ENHANCEMENT OF SPONTANEOUS AND STIMULATED-EMISSION IN THE MICROLASER BY STANDING-WAVE RESONANT EXCITATION

By a new method of momentum-space excitation an increase of the spontaneous emission rate and a large reduction of the microlaser threshold are obtained. The method is demonstrated by an optically excited microlaser filled with europium atoms. The method is general and may be extended to active cavities with any dimension and geometry. Our results on spontaneous emission are interpreted as a demonstration of the first-order interference of the vacuum field