Millimeter wave control using a plasma filled photonic crystal resonator

The manipulation of millimeter-scale microwaves is studied using plasma discharges formed within a vacancy defect of a two-dimensional photonic crystal consisting of a hexagonal lattice of sapphire rods. When an externally driven discharge pulse is generated within the defect, the photonic crystal response is to transmit microwave pulses with variable properties, such as pulse widths and delays as small as 300 ns. Without external drive of the discharge, the device is also shown to behave as a nonlinear power limiter and attenuates the incoming power by 10–15 dB in less than one microsecond when the input power surpasses the threshold of microwave breakdown within the cavity, even at modest incident power of order 1 W. Lastly, by combining external pulse drive with high incident field power but below self-ignition limits, we show using a simple model analysis of the resonator response that the plasma formed spans a wide range of plasma densities, dependent upon the sustaining microwave frequency. (paper)