Alchemy with light

摘要

You don't often see claims of "unexpected and stunning new physical phenomena" in the abstract of a reputable scientific paper. But the latest report by photonics crystal pioneer John Joannopoulos and his group at MIT, soon to be published in Physical Review Letters, does not disappoint. The researchers document the ultimate control over light: a way to shift the frequency of light beams to any desired colour, with near 100 per cent efficiency.