Focusing Beyond the Diffraction Limit with Far-Field Time Reversal

@article{Lerosey2007FocusingBT,
  title={Focusing Beyond the Diffraction Limit with Far-Field Time Reversal},
  author={Geoffroy Lerosey and Julien de Rosny and Arnaud Tourin and Mathias Fink},
  journal={Science},
  year={2007},
  volume={315},
  pages={1120 - 1122}
}
We present an approach for subwavelength focusing of microwaves using both a time-reversal mirror placed in the far field and a random distribution of scatterers placed in the near field of the focusing point. The far-field time-reversal mirror is used to build the time-reversed wave field, which interacts with the random medium to regenerate not only the propagating waves but also the evanescent waves required to refocus below the diffraction limit. Focal spots as small as one-thirtieth of a… 
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References

SHOWING 1-10 OF 25 REFERENCES
Overcoming the diffraction limit in wave physics using a time-reversal mirror and a novel acoustic sink.
TLDR
This work reports the first experimental result obtained with an acoustic sink where a focal spot size of less than 1/14th of one wavelength is recorded.
Time reversal of electromagnetic waves.
TLDR
The first experimental demonstration of time-reversal focusing with electromagnetic waves in a high-Q cavity is reported, with the wave found to converge to its initial source and is compressed in time.
Time reversal of wideband microwaves
In this letter, time reversal is applied to wideband electromagnetic waves in a reverberant room. To that end a multiantenna time reversal mirror (TRM) has been built. A 150MHz bandwidth pulse at a
Time-reversal of ultrasonic fields. III. Theory of the closed time-reversal cavity
  • D. Cassereau, M. Fink
  • Physics
    IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
  • 1992
TLDR
The time-reversal focusing process using a closed cavity in a weakly inhomogeneous medium is compared with more classical techniques to compensate wavefront distortions, thus illustrating the focusing improvement due to the time- reversal method.
Near-Field Microscopy Through a SiC Superlens
TLDR
This work combines the advantages of both techniques and demonstrates a novel imaging system where the objects no longer need to be in close proxim-ity to a near- field probe, allowing for optical near-field microscopy of subsurface objects at sub-wavelength-scale lateral resolution.
How to Build a Superlens
Conventional lenses are subject to the diffraction limit, which means that they cannot resolve objects placed closer together than one-half of the wavelength of the illuminating light. As Smith
Negative refraction makes a perfect lens
  • Pendry
  • Physics
    Physical review letters
  • 2000
TLDR
The authors' simulations show that a version of the lens operating at the frequency of visible light can be realized in the form of a thin slab of silver, which resolves objects only a few nanometers across.
Experimental Verification of a Negative Index of Refraction
TLDR
These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root ofɛ·μ for the frequencies where both the permittivity and the permeability are negative.
Near-Field Optics: Microscopy, Spectroscopy, and Surface Modification Beyond the Diffraction Limit
TLDR
The near-field optical interaction between a sharp probe and a sample of interest can be exploited to image, spectroscopically probe, or modify surfaces at a resolution inaccessible by traditional far-field techniques, resulting in a technique of considerable versatility.
Super-resolution imaging through a planar silver layer.
TLDR
Experimental confirmation that super-resolution imaging can be achieved using a 50-nm thick planar silver layer as a near-field lens at wavelengths around 365 nm agrees well with finite-difference time domain (FDTD) simulations.
...
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