Abstract
We demonstrate the generation of spectrally tunable phase-dependent wavefronts, using the 2D Airy as the primary test case, via a polymer-stabilized cholesteric liquid crystal (PSCLC) element. Specifically, we use a novel spatial light modulator (SLM) based projection system to photo-align the initial helix angle landscape of the PSCLC so that it imparts the appropriate cubic phase profile to the reflected beam. This element is spectrally selective, with a reflection bandwidth of ≈ 100 nm, and electrically tunable from λ = 530 nm to 760 nm. Under both green and red laser illumination, the element is shown to conditionally form an Airy beam depending on the position of the electrically tailored reflection band. We briefly demonstrate the generality of this approach by producing PSCLC elements which form a computer-generated hologram and a higher-order Mathieu beam.
Highlights
Cholesteric liquid crystals (CLCs) form chiral Bragg reflectors via self-assembly
It has been shown that variations in the initial helix angle of the CLC impart a geometric or Pancharatnam-Berry phase modulation on the reflected beam [1, 2]
We propose here that this approach is compatible with the wide range of previously demonstrated techniques for dynamic tuning, broadening, and switching of reflection bands, in polymer-stabilized cholesteric liquid crystal systems
Summary
Cholesteric liquid crystals (CLCs) form chiral Bragg reflectors via self-assembly. Recently it has been shown that variations in the initial helix angle of the CLC impart a geometric or Pancharatnam-Berry phase modulation on the reflected beam (illustrated in Fig.1) [1, 2]. It has been shown that variations in the initial helix angle of the CLC impart a geometric or Pancharatnam-Berry phase modulation on the reflected beam (illustrated in Fig.1) [1, 2].
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