Ultranarrowband tunable dye laser for new approaches to atomic spectroscopy

This report summarizes recent progress in the development and improvement of tunable laser systems for novel approaches to atomic and molecular spectroscopy, and in particular for new precision studies of atomic hydrogen. It reports on: (a) The development of a highly monochromatic, powerful tunable dye laser system, combining a single-frequency CW dye laser oscillator with a multistage pulsed dye laser amplifier. (b) The generation of CW single-frequency coherent radiation near 243 angstrom by summing the frequencies of a Kr ion laser and a CW dye laser in cooled ADP. In addition, the report summarizes three experiments, exploring new coherent light techniques for sensitive high resolution spectroscopy of atoms and molecules. These are (c) The first demonstration of Doppler-free laser polarization spectroscopy, a new technique, which can greatly exceed the sensitivity of saturated absorption spectroscopy. The Stark splitting of the hydrogen Balmer beta line in a glow discharge has been resolved. (d) A demonstration of polarization labeling of molecular sodium. This new technique simplifies the unraveling of complex absorption spectra by identifying lines with a common lower state. (e) High resolution two-photon spectroscopy of the excited state of normal and deuterated benzene. The observed rotational contours have been reported by computer fits, yielding accurate molecular constants.