Enhanced Light Interaction with Organic Molecules in Photonic Crystal Slabs

Technology #15669

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FIG. 1A is a schematic diagram of a large-area, square-lattice photonic crystal 100 whose energy band structure (shown in FIG. 1B) includes a Fano resonance at or near a wave vector of k = 0 (i.e., at or near the Γ point).FIG. 1B Energy band structure.FIG. 1C Energy level diagram.FIG. 1D shows a photonic crystal 150 (left) comprising a square lattice of high-ε dielectric rods 152 (ε H = 12.25) embedded in a low-ε dielectric material (εL = 2.25).FIG. 1E shows another CCW photonic crystal 160 (left) formed by patterning holes 162 in a dielectric slab 161. Holes 164 arrayed along one column are enlarged to form a coupledcavity waveguide. The central image in FIG. 1E illustrates the guided mode, and the plot at right illustrates the CCW photonic crystal’s photonic band structure.FIG. 1F shows a coupled resonator photonic crystal 170 with holes 172 on a first square lattice of period a in a dielectric slab 171. This photonic crystal 170 also includes filled holes 174 arranged on second square lattice of period 3a that is aligned with the first square lattice. The plots at right in FIG. 1F illustrate experimental measurements of this photonic crystal’s band structure.
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Inventors
Professor Marin Soljacic
Department of Physics, MIT
External Link (www.mit.edu)
Professor John Joannopoulos
Institute for Soldier Nanotechnologies, MIT
External Link (ab-initio.mit.edu)
Ofer Shapira
Song Liang Chua
Bo Zhen
Physics, MIT
Jeongwoon Lee
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

EXCITATIExcitation enhancement and extraction enhancement with photonic crystals

US Patent 8,969,831

Applications

Several applications for this technology are found in molecular sensing and detection as well as organic light emitting devices.

Problem Addressed

Currently, the incorporation of organic molecules in optical cavities is challenging and often impossible due to the incompatible fabrication processing with the typically inorganic cavity structure.

Technology

This invention depicts a system for stimulating an emission from at least one emitter, such as a quantum dot or organic molecule, on the surface of a photonic crystal comprising a dielectric substrate. This system includes a laser or other source that illuminates the emitter and the photonic crystal, which is characterized by an energy band structure exhibiting a Fano resonance, from a first angle so as to stimulate the emission from the emitter at a second angle. The coupling between the photonic crystal and the emitter may result in spectral and angular enhancement of the emission through excitation and extraction enhancement. These enhancement mechanisms also reduce the emitter's lasing threshold.

Advantages

  • Ability to create more efficient organic light emitting devices
  • A more sensitive molecular sensing