Office of Technology Transfer – University of Michigan

Method and Apparatus for Sub-Wavelength Near-Field Focusing of Electromagnetic Waves

Technology #3679

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Researchers
Roberto D. Merlin
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734.764.8202
Patent Protection
US Patent Pending
US Patent 8,003,965

UM File # 3679

Background
The closely-related problems of electromagnetic imaging and focusing beyond Abbe’s diffraction limit (set by .about..lamda./n where .lamda. is the vacuum wavelength and n is the refractive index) have received considerable attention in the past decade, motivated largely by optical studies using sub-wavelength apertures to probe the near field. Techniques such as sharp tip imaging and far-field time reversal mirrors have been proposed to improve the focusing resolution, and factors as large as .about.100 have been achieved in the THz range.
Technology Description
Researchers at the University of Michigan have developed techniques for creating planar sub-wavelength-patterned structures to provide electromagnetic focusing beyond the diffraction limit. When illuminated by an electromagnetic source, these sub-wavelength- patterned structures force the output wave to converge to a sub-wavelength focus at a focal plane in the near field of the structure.
Applications • Near-field microscopy • Near-field optical data storage •Beam shaping •Lithography
Advantages • Small size of near-field focal plane • High resolution