Technologies are generally described for a nanoparticle filter and system effective to move a nanoparticle from a fluid to a location. In some examples, the method includes providing the fluid including the nanoparticles. In some examples, the method further includes applying a first light to the fluid to create a first plasmon. In some examples, the first plasmon is effective to aggregate the nanoparticles to generate a nanoparticle aggregation. In some examples, the method includes applying a second light to the fluid to create a second plasmon. In some examples, the second plasmon is effective to move the nanoparticle aggregation to a location.