An optical device comprising: a liquid crystal layer having a first major surface , a second major surface and a thickness (T), the first and the second major surfaces extending across a transverse direction (x) and the thickness (T) extending along a direction (z) parallel to a surface normal of the first or the second major surface , the liquid crystal layer comprising a plurality of sub-layers distributed across the thickness (T) of the liquid crystal layer , each sub-layer formed by a single layer of liquid crystal molecules , each of the liquid crystal molecules having a longitudinal axis, each sub-layer comprising: a first domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a first pattern; and a second domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a second pattern; wherein the first domain is spaced apart laterally along the transverse direction (x) from the second domain by a domain gap having a distance (d) between about 10 nm and about 50 nm, wherein the longitudinal axes of the liquid crystal molecules in the domain gap progressively transition from the first pattern to the second pattern; and an alignment layer for the liquid crystal layer , the alignment layer having a first alignment layer domain corresponding to the first domain and a second alignment layer domain corresponding to the second domain, wherein the distance (d) is equal to a gap between the first alignment layer domain and the second alignment layer domain. a liquid crystal layer having a first major surface , a second major surface and a thickness (T), the first and the second major surfaces extending across a transverse direction (x) and the thickness (T) extending along a direction (z) parallel to a surface normal of the first or the second major surface , the liquid crystal layer comprising a plurality of sub-layers distributed across the thickness (T) of the liquid crystal layer , each sub-layer formed by a single layer of liquid crystal molecules , each of the liquid crystal molecules having a longitudinal axis, each sub-layer comprising: a first domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a first pattern; and a second domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a second pattern; a first domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a first pattern; and a second domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a second pattern; wherein the first domain is spaced apart laterally along the transverse direction (x) from the second domain by a domain gap having a distance (d) between about 10 nm and about 50 nm, wherein the longitudinal axes of the liquid crystal molecules in the domain gap progressively transition from the first pattern to the second pattern; and an alignment layer for the liquid crystal layer , the alignment layer having a first alignment layer domain corresponding to the first domain and a second alignment layer domain corresponding to the second domain, wherein the distance (d) is equal to a gap between the first alignment layer domain and the second alignment layer domain. <EOS>