Hyperfine structure investigation of ¹⁸⁷Os atomic levels via optical-optical double resonance

Optical-optical double resonance spectroscopy has been applied to measure the hyperfine structure of spectral line pairs of atomic osmium in the visible wavelength range. In the experiments, enriched isotope samples of either ¹⁸⁹Os or ¹⁸⁷Os were used. In this way, the magnetic dipole hyperfine interaction constants of the odd isotope ¹⁸⁷Os were determined for seven levels of even parity and two levels of odd parity.