Bidimensional nano-optomechanics and topological backaction in a non-conservative radiation force field

We explore the vectorial optomechanical interaction between a nanowire and a focused beam of light. The nanowire is sensitive to the topological variations of the focused laser force field which dramatically modify the phenomenology of the dynamical backaction. The non-conservative topology of the optomechanical interaction is responsible for a novel canonical signature of strong coupling between the nanoresonator mechanical modes, leading to a topological instability. These results have a universal character and illustrate the increased sensitivity of nanomechanical devices towards topologically varying interactions, opening fundamental perspectives in nanomechanics, optomechanics, ultrasensitive scanning probe force microscopy and nano-optics.