Augustin-Jean Fresnel (1788-1827). 1872 illustration of the French physicist and engineer Augustin-Jean Fresnel. Fresnel is best known for the Fresnel lens used in lighthouses. He qualified as an engineer, but was temporarily removed from his government post in 1815 for supporting the Royalists against Napoleon. During this time he conducted experiments into light. He researched interference and polarisation effects, showing that light must be in the form of transverse waves, as Young and Huygens had suggested, rather than longitudinal waves, like sound.