  We show, both classically and quantum mechanically, enantioselective
orientation of gas phase chiral molecules excited by laser fields with twisted
polarization. Counterintuitively, the induced orientation, whose direction is
laser controllable, does not disappear after the excitation, but stays
approximately constant long after the end of the laser pulses, behavior unique
to chiral systems. We computationally demonstrate this long-lasting orientation
using propylene oxide molecules (${\rm CH_{3}CHCH_{2}O}$, or PPO) as an
example, and consider two kinds of fields with twisted polarization: a pair of
delayed cross-polarized pulses, and an optical centrifuge. This novel chiral
effect opens new avenues for detecting molecular chirality, measuring
enantiomeric excess and separating enantiomers with the help of inhomogeneous
external fields.
