text: John Joseph Hopfield (July 8, 1891 – January 8, 1953) was a Polish-American physicist. Hopfield's published research included vacuum ultraviolet spectroscopy and solar ultraviolet spectroscopy. He was the discoverer of the "Hopfield bands" of oxygen and co-discoverer of the "Lyman–Birge–Hopfield bands" of nitrogen.  For about a decade he was an industrial physicist working with technologies for fabricating glass windows, and was the inventor listed on several related patents.