Common names for a wedge include wedged window and thick or thin prisms. Used as a wedged window, a wedge can control the direction of back-reflected light at each surface. Applications for wedged windows, as opposed to standard plane-parallel windows, can be found in lasers and interferometers. As a thick or thin prism, a wedge can be used to disperse light into its constituent colors. Color analyzers and spectrographic instruments contain prisms or diffraction gratings to bend light of different colors into different angles for analysis.