'Blade' ion trap in ultra-high vacuum system. If you look closely, you can see a single strontium ion in the centre of the trap, between the tips of the two 'needle' electrodes. The tips of the needles are separated by 2.3mm. (Note that this is an actual photo of ion and trap, not a montage of separate photos; a long camera exposure time, 30 seconds, was used to capture the faint fluorescence from the single ion.)