Nonlinear helical dichroism in chiral and achiral molecules

Chiral interactions are prevalent in nature, driving a variety of biochemical processes. Discerning the two non-superimposable mirror images chiral molecule, known as enantiomers, requires interaction with reagent handedness. Circularly polarized light beams often used reagent. Here we demonstrate efficient sensitivity linearly helical carrying an orbital angular momentum ±lħ, which handedness is defined by twisted wavefront structure tracing left- or right-handed corkscrew pattern it propagates space. By probing nonlinear optical response, show that helicity-dependent absorption occurs even achiral molecules and can be controlled. We model this effect considering induced multipole moments light–matter interactions. Design control may open new opportunities chiroptical spectroscopy, light-driven molecular machines, switching situ ultrafast systems magnetic materials. Nonlinear offers detection scheme for both liquid phase.