K9 Littrow Prisms are optical components fabricated from K9 crown glass with high refractive homogeneity and precision-polished surfaces. The Littrow configuration is designed so that light enters and exits along the same path under specific wavelengths, enabling wavelength-selective reflection. These prisms are manufactured with tight angular tolerances and surface quality control to ensure accurate optical feedback behavior. They are widely used in laser cavities, spectrometers, and wavelength tuning systems. Optical performance depends on refractive index stability and surface flatness.