Abstract: A computer system displays a first object that includes at least a first portion of the first object and a second portion of the first object and detects a first gaze input that meets first criteria, wherein the first criteria require that the first gaze input is directed to the first portion of the first object in order for the first criteria to be met. In response, the computer system displays a first control element that corresponds to a first operation associated with the first object, wherein the first control element was not displayed prior to detecting that the first gaze input met the first criteria, and detects a first user input directed to the first control element. In response to detecting the first user input directed to the first control element, the computer system performs the first operation with respect to the first object.

Abstract: A device for controlling the polarization state of transmitted light comprises first and second cell walls enclosing a layer of a chiral liquid crystal material. The material has a uniformly orientated helical axis in the absence of an applied field, and electrodes for applying an electric field substantially normal to the helical axis. An applied electric field flexoelectrically couples to the molecules, causing distortion of the helical structure and hence changes the bulk birefringence of the cell.

Abstract: A device for controlling the polarization state of transmitted light comprises first and second cell walls enclosing a layer of a chiral liquid crystal material. The material has a uniformly orientated helical axis in the absence of an applied field, and electrodes for applying an electric field substantially normal to the helical axis. An applied electric field flexoelectrically couples to the molecules, causing distortion of the helical structure and hence changes the bulk birefringence of the cell.

Abstract: A tuneable laser device comprises first and second cell walls enclosing a layer of a liquid crystal material having a helical axis substantially normal to the inner surfaces of the cell walls in the absence of an applied field. The liquid crystal contains a fluorescent, phosphorescent, luminescent or rare-earth dye. The device includes electrodes for applying a transverse electric field substantially normal to the helical axis. The invention also provides a method of electrically adjusting the peak wavelength of a photonic band edge laser comprising a chiral nematic liquid crystal material having a helical axis and a fluorescent, phosphorescent, luminescent or rare-earth dye therein and optically pumped by a suitable light source. The method comprises applying an electric field substantially perpendicular to the helical axis so as to deform the helix by means of the flexoelectric effect.