The type of wave that has the shortest wavelength is the gamma wave. Gamma waves are a form of electromagnetic radiation and have the highest frequency and energy among all the waves in the electromagnetic spectrum. They have wavelengths on the order of picometers (10^-12 meters) to femtometers (10^-15 meters). Gamma waves are produced by various nuclear and subatomic processes, such as radioactive decay, nuclear reactions, and particle interactions. They are often associated with high-energy phenomena such as gamma-ray bursts, nuclear explosions, and certain types of radioactive decay.