Free-space outcoupling of OAM beams from Bloch surface waves

Beams carrying Orbital Angular Momentum are produced from multilayered structures upon excitation of surface modes. Such structures are axially-symmetric and exhibit a high Local Density of States to facilitate radiation coupling from localized, possibly individual emitters located on the surface, such as q-dots or defected 2D materials. Polarization-sensitive, free-space diffraction of surface modes is obtained after proper decoration of dielectric multilayers with chiral metasurfaces.