Nanoparticles and Nanostructures for use as Optical Limiters

Technology #13760

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FIG. 1 shows transmission electron micrographs of two gold nanourchin samples analyzed in an experiment carried out in accordance with an embodiment of the invention;FIG. 2 shows normalized absorbance spectra, on a linear scale, of two nanourchin solutions, along with spectra of gold nanospheres and silver nanospheres, in samples analyzed in an experiment carried out in accordance with an embodiment of the invention;FIG. 3 is an experimental schematic of a Z-scan optical limiting setup used in experiments conducted in accordance with an embodiment of the invention;FIG. 4 shows representative Z-scans of a gold nanourchin solution and a silver sphere solution, from an experiment carried out in accordance with an embodiment of the invention;
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Inventors
Mordechai Rothschild
Lincoln Laboratory, MIT
Vladimir Liberman
Lincoln Laboratory, MIT
Managed By
Dave Sossen
MIT Technology Licensing Officer
Patent Protection

Optical limiting using plasmonically enhancing nanoparticles

US Patent 8,345,364
Publications
Nonlinear bleaching, absorption, and scattering of 532-nm-irradiated plasmonic nanoparticles
Journal of Applied Physics, 2013
Optical limiting with complex plasmonic nanoparticles
Journal of Optics, 28 May 2010

An optical limiter which uses plasmonically enhancing nanoparticles.

Applications

This invention is related to optical limiters that could be used to protect photosensitive objects (which could be human eyes as well as sensitive optical equipment) from intense light generated by lasers.

Problem Addressed

There is a need to protect photosensitive objects from laser exposure. Current ways of addressing this includes using dark sunglasses, optical filters and organic optical limiters. While using organic optical limiters is better than other methods, the organic molecules are often environmentally unstable or can be damaged at high intensities.

Technology

The invention is an optical limiter device comprised of nanoparticles of a metallic material, including free electrons that undergo collective oscillations when exposed to the incident light. The nanoparticles could be of metallic materials such as gold and silver.  The device has a structurally rigid transparent medium in which a number of nanoparticles of the metallic material are embedded; and a mechanical support mounting the transparent medium between the incident light and an object. When the device is exposed to incident light above the threshold intensity, the electric field of the nanoparticles becomes enhanced. This enables the absorption of the incident light above the threshold limit while incident light with intensities below the threshold limit passes through.

Advantages

  • It can withstand high laser irradiation without becoming opaque.
  • Environmentally stable and can be used more than once.