IMPACT OF LASERS ON PRIMARY FREQUENCY STANDARDS AND PRECISION SPECTROSCOPY

Lasers available at new wavelengths, powers, linewidths, and stabilities have made possible advances in precision atomic frequency standards and spectroscopy. Laser spectrometers with resolving power exceeding 1011 have been constructed and used to measure the photon recoil structure of spectral lines and in new tests of relativity. Recent progress in frequency stabilation methods and in laser-cooled ions indicates the possibility of an optical frequency standard with an accuracy and stability of less than 10-15. Diode lasers may enable the construction of an optically-pumped cesium standard with an order-of-magnitude improvement in accuracy over existing primary standards