Field emitter arrays (FEAs) have been investigated as potential cold cathodes in variety of applications such as flat-panel displays and image sensors, microwave and further high frequency vacuum electronic devices. The density modulated electron beam (a train of electron bunches) at high frequency generated directly from the cathodes offers opportunities for dramatic improvements in performance of microwave vacuum electronic devices. The paper discusses the emission characteristics and optical response of gated p-type silicon field emitter arrays under irradiation of laser pulses.