For a long time physicists thought it was impossible to see anything smaller than about half the wavelength of light.
That’s true if you look at the propagating component of light waves. But light also records smaller sub-wavelength details in its evanescent components, which do not propagate. At least not usually. What [John] Pendry showed [about 10 years ago] was that evanescent components can propagate in a material with a negative refractive index, and he pointed out that a thin film of silver ought to have just the right properties.
Since then, the race has been on to build superlenses. In 2005, Nicolas Fang at the University of Illinois at Urbana-Champaign created one that could record details as small as one-sixth of a wavelength. That was a significant improvement over the diffraction limit, but why not better?
Fang and company recently achieved resolution of only one-twelfth the wavelength of light. The theoretical limit is now pegged at one-twentieth a wavelength, which should be small enough to watch molecules in motion.
The impact of such “transparency” on the micro level opens up fertile realm for speculation: Surely drug designers, among others, are going to want superlenses of their own.
[Story: Technology Review physics arXiv blog; thanks for the tip, dpodolsky; London neon sculpture photo: clry2]
Biologists almost never see the sides of cells. Traditional microscopes only show them the top. Now, though, Vanderbilt scientists have created what’s being called “the world’s smallest periscope”:
The researchers have dubbed their devices “mirrored pyramidal wells.” As the name implies, they consist of pyramidal-shaped cavities molded into silicon whose interior surfaces are coated with a reflective layer of gold or platinum. They are microscopic in dimension – about the width of a human hair – and can be made in a range of sizes to view different-sized objects. When a cell is placed in such a well and viewed with a regular optical microscope, the researcher can see several sides simultaneously.
This low-cost 3D microscopic technique could become standard practice, and become as common as the traditional slide. If only somebody could tell Stephen Boyd or Edmond O’Brien.
A sunflower pollen grain from five vantage points, PhyOrg.
That’s the claim for the Orion Helium Ion Microscope from ALIS (Atomic Level Imaging Source), a Peabody, Massachusetts-based unit of Carl Zeiss SMT AG. It’s a next-generation microsocope that will enable us to see things we’ve never been able to see before, even with the most sophisticated scanning electron microsocope. The company has already sold one unit and has five more under construction. (Via MedGadget.)
I haven’t been this excited since I got my first microscope the Christmas I turned seven…although I don’t suppose I can expect one of these under the tree. Pity. (Illustration from ALIS.)
[tags]microscopy, technology, optics[/tags]