Process of producing optical element and optical element

An optical element comprising a only a single cholesteric layer having cholesteric regularity such that the cholesteric layer transmits one of a right-handed circularly polarized component and a left-handed circularly polarized component while reflecting an other of the right-handed circularly polarized component and the left-handed circularly polarized component;

• wherein:
• the cholesteric layer comprises a three-dimensionally polymerized layer formed of a cured radiation-curable liquid crystal;
• the cholesteric layer comprises a plurality of regions at different positions on a surface of the cholesteric layer, each of the plurality of regions having a different thickness, thereby the single cholesteric layer varies in thickness, in a stepwise fashion, along its surface;
• and
• each of the plurality of regions has a different chiral pitch corresponding to its respective thickness such that each of the plurality of regions has a different selective reflection wave range.