Charles H. Townes, James Power Gordon and Herbert Jack Zeiger developed the molecular maser, using stimulated emission to amplify or generate coherent microwaves. Their report treats the same device as an amplifier, oscillator and spectrometer. Preparing the molecular excitation and providing resonant feedback turns microscopic transitions between energy levels into a macroscopic signal. The measured frequency stability and narrow spectroscopic resolution showed why the maser could serve as both an instrument for studying molecules and a frequency reference.[ref]
The Maser—New Type of Microwave Amplifier, Frequency Standard, and Spectrometer by James Power Gordon and others. 1955 abstract and molecular-generator mechanism: oscillator stability, spectroscopy and amplification
A physicist.[ref]
https://www.nobelprize.org/prizes/physics/1964/townes/biographical/. Independent professional profile
Portrait of Charles H. Townes
. Woodruff T. Sullivan III; NRAO/AUI Archives, Sullivan Collection; rights NRAO/AUI/NSF. Creative Commons Attribution 4.0 International, with NRAO's displayed source-credit/non-endorsement and third-party-rights qualifications., via Wikimedia Commons. Source.- Molecular Microwave Oscillator and New Hyperfine Structure in the Microwave Spectrum of NH3 by James Power Gordon and others
- Production of coherent radiation by atoms and molecules by Charles Hard Townes
- The Maser—New Type of Microwave Amplifier, Frequency Standard, and Spectrometer by James Power Gordon and others
Articles by others on the same topic
Charles H. Townes (1915-2015) was an American physicist best known for his pioneering work in the development of the laser and maser (Microwave Amplification by Stimulated Emission of Radiation). He shared the 1964 Nobel Prize in Physics with Nikolay Basov and Alexander Prokhorov for their contributions to the field of quantum electronics.