There is provided a cutting element (2) for use in a hair cutting device (10) for cutting hair on a body of a subject, the cutting element comprising: an optical waveguide (4) for coupling to a light source (14) to receive light, wherein the optical waveguide is for contacting hair during a hair cutting operation; a support structure (6) for supporting the optical waveguide (4), wherein a portion (18) of the side wall along at least part of the length of the optical waveguide (4) is in contact with the support structure (6); and a biasing element (8) for applying a biasing force to the optical waveguide (4) and/or at least a part of the support structure (6) to maintain contact between the portion (18) of the side wall of the optical waveguide (4) and the support structure (6).