Fig. 5: Disk orientational biaxiality in a chiral hybrid LC.

a Photon-upconversion-based luminescence confocal images of homeotropic disks dispersed in chiral LC taken in planes perpendicular to \(\hat{{{{\boldsymbol{\chi }}}}}\) with the depths z and directors (\(\hat{{{{\bf{n}}}}}\) and \(\hat{{{{\boldsymbol{\tau }}}}}\)) marked in each depth-resolved optical slice. b The azimuthal angle of the disk normal orientation φ at different depth z obtained for the same sample, with the slices corresponding to (a) indicated by arrows. Dots are the average angular values in each z slice, and their linear fit is given by the red line, consistent with the LC pitch p ≈ 30 μm. The inset illustrates the observed orientational fluctuation of disks (black double arrow) in the frame (\(\hat{{{{\bf{n}}}}},\hat{{{{\boldsymbol{\chi }}}}},\hat{{{{\boldsymbol{\tau }}}}}\)). c Disk azimuthal orientational fluctuation δ = φ–qz and polar orientational fluctuation ζ = π/2–θ within the cholesteric frame (insets), with δ = 0 or ζ = 0 corresponding to the average disk normals' orientation along \(\hat{{{{\bf{n}}}}}\) (red axis). Scale bars are 30 μm.