Fig. 1. Schematics of (a) common cholesteric liquid crystals (CLCs) and (b)–(e) four stacked CLC superstructures. The blue and yellow spirals represent right-handed and left-handed CLC, respectively. D means the thickness of the cell. A means the thickness of the smallest repeating unit. The z-axis is along the helical axis.

Fig. 2. (a), (f) The reflection spectrum and the phase of E_x component of the light reflected from right-handed CLC. (b)–(e) The reflectance spectra and (g)–(j) the polarization of the light reflected from four stacked CLC models. The stacked CLCs are (b), (g) A = D, (c), (h) A = D/2, (d), (i) A = D/4, and (e), (j) A ≈ 0, respectively.

Fig. 3. The optical properties of (a), (f), (k) the right-handed CLC and the stacked CLCs with (b), (g), (l) A = D, (c), (h), (m) A = D/2, (d), (i), (n) A = D/4, and (e), (j), (o) A ≈ 0, respectively. (a)–(e) The reflectance spectra after an x-directional analyzer dependent on α and λ. (f)–(j) The section at α = π/2, and (k)–(o) the section at λ = 633 nm [blue dashed lines in (a)–(e)], where the red/blue curves represent the reflectance without analyzer/with an x-directional analyzer, respectively.

Fig. 4. The polarization distribution and diffracted optical field of the three patterned CLC stacks: (b)–(e) A = D, (f)–(i) A = D/4, and (j)–(m) A ≈ 0. (a) The designed surface CLC alignment and phase pattern. (b), (f), (j) Schematics of three stacked CLC models, corresponding to Figs. 1(b), 1(d), 1(e), respectively. (c), (g), (k) Reflectance spectra of the three CLC models corresponding to Figs. 2(b), 2(d), 2(e), respectively. The polarization distribution and the diffracted optical field with/without analyzer for the generated vector beams at (d), (h), (l) 633 nm and (e), (i), (m) 650 nm, respectively. The white/yellow arrows represent the incident polarizer/analyzer, respectively. The white dashed lines indicate the position of π/2 polarization.