Louis de Broglie
An important figure in the history of quantum mechanics. He was born in a French noble family, and initially he did not intend to become a scientist. After the World War I, he turned to theoretical physics. In his doctrate thesis finished in 1924, he propounded the view that, not only light, but also matter (electron, in particular) should be regarded as having the particle-wave duality. Thus, given an appropriate circumstance, electrons must behave as a wave, although they were always treated as particles in classical mechanics. In a word, de Broglie combined the ideas of Planck and Einstein, and advanced quantum mechanics (new physics) one step further. This was indeed a crucial step; Schroedinger later generalized de Broglie's wave mechanics, and produced the monumental wave equation, the fundamental equation for the quantum mechanics. And experimental confirmation of the wave-character of free electrons was provided by American physicists, Davisson and Germer (1927), as well as by a few other people in the Britain and Japan. Today, even laymen know that electrons can be used for magnifying a tiny thing---electronic microscope---, but when de Broglie first propounded his view, it was almost a "crazy" idea for most people, including many physicists.
De Broglie was awarded the Nobel Prize (physics) in 1929 for this work.
De Broglie's page in the Nobel Foundation