Intensity scaling of an optically pumped potassium laser

Abstract

A pulsed, optically pumped potassium laser has been demonstrated with output intensity exceeding 7MW/cm2. By using a surrogate pump, heat pipe gain cell, and helium pressure of 2500Torr, the intensity of Diode Pumped Alkali Lasers (DPAL) has been increased by a factor of 38. Bottlenecking due to slow fine structure mixing can be avoided without hydrocarbon buffer gases with as many as 375 lasing photons obtained per potassium atom following a 7.4ns pump pulse. A slope efficiency of 9.4% is achieved and primarily limited by a mismatch between pumped and cavity mode volumes. Laser performance is well described by a three-level, longitudinally averaged model without ionization.