-order nonlinearities in Ag aqueous colloids Normalized transmittance Normalized transmittance Z-scan nm (single pulses 5 Hz) NL refractive behavior Nonlinear absorption Z (mm) (a) (b) Z (mm) T n2i T 2 I 3rd order T I J.O.S.A. B 24, 2948 (2007) 28

29 n 2 (x10-18 m 2 / W ) n 4 (x10-30 m 4 / W 2 ) NL refraction NL absorption 3rd. order nonlinearity f ( x 10-4 ) 2 (x10-10 m / W ) f ( x 10-4 ) 5th. order nonlinearity f ( x 10-4 ) 4 (x10-23 m 3 / W 2 ) f ( x 10-4 ) High order nonlinearities also depend linearly with f [Up to (9) ] 29

30 Thermally managed eclipse Z-scan Large rep rate 70 MHz Opt. Express 15, 1712 (2007) 30

31 No crossing PbO-GeO 2 film with copper NPs Influence of the Surface Plasmon Resonance Laser pulses 150 fs Appl. Phys. Lett. 92, (2008) 31

32 Nonlinear refraction at 1560 nm Nanoshells silica-gold Absorbance (arbtrary units) Normalized Transmitance. Normalized Transmittance 2 Metal Nanoshell Thermally - managed eclipse Z-scan 1 Laser 1560 nm Inner radius: 50 nm Outer radius: 70 nm Wavelength (nm) n 2 = 20 x m 2 /W 1.06 Laser pulses 60 fs time = 20us Peak Valley Z/Z Time (us) 32

33 HYBRID COMPOSITES Silver NPs in-situ growth within crosslinked poly (ester co - styrene) induced by UV irradiation aggregation control with exposition time J. Phys. Chem. Solids 68, 729 (2007) Silver NPs (5-10 nm) 33

34 Lithography 34

35 Random lasers (lasers without mirrors) Lawandy et al. Nature 1994 Generated photons make a random pathway due to reflection by the TiO 2 particles 2 x 10-3 M particles / cm 3 Mean free path: nm and nm Intensity mj 15

36 Intensidade Normalizada Intensidade (a.u.) Rh6G Our polymers with TiO 2 particles TiO 2 particles Rhodamine 6G 2 x 10-3 M particles / cm 3 Mean free path: nm and nm 1,0 0,8 0,6 2 mw 15 mw 160 mw (2 mw) (15 mw) (150 mw) , , , (nm) Line narrowing (nm) Threshold like behavior 36

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38 Is it possible to operate a random laser with directional emission but using no mirrors? Photonic band gap fiber Refractive index profile Colloid with Rh 6G +TiO 2 Hollow core fiber Transverse feedback: total internal reflection Axial feedback: multiple scattering 38

39 First Random Fiber Laser 100 times more efficient than conventional random lasers Phys. Rev. Lett. 99, (2007) 39

40 Nd 3+ doped fluoroindate glass 575nm ( 4 I 9/2 2 G 7/2 ) 40

41 Upconversion Random Laser Fluoroindate glass powder Normalized UV signal 381 nm Above threshold 30 m 41

42 NEXT STEP Random fiber laser based on Nd 3+ doped nanocrystals + metal nanoparticles combined effects of multiple light scattering with local field enhancement due to surface plasmons reduced threshold 42

43 Plasmonics: a fundamentally multidisciplinary enterprise Fundamental science of metallic nano-optical components Plasmon-enhanced spectroscopies for chemical & biodetection SPASER nanoshells Raman Shift (cm -1 ) In vitro and in vivo Biomedical applications wavelength (nm) Light harvesting for energy conversion Optical interconnects in nextgeneration computer chips Plasmonic solar cells 43

44 Web of Science 01/Sept/2009 Keywords: plasmonics; surface plasmons; surface plasmon polaritons; localized surface plasmons. 44

45 Web of Science 01/Sept/2009 Keywords: plasmonics; surface plasmons; surface plasmon polaritons; localized surface plasmons. 45

46 Ernesto Valdez Rodriguez (D. Sc. 2007) Research Associate Antonio Marcos Brito-Silva D. Sc. student - Materials Science Denise Valença M. Sc. student Physics Euclides C. Lins de Almeida - D. Sc. student - Physics Gemima Barros Correia D. Sc. student Materials Science Hans A. Garcia Mejia - D. Sc. student - Physics Marcos André Soares de Oliveira D. Sc. student Physics Milena Frej M. Sc. Physics Ronaldo P. de Melo D. Sc. student Materials Science Tâmara P. R. de Oliveira - D. Sc. student - Physics Jamil Saade D. Sc. Student Materials Science Renato B. Silva M. Sc. Student Materials Science A. Galembeck - UFPE L. Kassab FATEC SP M. Poulain Rennes France Y. Messaddeq UNESP - SP 46

47 Surface plasmons: electromagnetic resonances in the visible Localized plasmon oscillation Propagating surface plasmon polariton (SPP) dielectric metal 4 3 m 0R 2m k x m d c m d 1/ 2 dielectric metal 47

48 Pr 3+ in Ga 10 Ge 25 S 65 with Ag nanoparticles Heat treatment: 23 h JAP 103, (2008) 48

49 Heat treatment 23 hours ( P0 H4) ( D2 H4) Increase by 130 % 49