A radio frequency (RF) excited laser assembly includes a pair of opposed electrodes defining an inter-electrode gap and a conductive termination bridge in electrical contact with both electrodes. The termination bridge mechanically supports and positions the electrodes relative to each other and provides a termination impedance for an RF voltage applied to the electrodes. A conical spiral inductor includes one or more metals windings, and one or more concentric terminals, such that the conical spiral inductor defines an inter-winding spacing sufficient to mitigate ionization of a gas medium between windings. A radio frequency (RF) feed-through assembly configured to apply an RF voltage to a pair of opposing electrodes such that a conductor is isolated from a metal sleeve position around the conductor by ion sheath discharge barrier.