Second harmonic Circular Dichroism in Achiral Nanostructures

\nWe theoretically show that under circularly polarized plane wave or vortex beam illumination, the second-harmonic circular dichroism is possible even if the nanostructure is achiral. The interplay of nanostructure’s and crystalline lattice’s symmetries leads to specific conditions for observation of the circular dichroism, which can be expressed by a short formula. This can be particularly important for chiral sensing enhancement with nanostructure, where it is important to separate the signal from the nanostructure itself.\n