Ammonia maser 2026-10-18
An ammonia maser uses an ammonia molecular beam, maser state selection and a maser cavity to obtain amplification or sustained microwave oscillation. In the 1954 experiment by James Power Gordon, Herbert Jack Zeiger and Charles Hard Townes, a quadrupolar static electric field focused upper-state molecules toward the cavity and deflected lower-state molecules away. The reported ammonia inversion transition lies near .[ref]
Molecular Microwave Oscillator and New Hyperfine Structure in the Microwave Spectrum of NH3 by James Power Gordon and others. pp. 282–283, Fig. 1 and Fig. 2 caption; 23 870 Mc/sec
Maser history 2026-10-18
The 1955 paper by James Power Gordon, Herbert Jack Zeiger and Charles Hard Townes acknowledged Nikolay Basov and Aleksandr Prokhorov's independent proposal.[ref]
The Maser—New Type of Microwave Amplifier, Frequency Standard, and Spectrometer by James Power Gordon and others. p. 1264, Introduction and reference 2
The latter authors' theory paper states that they presented the molecular-generator possibility in May 1952, cites their 1954 publication, and separately cites the Gordon–Zeiger–Townes experimental realization. These are contributions from independent groups.[ref]Theory of the Molecular Generator and Molecular Power Amplifier by Nicolay Gennadiyevich Basov and Aleksandr Mikhailovich Prokhorov. p. 426, historical footnote and references 3–4; manuscript submitted December 10, 1954, English publication October 1956
