  We proposed and demonstrated a scheme of surface emitting circularly
polarized light source by introducing strong imbalance between left- and
right-circularly polarized vacuum fields in an on-waveguide chiral grating
structure. We observed circularly polarized spontaneous emission from InAs
quantum dots embedded in the wave guide region of a GaAs-based structure.
Obtained degree of polarization reaches as large as 25% at room temperature.
Numerical calculation visualizes spatial profiles of the modification of vacuum
field modes inside the structure with strong circular anisotropy.
