HISTORY OF ATOMIC FREQUENCY STANDARDS: A TRIP THROUGH 20th CENTURY PHYSICS

摘要

The opening year of the 20th century brought with it Planck's bold announcement of the quantum nature of radiation energy interacting with matter; an avalanche of unprecedented insights into the physics of atoms and molecules followed during the years leading up to World War II and continued during the period after the war. These remarkable scientific advances, in combination with extraordinary advances in technologies accelerated by war and defense related programs provided a broad foundation for the development of atomic and molecular frequency standards with a number of approaches reflecting different scientific research methodologies. This paper will relate the history of atomic and molecular frequency standards development in a framework that includes linkages with scientific advances that underlie the progress. As the century draws to a close, the rate of investment in the further refinement of atomic and molecular frequency standards and the related practical research is much reduced; however, ongoing scientific advances continue to provide a very high level of potential for improvements well into the next century. But perhaps it is even more important to note that rapidly expanding applications in areas that affect larger and more widely distributed user populations will provide the most important driving forces affecting future demands for this complex technology.