Room temperature source of single photons of definite polarization

A definite polarization in fluorescence from single emitters (dye molecules) at room temperature is demonstrated. A planar-aligned, nematic liquid-crystal host provides definite alignment of single dye molecules in a preferred direction. Well-defined polarized fluorescence from single emitters (single photon source) is important for applications in photonic quantum information. Polarized single-photon sources based on single emitters, for example, are key hardware elements both for absolutely secure quantum communication and quantum computation systems.