Wood, Robert Williams (1868–1955),
American physicist. Wood spent the bulk of his scientific career at Johns Hopkins University, first as professor and later as research professor of experimental physics. His greatest contributions were in optics, especially spectroscopy, in which he obtained experimental results of prime importance for the advancement of atomic physics. A recognized authority on the optical properties of gases and vapors, especially sodium vapor, he did fundamental work on fluorescence in vapors. Equally important was his research on the effect of electric and magnetic fields on spectral lines. With his improvements in the diffraction grating he greatly stimulated research in spectroscopy by other scientists. Other areas of Wood's research included color photography, the photographing of sound waves, the properties of ultrasonic vibrations, and criminalistics. During World War II he served as a consultant for the Manhattan project. He also had numerous inventions to his credit. In 1903 he first used a filter of nickel-containing glass to remove visible light from a beam of radiation, producing a beam consisting only of ultraviolet light. Lamps incorporating such filters have since been named after him.