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These are lenses that operate on a principle of "negative refractive
index". They are able to break the diffraction limit that was believed to limit the resolution achievable in an optical system based on its aperture and the wavelength observed: Angular resolution. http://en.wikipedia.org/wiki/Angular...on#Explanation Already they are being used to create sub-diffraction limit images in microscopy: Metamaterials found to work for visible light. Ames Laboratory researchers have found the first metamaterial known to work for visible light, announcing the discovery in the Jan. 5 issue of Science. 14:54, January 04, 2007 http://www.physorg.com/news87144852.html 'Superlens' has its reach extended. Tom Simonite 17:23 01 February 2007 NewScientist.com news service http://www.newscientisttech.com/arti...-extended.html New superlens opens door to nanoscale optical imaging, high-density optoelectronics. 22.04.2005 A group of scientists at the University of California, Berkeley, is giving new relevance to the term "sharper image" by creating a superlens that can overcome a limitation in physics that has historically constrained the resolution of optical images. http://www.innovations-report.de/htm...cht-43432.html Sub-Diffraction-Limited Optical Imaging with a Silver Superlens. Nicholas Fang, Hyesog Lee, Cheng Sun, Xiang Zhang* Science, 22 April 2005: Vol. 308. no. 5721, pp. 534 - 537. Recent theory has predicted a superlens that is capable of producing sub-diffraction-limited images. This superlens would allow the recovery of evanescent waves in an image via the excitation of surface plasmons. Using silver as a natural optical superlens, we demonstrated sub-diffraction-limited imaging with 60-nanometer half-pitch resolution, or one-sixth of the illumination wavelength. By proper design of the working wavelength and the thickness of silver that allows access to a broad spectrum of subwavelength features, we also showed that arbitrary nanostructures can be imaged with good fidelity. The optical superlens promises exciting avenues to nanoscale optical imaging and ultrasmall optoelectronic devices. http://www.sciencemag.org/cgi/content/full/308/5721/534 However, the superlenses work by detecting near field light waves which are quite close to the object being observed, within a light wavelength. A key question is can their use be extended to work for objects that are far away, which would be required for astronomy. There is some research on possible ways this might work: Telescope resolution using negative refractive index materials. Jack L. May and Tony Jennetti Northrop Grumman Mission Systems (USA). Proceedings of SPIE -- Volume 5166 UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts, Howard A. MacEwen, Editor, January 2004, pp. 220-227 "Concepts are presented for using negative refractive index (NRI) materials to design parabolic reflector telescopes and antennas with resolutions significantly better than the diffractions limit. The main question we are attempting to answer is can negative refractive material be used to improve performance of parabolic systems even when the signal or light source is far away and no evanescent fields are present when they arrive at the parabolic reflector. The main approach is to take advantage of any knowledge that we have to recreate the evanescent fields. Fields are then adapted to improve a performance measure such a sharper focus or antenna rejection of interference. A negative refraction index lens is placed between the conventional reflector and focal plane to shape the point spread function. To produce telescope resolutions that are better than the diffraction limit, evanescent fields created by the reflection off of the parabolic surface are amplified and modified to generate fields that sharpen the focus. A second approach use available knowledge of an emitting aperture to synthesize a field at a distance that matches as closely as possible the field of the emitting aperture. The yet unproven conclusion is that techniques can be developed that will improve antenna and telescopes resolution that is better than the diffraction limit." http://link.aip.org/link/?PSISDG/5166/220/1 [Abstract only] If this succeeds then telescope apertures will only need to be a fraction of their current size to achieve the same resolution. This will be fundamentally important for space based telescopes. The revolution in medicine and biology the superlens will allow has to do with the confirmation of a hypothesized, but controversial, form of life, the nanobacteria. I believe the nanobacteria will be proven to exist and will be found to be pathogens for disease in humans. There are for example some diseases that give the appearance of infectious disease but for which no infectious agent has been identified. One such case is for example kidney stones. Some papers have been written suggesting nanobacteria as their cause. Very small nanoscale objects were seen in connection with the kidney stones but these objects could not be confirmed as being alive. The problem is these nanoscale objects can be seen for example with electron microscopes, but this kills any putative life forms being examined. The new superlens will allow these nanoscale objects to be observed in optical wavelengths, at smaller sizes than the wavelengths used, and as I say alive. You could for example do spectroscopy on them to confirm they contain the organic molecules for life, and perhaps as well observe their life cycle in real time. The confirmation of a new form of life previously believed impossible will certainly be revolutionary. The team that confirms them for example I believe will be deserving of a Nobel prize. It's just a matter of time, a short time. Bob Clark |
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