Study of Potassium DPAL Operation in Pulsed and CW Mode

This paper presents the results of our experiments on development of the efficient hydrocarbon free Diode Pumped Alkali Laser based on potassium vapor buffered by He gas at 600 Torr. We studied the performance of this laser operating in pulsed mode with pulses up to 5 ms long at different pulse energies and cell temperatures. A slope efficiency of more than 50% was demonstrated with total optical efficiency about 30% for the pump pulses with duration about 30 micrometers. For the longer pump pulses the DPAL efficiency degraded in time with a characteristic time in the range from 0.5 ms to 4.5 ms depending on the pump pulse energy and cell temperature. The recorded spectrum of the side fluorescence indicates that multi-photon excitation, energy pooling collisions and ionization may be strong candidates for explaining the observed performance degradation. 22 Sep 2014, 25 Sep 2014,