Millimeter Wave Plasma Formation Within a 2D Photonic Crystal

Experiments demonstrate gas breakdown within a single point defect in a 2D photonic crystal at millimeter wave frequencies (43.44 GHz) using only 1.5 W of continuous wave input power. We show that after formation of the plasma within the defect, the transmission of energy through the crystal is decreased by two to four orders of magnitude for gas pressures from 30 to 750 torr. Time domain measurements of the transmitted energy through the device show plasma formation times ranging from 800 ns at 45 torr to 180 ns at 400 torr of argon gas. Electron density of the plasma is 10
¹⁸
m
^-3
at low pressures and up to 10
²⁰
m
^-3
at 750 torr.