A polarization conversion device includes a geometric phase grating and an angular selective waveplate. The geometric phase grating includes a first liquid crystal layer and is configured to diffract a unpolarized or partially polarized incident light beam into a first light beam and a second light beam (e.g., in two different diffraction orders). The first light beam is characterized by a first polarization state and propagates in a first direction. The second light beam is characterized by a second polarization state and propagates in a second direction. The angular selective waveplate includes a second liquid crystal layer, and functions as a zero or full-wave plate for the first light beam incident in the first direction and a half-wave plate for the second light beam incident in the second direction.