Invisibility has been a fantastical dream for millenia, appearing in cultural myths and legends the world over. A supernatural power, invisibility is prized, conceptually, due to it being ‘perfect stealth’. However, it has never been in the realm of the achievable until recently-in the last decade, and especially in the last two years, invisibility as a practical concept has been looking increasingly likely-and not only at the visible light scale, either.
It turns out that waves of all kinds (ignoring the wave/particle duality for a moment) can be manipulated by various structures-and not only electromagnetic waves, either. In some cases this is an active manipulation, and in some cases it’s a passive manipulation.
Work has been done on cloaking from microwaves as well as against EM waves in general (at least in theory). Researchers in China have done work on partial invisibility, as well. Earlier this year, a team in France did the first scaled testing of a ‘seismic’ invisibility cloak. Late last year, many of the same concepts were applied toward tidal invisibility for oil rigs.