Near-perfect discrimination of chiral molecules based on steady states of a cavity mode

We propose a protocol to realize discrimination of chiral molecules based on steady states of a cavity mode. Using the closed-loop three-level structure of a molecule, an effective Hamiltonian of the molecule-cavity-coupled system is derived. The effective Hamiltonian is similar to a linear driving of the cavity mode, but the driving strength depends on the chirality of the molecule. In the presence of photon loss, the cavity behaves like a driven damped harmonic oscillator, and it will evolve to different steady coherence states according to the chirality of the molecule. By selecting proper parameters, it is possible to obtain steady coherence states with large-enough amplitudes that can be well determined by homodyne measurements on the cavity. Consequently, the chirality of the molecules can be discriminated near perfectly, according to the measurement result of the cavity. Numerical simulations show that the protocol is insensitive to the systematic errors of the control fields and the energy relaxation of the molecules. Therefore, the protocol may provide an effective approach to realize chirality discrimination with high accuracy.