Optical frequency multiplier

An optical frequency multiplier is a nonlinear optical device in which photons interacting with a nonlinear material are effectively "combined" to form new photons with greater energy, and thus higher frequency (and shorter wavelength). Two types of devices are currently common: frequency doublers, often based on lithium niobate (LN), lithium tantalate (LT), potassium titanyl phosphate (KTP) or lithium triborate (LBO), and frequency triplers typically made of potassium dihydrogen phosphate (KDP). Both are widely used in optical experiments that use lasers as a light source.