Symmetry-Protected Chiral Sensitivity in Photoionization with Bichromatic Fields

We consider photo-ionization of randomly oriented chiral molecules with bichromatic fields of frequencies \(\omega \) and \(2\omega \) linearly polarized perpendicular to each other. Our symmetry analysis reveals a new type of enantio-sensitive signal in the photoelectron angular distribution which does not change its sign upon reversal of the two-color relative phase, i.e. upon reversal of the instantaneous ellipticity of the field. We provide a numerical estimate of the effect in methyloxirane, and propose an experimental setup for its measurement.