NIRT: Opto-Plasmonic Nanoscope NSF NIRT Grant ECS PIs: Y. Fainman, V. Lomakin, A. Groisman, and G. W. Schmid-Schoenbeim University of California, San Diego, La Jolla, California Tel: (858) ; Fax: (858) ; web site: Microscope: Diffraction limited Nanoscope in Plasmonic Era Plasmonic nanoscope: Sub-diffraction limited A 1879 optical microscope Our focusing approach Sub-diffraction limited focusing R. Rokitski et al, Phys. Rev. Lett. 95, (2005)L. Yin et al, Nano Lett. 5, 1399 (2005) Objective: Plasmonic microscopy with sub-wavelength resolution Assuming small modulation (d << a), and no coupling between adjacent sides: Phase matching condition (resonant Wood’s anomaly): (planar case) (  -X) Normalized frequency (  a/2  c = a/ ) ~ 1.5  m, NIR SPP Bloch modes in 2-D nanohole array Sample fabrication: nanoholes in metal films Variety of substrates (GaAs, Si, SiO 2, Al 2 O 3 ) Evaporation or sputtering of Al, Au, or Ag metallic films (thickness h ~ nm) ICP-RIE and wet etching (hole diameters d ~ nm) 200  m Al on GaAs 1  m E-beam direct write Tailored structures on same substrate for comparison Limited area (~ 200  m) E-beam direct write Tailored structures on same substrate for comparison Limited area (~ 200  m) 200  m Au on SiO 2 1  m Holographic lithography Use of chemically amplified negative resist (SU-8) Precise control of fill factor (easier to make small holes) Large areas (~ 1 cm 2 ) Holographic lithography Use of chemically amplified negative resist (SU-8) Precise control of fill factor (easier to make small holes) Large areas (~ 1 cm 2 ) SPP Heterodyne Imaging Setup Time averaged SPP mode* Time-resolved SPP interferogram Input and reference pulse: 0 = 1.55  m FWHM ~ 200 fs CCD Output Sample illumination R. Rokitski, KA. Tetz, Y. Fainman, PRL, vol.95, no.17, 21 Oct. 2005, pp /1-4 Time evolution of SPP wavepacket Spatial amplitude and phaseof scattered SPP field  = 0 fs  = 133 fs  = 266 fs  = 400 fs Ultrafast SPP electrodynamics Spatial phase: focused SPP fields Spatial amplitude and phase with converging and diverging illumination R. Rokitski, KA. Tetz, Y. Fainman, Phys. Rev. Lett., vol.95, 2005, pp /1-4 Radiative vs. material damping Simultaneous measurement of both planar and corrugated surface propagation lengths Determines radiative decay (coupling strength) from grating array Diffractive plasmonics: SPP Fresnel Zone Plate SPP Fresnel Zone Plate A SPP Fresnel zone plate was fabricated at aluminum (Al)/air interface and worked at the free space wavelength of 1.55 μ m (λ spp = μm). The designed focal length was 80 μ m. Fresnel Zone Plate Al Si Sample preparation and fabrication Si-on-Al SPP Fresnel Zone Plate Si-on-Al SPP Fresnel Zone Plate 20 μm5 μm SPP plane wave excitation Excitation Array Detection Array How to make sure the incident SPP wave is planar? Image with Fresnel zone plate Image without Fresnel zone plate Diffractive SPP focusing High intensity focused SPP field is observed SPP focusing SPP focusing after the compensation of radiation loss Measured focal length: 83μm Designed focal length: 80μm Fresnel diffraction of SPP Fresnel diffraction FEM Simulation: Transmission through Si bumps Power Transmission ~ 0.3 Calculated vs Measured Field Diffraction theory is valid for SPP Fresnel Diffraction Calculation Measurement Field intensity distribution at the focal plane Time-resolved SPP focusing Snapshots of amplitude at different time Education, Outreach, and Data Dissemination Established new graduate courses: Nanophotonics (ECE 242A) and Optics in Space and Time (ECE 240B) Modified Undergraduate Photonics Laboratory in Engineering, Physics and Biochemnistry (opt. comm., CGH, and NLO) Graduate students weekly meetings and seminars on recent progress and other relevant topics in nanophotonics Involvement of undergraduate students via NSF’s REU program Establishing education and outreach projects with the UCSD’s Preuss School, designed for 6-12 grades student coming from disadvantaged households [e. g., Ph.D. students are serving as mentors and leaders of robotics club; RET program with the Undergraduate Photonics Laboratory in Engineering] Saperstein-2005 JSOE Woolley Fellow, 2006 Summer Graduate Teaching Fellow Numerous journal publications, conference presentations including invited conference papers L. Feng, K. Tetz, B. Slutsky, V. Lomakin, Y. Fainman, Appl. Phys. Lett. 91, (2007) Imaging various SPP modes a/ l 0 polarizers // to (  2,  1) type modes ASE: = nm ( G -X) noise limited spectral measurements 2.00 Fainman Y, Tetz K, Rokitski R, Pang, Optics & Photonics News, vol.17, 24-9, 2006