Efficient Terahertz Sources by Optical Rectification in Photonic Crystals and Metamaterials Exploiting Tailored Transverse Dispersion Relations

Technology #12267

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FIG. 1 is a schematic diagram illustrating a THz source formed in accordance with the invention;FIG. 2A is a schematic diagram illustrating a photonic crystal having the same design as the photonic crystal described in FIG. 1; FIG. 2B is a projected band diagram of the photonic crystal shown in FIG. 2A; FIG. 2C is a contour graph of the second band.FIG. 3 is a graph illustrating a simulated radiation spectrum when an ultra-fast optical pulse travels through the photonic crystal in FIG. 1.
Professor John Joannopoulos
Department of Physics, MIT
External Link (web.mit.edu)
Professor Marin Soljacic
Department of Physics, MIT
External Link (web.mit.edu)
Professor Erich Ippen
Department of Electrical Engineering and Computer Science, MIT
External Link (web.mit.edu)
Rafif Haman
Department of Mathematics, MIT
Mihai Ibanescu
Research Laboratory of Electronics, MIT
Peter Rakich
Research Laboratory of Electronics, MIT
Even Reed
Lawrence Livermore National Laboratory
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Efficient terahertz sources by optical rectification in photonic crystals and metamaterials exploiting tailored transverse dispersion relations

US Patent 7,421,171


The technology can be used to improve the efficiency of THz generation for imaging and spectroscopic applications in the medical, security and manufacturing sectors.

Problem Addressed

A major limit in generating terahertz radiation from optical rectification in electro-optic materials comes from optical break down processes in these materials. More efficient generation can be obtained by increasing the optical power level, but this input optical power has to be below the threshold of optical breakdown of the crystal.


The invention describes the improvement of the efficiency of THz generation via optical rectification by making use of specially tailored transverse dispersion relations in photonic crystals (a good candidate is lithium niobate) and the associated enhanced density of photonic states.


  • Improves the efficiency of THz generation
  • Wide range of applications
  • Provides better resolution over longer wavelength microwave radiation