“Superlenses” could lead to movies of molecules

Tom Marcinko @ 11-06-2009

neonFor 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]

New carbon dioxide molecule found to heat Venus more

Tomas Martin @ 12-10-2007

The green planet may tell us more about how the greenhouse effect worksA big team of astronomers studying Venus’ atmosphere have found a new type of heavier carbon dioxide molecule that absorbs more heat than the one more commonly found on Mars or Earth. The molecule, which is believed to have two additional neutrons in one of its oxygen atoms, allows it to absorb an additional infrared wavelength of 3.3 microns, which is what tipped the teams off to the discovery. They believe this is part of the reason Venus has such a hot atmosphere – the bigger percentage of these molecules creates an even bigger Greenhouse Gas effect than normal CO2.

As soon as I read this article comparing Mars’ cold atmosphere to Venus’ hot one in relation to the quantities of this new molecule, I immediately thought of Kim Stanley Robinson’s ‘Red Mars’. If this gas contributes more global warming than normal CO2, in the future it may be a very valuable tool if we ever came to terraform our red neighbour.

[link and image via ScienceDaily]