Stimulated emission in Rydberg Matter – a thermal ultra-broadband tunable laser

A tunable laser is built with the condensed excited material Rydberg Matter as the active medium. It is tunable over at least 0.9–16 μm in the infrared. The tuning is almost continuous over this range, due to the broad bands for the forbidden transitions in Rydberg Matter. The beam divergence is low, <10 mrad. The gain for a single pass is 3–7 depending on wavelength. The bandwidth has in some experiments been decreased to 5 cm−1. Absorption spectra are shown both for liquid and gaseous samples. The excitation is purely thermal.