Wisconsin Alumni Research Foundation

Analytical Instrumentation
Analytical Instrumentation
Optimized Nanoresonator Design Signals Breakthroughs in Spectrometry and Device Efficiency
WARF: P160052US01

Inventors: Zongfu Yu, Ming Zhou

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a new structure and method that greatly increase the absorption cross section of small electromagnetic resonators.
An optical resonator is an arrangement of optical components that allows a beam of light to circulate in a closed path. Nanoresonators are a type of optical resonator that can effectively concentrate light into subwavelength dimensions, which is important for applications that require strong light-matter interactions, such as ultrafast photodetectors, single molecule fluorescence imaging and Raman spectroscopy.

Light concentration is key to how well the resonator works and can be evaluated by the ratio between the optical cross section and the geometrical size of a nanoresonator. There are two approaches to improving the concentration ratio: reduce the size of the resonator or increase the optical cross section. However, the first approach is constrained by the minimum size of a useful resonator, and progress using the second approach has been slow because the maximum optical cross section is limited by the resonant wavelength.
The Invention
UW–Madison researchers have developed a new method and structure for increasing the cross section of nanoresonators, thereby improving the concentration ratio of light (or other electromagnetic radiation) and device performance. The key to their approach is that the nanoresonator is surrounded by a material that provides increased light concentration.
  • Imaging sensors and photodetectors in cameras and security devices
  • Multispectral cameras
  • Systems for using nanoresonators as taggants for medical conditions
  • Could enable new technologies in light sensing and solar energy conversion
Key Benefits
  • Increases the absorption cross section of resonators without the drawbacks of conventional lens systems
  • Increases efficiency of photodetectors
  • Improves imaging and photographic quality in settings with weak light
  • Enables strong light-matter interactions necessary in photonics research
  • Can work in conjunction with other solutions that modify the resonators themselves, leading to further improvements and efficiency
  • Can be manufactured at microscopic scales using integrated circuit techniques
  • Broadly applicable to cavity-type resonators as well as other devices that provide energy resonance
Stage of Development
The researchers’ approach achieves more than 1,000σ for a single subwavelength nanoresonator.
Additional Information
  • Zhou M., Shi L., Zi J. and Yu Z. 2015. Extraordinarily Large Optical Cross Section for Localized Single Nanoresonator. Phys. Rev. Lett. 115, 023903.
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