Broadening of spectral absorption lines of atomic potassium under the action of laser radiation

An experimental investigation was made of the broadening of the D lines and of the two-photon absorption line (4S_1/2–6S_1/2) of potassium vapor subjected to ruby laser radiation. A dye laser beam was used as a probe and this made it possible to record simultaneously all three absorption lines. The measurements were carried out for different polarizations and geometries of the exciting and probe radiations. The observed broadening was attributed to the high-frequency Stark effect in the strong field of the incident wave.