Modeling of dynamic effects in a laser-driven semiconductor switch of high-power microwaves

We investigate non-stationary problems of high-power microwaves penetrating into and reflecting from a semiconductor (silicon) plate. The plate is the base of switch activated by laser-driven photoconductivity and changing its properties when heated by the switched microwave power. Analytical criteria for the stationary solutions of the activated (quasi-metallic) and deactivated (dielectric) states of the switch under the conditions of high-power microwave heating and external cooling are found. Results of numerical simulations are also given for the problems of the switch activation by microwave heating initiated by pulsed laser radiation, which increases the carrier density rapidly. Numerical simulations are carried out by means of the finite-difference time-domain method with the unsplit perfectly matched layer absorbing boundary conditions. We demonstrate various types of solutions which depend on the basic parameters of the problem, namely, microwave field intensity, laser pulse energy and semiconductor doping..