Picture of the month: Good humour at a hair’s breadth from the Institute of Applied Physics

Even a small smile can make a big difference. For maximum effect, our picture of the month is a particularly small smile. 5 micrometres wide, to be precise. Not only does the smiley fit comfortably on a strand of hair, but the researchers at the QuantumFrontiers Cluster of Excellence, together with pupils, have engraved it on a single strand of hair. The precision tool, which uses a focused ion beam and a super-magnifying glass, is based at the LENA research centre and is otherwise used to advance research on the smallest possible scale.

The 5 micrometre wide smiley can even fit on a hair. Image credit: Markus Etzkorn/Institute of Applied Physics