Amplifications in chiroptical spectroscopy, optical enantioselectivity, and weak value measurement

Chiroptical spectroscopy utilizing left- and right-handed electromagnetic fields has been used to obtain stereochemical information on chiral molecules in condensed phases. However, due to weak signals (10−6 to 10−2 of absorption), not only are accurate measurements of chiroptical signals difficult but also preferential excitation of one type of handed molecule over the other using chiral fields (i.e., optical enantioselectivity) is limited. Recently, methods have been developed to enhance chiroptical signals and optical enantioselectivity by properly controlling polarization states, designing detection schemes, and modifying spatial properties of chiral fields. In the physics community, similar enhancements have been introduced using a quantum mechanical theory called “weak value measurement.” Here we provide examples of these techniques, corresponding enhancement mechanisms, and more importantly connections between them.