Nanophotonics

The objective of our research is to control optical energy and its conversion on the nanometer scale by combining the properties of metal, organic, semiconductor, and dielectric materials to create new, combined states of light and matter. Specific examples of our targets are:

• Controlled quantum coupling at the nanoscale: The ability to prepare coupled nanostructures presents the opportunity to induce and control the interactions of photons, plasmons, and excitons, thereby producing new elementary excitations. Basic science research on these excitations is performed, with application to many disciplines such as solar energy conversion, nanoscale photonic devices, new photochemical processes, and quantum logic.
• Understanding ultrafast processes at ultrasmall length scales: The outcome of ultrafast processes can be very different in nanoscale vs. bulk materials, with potentially great impact on the physical properties and photochemical products of the nanoscale system. Research is performed to understand, optimize, and control these differences.
• New routes to functional nanophotonic materials: The group is pursuing the development of new optical materials via three directions:
  • Advanced colloidal synthesis,
  • Lithographically assisted synthesis, and
  • New near-field optical lithography methods to generate hybrid nanoscale structures over large areas.
• Efficient energy transport in plasmonic nanostructures: We are performing research to significantly improve
  • The range of plasmon propagation,
  • The spectral bandwidth that can be supported by plasmonic structures, and
  • The minimum lateral dimension of efficient plasmon propagation. The work will be the basis for wholly new, efficient solar concentrators or all optical nanoscale circuitry.

To achieve these objectives, we are using a three-pronged approach

1. Materials generation via synthesis and lithography,
2. Optical instrumentation development for advanced characterization, and
3. Rigorous numerical simulations.

Available Equipment

• Near-field scanning optical microscope (NSOM): A versatile instrument that is capable of apertureless and aperture NSOM, equipped with lasers that enable laser excitation from 260 nm to 2.4 microns. Many variable illumination and detection geometries are available to accommodate a range of samples properties and near-field contrast mechanisms.
• Confocal Raman microscope: A range of illumination wavelengths (514, 632, ultraviolet) and objectives are available to enable micro-Raman spectroscopy.
• Ultrafast transient absorption spectroscopy (coming soon): This instrument is equipped with a 35-fs oscillator, amplified at 5 kHz. An OPA capable of operation from 240 nm to 11 microns is available. Transient absorption spectrometer enables simultaneous three-dimensional data collection (spectra/kinetics) for probe wavelengths of 450 to 1600 nm.
• Ultrafast for ultrasmall facility (coming soon): This instrument contains a 35-fs oscillator and inverted microscope. Advanced pulse shaping and pulse compression enables a pulse of approximately 12 fs at the sample, despite traveling through a microscope objective. Transient pump-probe and time correlated single photon counting is available.
• Size-selected cluster facility and cluster-based nanomaterials for nanophotonics and nano(photo)catalysis
  • Controlled deposition of size- and composition-selected metal clusters with masses up to 2000 amu for the fabrication of highly monodisperse materials at the sub-nanometer scale
  • Clusters as uniform building blocks for the synthesis of larger nanostructures.