  We investigate the possibility that a chiral asymmetry during inflation can
manifest as net circular polarization in photons. Using an example known to
produce a helicity imbalance in fermions, we show that superhorizon photon
modes produced during inflation acquire net circular polarization. Modes that
reenter the horizon around last scattering can thermalize into the Cosmic
Microwave Background while retaining a portion of their net circular
polarization. We also consider the possibility of direct detection of the
circular polarization in the CMB.
