4C9 - Laser pumped microwave emission in excited states of neon

A new technique for producing a controlled excited state population for purposes of radio frequency excited state spectroscopy is illustrated in the experiment reported here. This consists of using the coherent optical field of a gas laser as a pump for a microwave transition between excited states internal to the laser system. From the peak transition frequency observed, we obtain a value, more accurate than previously known, for the energy separation of the and fine structure levels of neon of 26, 359 ± 1 MHz. Since observations are made at microwave frequencies, narrow resonances are directly observed whose widths are determined primarily by collision broadening or natural decay to lower lying levels. Hence, by means of this technique, it is possible to study the dependence of these broadening mechanisms on a variety of experimental conditions.