Future electronics: Photonics and plasmonics at the nanoscale Robert Magnusson Texas Instruments Distinguished University Chair in Nanoelectronics Professor of Electrical Engineering Department of Electrical Engineering University of Texas-Arlington Arlington, Texas 76019 [email protected] http://leakymoderesonance.com/ Applied Power Electronics Conference Fort Worth, Texas March 16 – 20, 2014 1 Scope Plasmonics: Surface plasmons are coherent electron oscillations at the interface between two materials where the real part of the dielectric function changes sign across the interface. Nanoplasmonics: Plasmonics in nanoscale systems. Photonics: Technology concerned with the properties and transmission of photons, for example in fiber optics, waveguides, and lasers. Nanophotonics the study of the behavior of light on a nanometer scale. Engineering the interaction of light with particles or substances at deeply subwavelength scales. Silicon photonics: CMOS! Focus: Nanophotonic and nanoplasmonic periodic devices. 2 Nanoplasmonics Surface plasmons on dielectric-metal boundaries 3 Metal coupler example Jesse Lu, Csaba Petre, Eli Yablonovitch, and Josh Conway, “Numerical optimization of a grating coupler for the efficient excitation of surface plasmons at an Ag–SiO2 interface,” J. Opt. Soc. Am. B/Vol. 24, No. 9/September 2007 4 Undergrad plasmonics: SPR sensor experiment 5 SP-highlights Surface plasmon: EM field charge-density oscillation at the interface between a conductor and a dielectric SP: AC current at optical frequency Metallic structures: Concentrate/focus/guide light via SPs SP localization: Better than with dielectric optical means Efficient coupling/manipulation: Under intensive research Plasmonics: An electronics/photonics interface Our interest: – Interaction/generation of plasmonic states employing leaky-mode resonance effects – Fundamental plasmonic research in periodic nanostructures – Theory and experiment in all cases 6 Surface plasmons-key properties Collective excitation of the free electrons in a metal Can be excited by light: photon-electron coupling (polariton)=SPP Thin metal films or metal nanoparticles Bound to the interface (exponentially decaying along the normal) Longitudinal surface wave in metal films Can be highly confined in nanostructures (localized plasmon) Propagates along the interface: few µm to several mm (long range plasmon) Note: SP is a TM wave! 7 Model Device: Canonical periodic element Tranmission and modal properties air ε metal air Device possesses mixed cavity- Einc modal (CM) and surface- plasmon states (SPP) => Hinc EOT=extraordinary transmission FΛ Λ d Fixed Parameters εmetal = -5, F = 0.05 Yiwu Ding, Jaewoong Yoon, Muhammad H. Javed, Seok Ho Song, and Robert Magnusson, “Mapping surface-plasmon polaritons and cavity modes in extraordinary optical transmission,” IEEE Photonics Journal, vol. 3, no. 3, pp. 364–374, June 2011. 8 Parametric Map of transmission function EOT mixed SPP/CM region 1.0 d/Λ=0.086 0.2 0.37 0.46 0.72 pure SPP region 0.8 0.6 TM TM3 TM λ 2 4 / TM1 TM5 Λ TM6 0.4 TM0 TM7 0.2 cavity mode even mode (CM) region odd mode higher order SPP 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 λ d/ 9 Mixed SPP-CM Region magnetic field patterns on TM2 curve • Gradual increase of surface field enhancement associated with SPP excitation 1.0 • Abrupt change in Fabry-Perot condition 0.9 • Missing resonance peaks 0.8 λ / Λ 0.7 0.6 0.5 0.2 0.3 0.4 0.5 0.6 0.7 0.8 d/λ 10 Leaky modes and plasmons: Hybrid resonance elements 1.0 (a) (b) TM air I R 0.8 dielectric 0 (n = 1.6) 0.6 0 FΛ R Λ 0.4 F=0.4 (fixed) d=0 d 0.2 d=100nm Au d=900nm 0.0 0.5 0.6 0.7 0.8 0.9 1.0 wavelength (µm) (c) 20 (d) 15 15 10 10 5 5 λ λ d = 100 nm, = 710.5 nm 0 d = 900 nm, = 618.5 nm 0 Robert Magnusson, Halldor Svavarsson, Jae Woong Yoon, Mehrdad Shokooh-Saremi, and Seok-Ho Song, “Experimental observation of leaky modes and plasmons in a hybrid resonance element,” Applied Physics Letters, vol. 100, no. 9, pp. 091106-1–091106-3, February 29, 2012. 11 Measured spectra-computed fields PR 20 Au (a) SPP silicon 500 nm air PR 10 calculated 1.0 TM Au Si 0 0.8 measured (b) 16 0.6 TM1 0.4 8 0.2 TM1 SPP (669 nm) (799 nm) 0 0.0 R calculated 0 1.0 TE measured 10 0.8 (c) TE0 0.6 TE0 (725 nm) 0.4 5 0.2 0.0 0 0.60 0.65 0.70 0.75 0.80 0.85 0.90 wavelength (µm) Parameters: Λ = 653 nm, dPR = 560 nm, Appl. Phys. Lett. 2012 dAu = 80 nm, n = 1.6, and F = 0.35. 12 Silicon photonics: Intel vision 13 Motivation for silicon photonics Limits of microelectronics evolution Optical communication evolution Interconnection bottlenecks Compact, low loss, EMI properties SiPhot=new technology platform Low cost High performance 14 Reference: Silicon Photonics–PhD course prepared within FP7-224312 Helios project 15 Huge opportunities for innovation! Reference: Silicon Photonics–PhD course prepared within FP7-224312 Helios project 16 Basic resonance interactions Excitation of a leaky eigenmode in 1D periodic layers Higher-order diffraction regime Zero-order diffraction regime Properties of 2D nanopatterns similar in principle 17 Experimental spectra 1.0 1.0 Theory 0.8 Experiment 0.8 0.6 0.6 TE TM 0.4 0.4 Transmittance Reflectance 0.2 0.2 0.0 0.0 1460 1480 1500 1520 1540 1560 1580 1450 1500 1550 1600 1650 1700 1750 Wavelength (nm) Wavelength (nm) 1 1 Simulation 0.9 Experiment 0.8 0.8 0.7 0.6 0.6 0.4 Transmittance 0.5 Transmittance 0.4 Simulated 0.2 0.3 Measured 1.4 1.45 1.5 1.55 1.6 1.65 0 λ (µm) 0.78 0.79 0.8 0.81 0.82 0.83 0.84 0.85 0.86 Wavelength(µm) 18 Guided-mode resonance nanophotonics: Innovation/applications platform • Interesting physics/properties • Complex, interacting resonant leaky modes • 1D or 2D periodic layers • Applicable to dielectrics, semiconductors, metals Known knowns • Applicable to photonic, THz, microwave spectral regions • Remaining challenges in analysis • Remaining challenges in fabrication • Many potential application fields Unknown unknowns • Applications emerging ~Biosensors • Favorable area for R&D&A R. Magnusson et al., “Extraordinary capabilities of optical devices incorporating guided-mode resonance gratings,” Optoelectronic Devices and Materials (OPTO), Photonic Integration: Integrated Optics: Devices, Materials, and Technologies XVIII, SPIE Photonics West 2014, San Francisco, California, February 1–6, 2014. 19 Guided-mode resonance technology: Application summary Frequency selective elements - Narrowband bandstop/bandpass filters (∆λ~sub nm) - Wavelength division multiplexing (WDM) - Ultra high-Q thin-film resonators - Laser resonator frequency selective mirrors Biochemical sensors - Spectroscopic biosensors - Chemical and environmental sensors - Multiparametric biosensors (biolayer thickness, refractive index, and background in a single measurement) Wideband lossless mirrors - Wideband bandstop/bandpass filters (∆λ~100’s nm) - Mirrors for vertical-cavity lasers - Omnidirectional reflectors Polarization control elements - Polarization independent reflection/transmission elements for both 1D and 2D periodicity - Narrow or wideband polarizers - Non-Brewster polarizing laser mirrors - Polarization control including wave plates 20 Guided-mode resonance technology: Application summary Tunable elements - Tunable filters, EO modulators, and switches - Liquid-crystal integrated tunable devices - Laser cavity tuning elements - MEMS-tunable display pixels and filters - Thermally tuned silicon filters Security devices - Resonant Raman templates - Compact non-dispersive spectroscopy Thin-film light absorbers - Absorbance-enhanced solar cells - Omnidirectional, wideband, polarization-independent absorbers - GMR coherent perfect absorbers Photonic metasurfaces - Wavefront-shaping elements including focusing reflectors Dispersive elements - Slow-light/dispersion elements Hybrid resonant elements - Leaky-mode nanoplasmonics - Hybrid plasmonic/modal resonance sensors - Rayleigh reflectors with sharp angular cutoff - Rayleigh-anomaly based GMR transmission filters 21 Wideband resonant reflectors 1.0 R 0 air R0 0.8 Λ FΛ 0.6 BW~900 nm dg dh 0.4 z Ge y zero-order efficiency 0.2 T x SiO2 0 T0 0.0 2.0 2.2 2.4 2.6 2.8 3.0 3.2 wavelength (µm) Model and reflectance/transmittance spectra of a GMR mirror applying a partially etched Ge layer. Input light is in a TM polarization state. R. Magnusson et al., “Extraordinary capabilities of optical devices incorporating guided-mode resonance gratings,” Optoelectronic Devices and Materials (OPTO), Photonic Integration: Integrated Optics: Devices, Materials, and Technologies XVIII, SPIE Photonics West 2014, San Francisco, California, February 1–6, 2014. 22 Color filter array: Design Designed and optimized with RCWA Parameters: n = 2.02, F = 0.5, dg = 55 nm, and dh = 110 nm. Period-tuned resonance wavelengths enabling RGB color filters. Mohammad J. Uddin and Robert Magnusson, “Highly efficient color filter array using resonant Si3N4 gratings,” Optics Express, vol. 21, no. 10, pp. 12495–12506, May 20, 2013. 23 Results: Spectral measurements Device Parameters: dg = ≈ 60 nm, dh ≈ 105 nm, F = 0.46. High experimental efficiency (> 95%) with low crosstalk Mohammad J. Uddin and Robert Magnusson, “Highly efficient color filter array using resonant Si3N4 gratings,” Optics Express, vol. 21, no. 10, pp. 12495–12506, May 20, 2013. 24 Label-free Microarrays Based on Guided-mode Resonance Technology Products Features Fully automated benchtop reader Optical resonance with real-time data 96-well and 384-well disposable Cell-based and biochemical assays label-free microarray plates Pre-sensitized kits: standard and Dual-resonance detection enables two data custom points for every measurement Comprehensive assay support for Multiplexing capability transition to label-free ResonantSensors.com 817-735-0634 [email protected] Conclusions • Nanoplasmonics – Light on metals-compact devices – Loss/gain compromise – Rapid R&D • Silicon photonics – CMOS infrastructure – Integrated electronics/photonics chips – Commercial now – Under intense development • Nanophotonics – Device development opportunities – Opportunities in entrepreneurship/innovation [email protected] 26 .