Coherence and Noise in the Era of the Maser

It is a commonplace for historians to write that physicists came out of their World War II radar experience with microwave engineering superadded to their knowledge of quantum physics. But what exactly was the content of this new amalgam? How fully was it achieved and by what processes? Publications from the 1950s by four American physicists, Charles Townes, Joseph Weber, Robert Dicke, and Israel Senitzky show that the amalgamation of physics and microwave engineering was far from complete, that it was stimulated by new instrumentation, and that part of the process entailed a re-thinking of the concepts of coherence and noise.