We use a diode laser locked to a Rb transition as the frequency reference, along with a scanning Michelson interferometer, to make precise frequency measurements of atomic energy levels. The high precision is possible because the Rb reference frequency is known with submegahertz accuracy. We measured the frequencies of the D lines in K and obtained the following values: 12985.169 60(20) cm1 for the 4P 1/2 state (D 1 line), 13042.875 95(21) cm1 for the 4P 3/2 state (D 2 line), and 57.706 35(24) cm1 for the 4P 3/2 4P 1/2 fine-structure interval. The errors represent approximately an order-of-magnitude improvement over tabulated values.
© 2004 Optical Society of America
Ayan Banerjee, Dipankar Das, and Vasant Natarajan, "Precise measurements of atomic energy levels: D lines and fine-structure interval in K," J. Opt. Soc. Am. B 21, 79-82 (2004)