Designed electro-optic Q-switched Nd : YAG laser system

Abstract

Q-switching is one of the techniques to generate high pulse power. By modulating and alternately the optical resonant cavity losses, the Q-factor that defined as the ratio of the energy stored in cavity to energy loss per cycle could be modulated in order to increase pulse power. Usually, by using this technique, a few nanoseconds the pulse duration pulse could be obtained. The flashlamp light is designed to emit the light in duration of 100 to 200 microseconds. During this period, the inversion population is increase dramatically due to the flashlamp pulse as a pumped source. Toward the end of the flashlamp pulse, the inversion population of crystal reaches maximum value and losses of cavity do not change at this moment. Without Q-switching process, the inversion population will decrease slowly and the cavity losses are zero as the result the laser pulses emitted in range of 200 microsecond. Meanwhile, in Q-switch process, the cavity losses are modulated to be zero dramatically. Consequence the inversion population will decrease suddenly and the short pulse as a few nanoseconds could be emitted from laser cavity.