NIRT: Photon and Plasmon Engineering in Active Optical Devices Based on Synthesized Nanostructures

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NIRT Photon and Plasmon Engineering in Active
Optical Devices Based on Synthesized
Nanostructures Marko Loncar1, Mikhail Lukin2 and
Hongkun Park3 1Harvard Electrical Engineering,
2Harvard Physics, 3Harvard Chemistry

• Program Goals
• Understanding and engineering of fundamental
  properties of light generation and control in
  active optical nanostructures
• Development of robust and practical devices and
  systems for optical and quantum optical
  communication and information processing (e.g.
  single photon sources, low-power/single-photon
  switches, nano-lasers).
• Answer important questions that pertain to
  hybrid nanostructures integration of different
  fabrication techniques, integration across
  different length-scales, efficient information
  exchange between nano-structures and macro-world,
  light-matter interaction on a nanoscale.

• Approach
• Combination of bottom-up synthesized nanoscale
  light emitters and metallic (Ag, Au) nanowires
  with top-down nanofabricated advanced structures
  for light localization, such as nano-scale
  surface plasmons and photonic crystals.
• Bottom-up synthesized nanocrystal quantum dots
  (QDs) offer number of advantages over
  conventional epitaxially grown QDs, including
  better uniformity, ease of fabrication and
  integration with passive optical platforms, and
  multi-wavelength operation.
• Synthesized metallic nanowires can be
  crystalline, and are superior to top-down
  fabricated metallic waveguides (lower loss)
• Photonic crystal cavities can enhance radiation
  from QDs due to large Purcell factor enabled by
  their large quality factor and small mode volume.

Hybrid Nanophotonic-Plasmonic Platform for
Efficient Generation and Extraction of Photons
Waveguide couplers

• Broader Impact
• Powerful and unique educational opportunities
  for students
• interdisciplinary nature of our NIRT exposes
  students to theoretical work, nanostructure
  synthesis, device physics and engineering,
  nanofabrication and optical characterization.
• team members co-advise students and hold
  bi-weekly joint group meetings
• undergraduate students and minorities
  participate in the efforts of our NIRT through
  the NSF supported Research Experience for
  Undergraduates program.
• The team members give public lectures and
  organize science projects at local public
  schools, mentor high school students and work
  with high school teachers (NSF RET)
• The team members participate in ongoing Harvard
  outreach programs, as well as engage the
  business-oriented public (e.g. Harvard
  Nanotechnology Business Forum, Harvard
  Industrial Outreach Program).
• The knowledge and techniques developed in this
  program will find application in other fields,
  including life sciences (e.g. surface-plasmon
  enhanced sensing techniques), advanced
  photolithography, particle manipulation
  (tweezing), etc.

Future Directions
Single-photon transistor. In the storage step, a
gate pulse consisting of zero or one photon is
split equally in counter-propagating directions
and coherently stored using an impedance-matched
control field (t ). The storage results in a spin
flip conditioned on the photon number. A
subsequent incident signal field is either
transmitted or reflected depending on the photon
number of the gate pulse, owing to the
sensitivity of the propagation to the internal
state of the emitter.D. E. Chang et al., Nature
Physics, 3, 807 (2007)
Strong-coupling in SiNx nanocavities embedded
with diamond nanocrystals We designed a photonic
crystal nanocavity with a quality factor Qgt106, a
mode volume of Vmod0.78(?/n)3, and an operating
wavelength of ?637 nm in SiNx (n2). Strong
coupling between a nanocrystal with an embedded
nitrogen-vacancy color-center and the cavity mode
is achievable for a range of cavity
dimensions. M. W. McCutcheon M. Loncar, Optics
Express (in press)
Ultra-high Q cavities based on semiconductor
nanowires By defining one-dimensional photonic
crystal at nanowire ends cavities with Q106 and
Vmode lt0.2(?/n)3 have been designed. Our
cavities are well-suited for the realization of
nanowire-based low-threshold lasers,
single-photon sources and quantum optical devices
that operate in the strong-coupling limit. Y.
Zhang M. Loncar, Optics Express, 16, 17401
(2008)