Bragg-Berry cavities: orbital angular momentum manipulation of broadband light beams

摘要: Liquid crystals have emerged as promising materials in the field of modern optics and photonics. Their unique properties make them promising for various applications, including light beam shaping and the generation of optical vortices characterized by orbital angular momentum. Cholesteric liquid crystals (CLCs) possess a spiral supramolecular structure; thus, they exhibit a Bragg reflection of circularly polarized light at the cholesteric pitch p~ λ/n, where λ is the light wavelength, and n is the average refractive index. The handedness of this reflection corresponds to the chirality of the CLC.By incorporating patterned substrates, CLC cells can function as Bragg-Berry mirrors, effectively combining the effects of reflection and Pancharatnam-Berry phase modulation in a broad spectral range due to spin-to-orbital angular momentum conversion [1]. In the case of a topological defect structure on the substrates of the CLC …