Design of Magnetoplasmonic Resonant Nanoantennas for Biosensing Applications

Transcription

1 Presented at the COMSOL Conference 2010 Paris Design of Magnetoplasmonic Resonant Nanoantennas for Biosensing Applications M. ESSONE MEZEME a and C. BROSSEAU b Lab-STICC, Université de Bretagne Occidentale CS 93837, 6 avenue Le Gorgeu, Brest Cedex 3, France a melvin.essone@univ-brest.fr b brosseau@univ-brest.fr COMSOL CONFERENCE 2010, NOVEMBER , PARIS, FRANCE

2 Brosseau s group activities - Electromagnetic wave transport in composite materials Introduction (1) concrete Colloidal suspension 2 - Multiscale modeling of biological cells - Interface Physics-Biology (interaction electromagnetic wave - human body)

3 3 Earlier work [1-2] Cell Introduction (2) Cell division Membrane disruption [1] P. Salou, A. Mejdoubi, and C. Brosseau, J.Appl. Phys.105, (2009) [2] M. Essone Mezeme and C. Brosseau, J.Appl. Phys.107, (2010), ibidem 108, (2010)

4 4 Introduction (3) Design of new magneto-plasmonic core-shell nano-antennas Fe 3 O 4 Au: ideal metal Fe 3 O 4 : ferromagnetic oxide Au and Fe 3 O 4 : biocompatible materials Au Principles: -Plasmonic resonance: surface plasmon excitation and energy confinement in very small length scale -Gyromagnetic resonance: magnetic localization and microwave heating Advantages: -Controllable by H -Separation of length scales (cell size 10µm and nanoantenna length 100nm) -Confinement of electric field enhancement( 40nm)

5 5 Outline 1- Numerical model and simulation 2- Results and discussion 3- Concluding remarks

6 6 Numerical model and simulation (1) - 3 phase system -Core-shell structure embedded in a biological material -Cross-section of infinitely extended structure in the z direction ( 2D) -Finite structure (3D) y E µ 1, ε 1 µ 2, ε 2 Γ 1 Γ2 Γ4 R µ 3, ε 3 e L Au z x H Γ 3 Isotropic shape p Anisotropic shapes r Fe 3 O 4 R 50nm, e 5nm, p 50nm and r 10nm Boundary conditions: Γ 1 : V 2 = 1V Γ 2 : V/ n= 0 Γ 3 : V 1 = 0V Γ 4 : V/ n= 0 Γ 1 : J 2 = 1Am -2 Γ 2 : H n= 0 Γ 3 : J 1 = -1Am -2 Γ 4 : H n= 0

7 7 heterogeneous homogeneous µ i, ε i µ, ε ε 1 : water ε 2 and ε 3 : Drude model µ 1 = µ 2 =1 Numerical model and simulation (2) µ 3 : Landau-Lifshitz-Gilbert relaxation model Assumptions: -Long-wavelength physics λ >> system size no scattering. -Dielectric properties of biological material assimilated to water -Continuum medium approach Water: Phase1 Au: Phase2 Fe 3 O 4 : Phase3 µ 1, ε 1 V 2 L Effective permittivity: 1 V k ( x, y) ε = ( V V )² ε S 2 1 x 2 + V y 2 Effective permeability: 1 µ = k x y H x y dxdy H L µ (, ) ²(, ) ( )² S app dxdy µ, ε 2 2 µ 3, ε 3 H app V 1

8 8 Results and discussion (1) 1.04 (a) (a) (b) 1.00 µ' 0.96 R e=30 nm µ" a b c d GYR (b) (c) (d) F (GHz) GYR: Gyromagnetic resonance Magnetic Field Enhancement (MFE) MFE= H / H app

9 9 Results and discussion (2) Electric Field Enhancement (EFE) EFE= E / E app a b d Influence of shape 15 d E y d 1 d 1 d 3 ε" ε' d 2 d 3 d 4 d 2 d F (THz)

10 10 Parameters 2-dimensional 3-dimensional Results and discussion (3) H F GYR 4.5 GHz 4.5 GHz F PLR 250 THz 100THz MFE EFE Confinement length 20nm 40nm Au concentration 3.5% 0.6% Fe 3 O 4 concentration 7.0% 1.4% EFE at PLR MFE at GYR d 2

11 11 Concluding remarks (1) Magneto-plasmonic core-shell nano-antennas are based on: Magnetic core: -Controllable by H -Useful for local microwave heating (hyperthermia) Plasmonic shell: -Induces a localized enhancement of E on 40nm -Optically detectable Perspectives Membrane disruption Curvature fluctuation Surface charges Mechanical stress

12 12 Concluding remarks (2) Possible experimental realization of optical antennas using stuffed carbon nanotube : K. Kempa et al. Adv. Mater. 19, (2007) Acknowledgement: The Conseil Régional de Bretagne is thanked for the funding of this project