This is an optomechanical resonator, which basically means that the oscillations from light that the structure absorbs can cause it to vibrate. According the authors of the article, Tal Carmon and Kerry J. Vahala of the California Institute of Technology, published in Physical Review Letters, the color bands represent distortion of a micrometre-sized silica sphere mounted at the top of a tiny pillar.
I haven’t found anything in the paper to say what the oscillating sphere might be used for, but tiny oscillators are important for all kinds of devices, including the CPU at the heart of your PC, communication systems, and measuring instruments. But I’m only posting this today because it looks cool.