NIRT: Opto-Plasmonic Nanoscope

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NIRT Opto-Plasmonic Nanoscope
NSF NIRT Grant ECS-068863 PIs Y. Fainman, V.
Lomakin, A. Groisman, and G. W.
Schmid-Schoenbeim University of California, San
Diego, La Jolla, California 92093-0407 Tel (858)
534-8909 Fax [phone] E-mail
fainman_at_ece.ucsd.edu web site
http//emerald.ucsd.edu
Objective Plasmonic microscopy with
sub-wavelength resolution
Nanoscope in Plasmonic Era
SPP Heterodyne Imaging Setup
Diffractive plasmonics SPP Fresnel Zone Plate
Fresnel diffraction of SPP
FEM Simulation Transmission through Si
bumps
Microscope Diffraction limited
Plasmonic nanoscope Sub-diffraction limited
SPP Fresnel Zone Plate
Fresnel Zone Plate
Power Transmission 0.3
Sample illumination
CCD Output
Fresnel diffraction
Input and reference pulse l0 1.55 mm FWHM
200 fs
A SPP Fresnel zone plate was fabricated at
aluminum (Al)/air interface and worked at the
free space wavelength of 1.55 µm (?spp 1.547
µm). The designed focal length was 80 µm.
R. Rokitski, KA. Tetz, Y. Fainman, PRL, vol.95,
no.17, 21 Oct. 2005, pp.177401/1-4
A 1879 optical microscope
Our focusing approach
Sub-diffraction limited focusing
Time averaged SPP mode
Time-resolved SPP interferogram
R. Rokitski et al, Phys. Rev. Lett. 95, 177401
(2005)
L. Yin et al, Nano Lett. 5, 1399 (2005)
SPP Bloch modes in 2-D nanohole array
Time evolution of SPP wavepacket
Calculated vs Measured Field
Sample preparation and fabrication
l 1.5 mm, NIR
Spatial amplitude and phaseof scattered SPP field
Field intensity distribution at the focal plane
Measurement
Fresnel Diffraction Calculation
t 0 fs
t 133 fs
t 266 fs
t 400 fs
Normalized frequency (wa/2pc a/l)
Phase matching condition (resonant Woods
anomaly)
Si-on-Al SPP Fresnel Zone Plate
Assuming small modulation (d ltlt a), and no
coupling between adjacent sides
Diffraction theory is valid for SPP
Ultrafast SPP electrodynamics
20 µm
5 µm
(planar case)
(?-X)
Time-resolved SPP focusing
Sample fabrication nanoholes in metal films
Spatial phase focused SPP fields
SPP plane wave excitation
Snapshots of amplitude at different time
Spatial amplitude and phase with converging and
diverging illumination

• Variety of substrates (GaAs, Si, SiO2, Al2O3)
• Evaporation or sputtering of Al, Au, or Ag
  metallic films (thickness h 50-200 nm)
• ICP-RIE and wet etching (hole diameters d
  100-500 nm)

How to make sure the incident SPP wave is planar?
Image without Fresnel zone plate
Excitation Array
Detection Array
Image with Fresnel zone plate
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 NSFs
  REU program
• Establishing education and outreach projects with
  the UCSDs 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
• http//emerald.ucsd.edu

L. Feng, K. Tetz, B. Slutsky, V. Lomakin, Y.
Fainman, Appl. Phys. Lett. 91, 081101 (2007)
Imaging various SPP modes
R. Rokitski, KA. Tetz, Y. Fainman, Phys. Rev.
Lett., vol.95, 2005, pp.177401/1-4
Diffractive SPP focusing
Radiative vs. material damping
a/l0
SPP focusing after the compensation of
radiation loss
SPP focusing
ASE ? 1520-1570 nm

• Simultaneous measurement of both planar and
  corrugated surface propagation lengths
• Determines radiative decay (coupling strength)
  from grating array

Measured focal length 83µm Designed focal
length 80µm
High intensity focused SPP field is observed
L. Feng, K. Tetz, B. Slutsky, V. Lomakin, Y.
Fainman, Appl. Phys. Lett. 91, 081101 (2007)
Fainman Y, Tetz K, Rokitski R, Pang, Optics
Photonics News, vol.17, 24-9, 2006