A diffraction grating (1150, 1358, 1400, 1604, 1750A, 1750B, 1750C) comprising: a cholesteric liquid crystal, CLC layer (1004, 1008, 1158, 1358A, 1358B, 1404, 1424) comprising a plurality of chiral structures (1012-1,..., 1012-i, 1162-1,.., 1162-i), wherein each chiral structure comprises a plurality of liquid crystal molecules (1012-1-1,..., 1012-i-j, 1162-1-1,..., 1162-i-j) that extend in a layer depth direction (z) by at least a helical pitch (p, p1, p2, p3, p4) and are successively rotated in a first rotation direction, wherein the helical pitch (p, p1, p2, p3, p4) is a length in the layer depth direction (z) corresponding to a net rotation angle (φ1, cp2,...φi) of the liquid crystal molecules of the chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) by one full rotation in the first rotation direction, and wherein arrangements of the liquid crystal molecules (1012-1-1,..., 1012-i-j, 1162-1-1,..., 1162-i-j) of the chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) vary periodically in a lateral direction (x) perpendicular to the layer depth direction (z), wherein the chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) comprise: a first plurality of chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) each comprising a plurality of first liquid crystal molecules that extend in a layer depth direction by at least a first helical pitch and are successively rotated in the first rotation direction; and a second plurality of chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) each comprising a plurality of second liquid crystal molecules that extend in the layer depth direction by at least a second helical pitch and are successively rotated in the first rotation direction, wherein the second helical pitch is different from the first helical pitch. a cholesteric liquid crystal, CLC layer (1004, 1008, 1158, 1358A, 1358B, 1404, 1424) comprising a plurality of chiral structures (1012-1,..., 1012-i, 1162-1,.., 1162-i), wherein each chiral structure comprises a plurality of liquid crystal molecules (1012-1-1,..., 1012-i-j, 1162-1-1,..., 1162-i-j) that extend in a layer depth direction (z) by at least a helical pitch (p, p1, p2, p3, p4) and are successively rotated in a first rotation direction, wherein the helical pitch (p, p1, p2, p3, p4) is a length in the layer depth direction (z) corresponding to a net rotation angle (φ1, cp2,...φi) of the liquid crystal molecules of the chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) by one full rotation in the first rotation direction, and wherein arrangements of the liquid crystal molecules (1012-1-1,..., 1012-i-j, 1162-1-1,..., 1162-i-j) of the chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) vary periodically in a lateral direction (x) perpendicular to the layer depth direction (z), wherein the chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) comprise: a first plurality of chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) each comprising a plurality of first liquid crystal molecules that extend in a layer depth direction by at least a first helical pitch and are successively rotated in the first rotation direction; and a second plurality of chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) each comprising a plurality of second liquid crystal molecules that extend in the layer depth direction by at least a second helical pitch and are successively rotated in the first rotation direction, wherein the second helical pitch is different from the first helical pitch. a first plurality of chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) each comprising a plurality of first liquid crystal molecules that extend in a layer depth direction by at least a first helical pitch and are successively rotated in the first rotation direction; and a second plurality of chiral structures (1012-1,..., 1012-i, 1162-1,..., 1162-i) each comprising a plurality of second liquid crystal molecules that extend in the layer depth direction by at least a second helical pitch and are successively rotated in the first rotation direction, wherein the second helical pitch is different from the first helical pitch.