LASER beams are about to get a whole lot more precise. Independent teams have found ways to shrink lasers to nanoscale dimensions in two radically different ways; one creating a spherical laser device 44 nanometres in diameter, while the other can concentrate laser light into a gap just 5 nm across.
Sources of electromagnetic waves cannot normally focus a beam to a size smaller than half its wavelength. For the spectrum of visible light, that’s 190 to 350 nm. To go smaller, the teams used quasiparticles called surface plasmons – fluctuations in the density of electrons on a metal surface…
