  Enantiodetection is an important and challenging task across natural science.
Nowadays, some chiroptical methods of enantiodetection based on
decoherence-free cyclic three-level models of chiral molecules can reach the
ultimate limit of the enantioselectivities in the molecular responses. They are
thus more efficient than traditional chiroptical methods. However, decoherence
is inevitable and can severely reduce enantioselectivities in these advanced
chiroptical methods, so they only work well in the weak decoherence region.
Here, we propose an enantioselective switch on the radiation of dissipative
chiral molecules and develop a novel chiroptical method of enantiodetection
working well in all decoherence regions. In our scheme, radiation is turned on
for the selected enantiomer and simultaneously turned off for its mirror image
by designing the electromagnetic fields well based on dissipative cyclic
three-level models. The enantiomeric excess of a chiral mixture is determined
by comparing its emissions in two cases, where the radiations of two
enantiomers are turned off respectively. The corresponding enantioselectivities
reach the ultimate limit in all decoherence regions, offering our scheme
advantages over other chiroptical methods in enantiodetection. Our work
potentially constitutes the starting point for developing more efficient
chiroptical techniques for enantiodection in all decoherence regions.
