Electron emission from insulator and semiconductor surfaces by multiphoton excitation below the optical damage threshold

The shape of acoustic pulses excited in crystalline silicon during absorption of Nd³⁺ YAG laser radiation was studied as a function of incident light intensity. It was revealed that the amplitude of the dilatation wave is saturated while the duration of the compression pulse is shortened. A theoretical model is suggested which explains the above experimental facts by a decrease in the time of Auger recombination for nonequilibrium carriers with an increase in their concentration for higher intensity of the optical excitation. The value of the Auger constant obtained from the experiment is 5×10^–31 cm⁶s^–1.