Experimental physicist Matthias Wollenhaupt enjoys working with alkali metals - he explains why here.

"Alkali metals, especially the element potassium, are a particular favourite in my research group (ULTRA). The potassium atom has only one outer electron and therefore behaves in many respects physically in the same way as the hydrogen atom, but is much easier to access experimentally. We use ultrashort femtosecond laser pulses to control the ultrafast quantum mechanical process of photoionisation in potassium atoms. We recently succeeded in generating photoelectrons with sevenfold symmetry and in the form of a vortex."