Effects of simmer current on flash-lamp impedance and their combined influence on the output of the Ho,Cr,Tm:YAG laser

The increase in slope efficiency and the reduction of the laser threshold of a flash-lamp-pumped Ho,Cr,Tm:YAG laser that are due to increased flash-lamp efficiency when the current of the dc simmer is increased are described. Investigations of the electrical characteristics of the flash lamp as a function of the simmer current prove that the flash-lamp impedance decreases to a constant value when the dc simmer current is increased. As a consequence an increase of the peak current through the flash lamp is observed, which improves the flash-lamp efficiency.