Parallel plate transmission line laser excitation system

Claim 1

In a laser generator including: an active gaseous medium; an electric excitation line formed by an insulating plate inserted between a first metallic plate and a second metallic plate, an edge of the said plates being formed in the shape of a parabola, the foci as well as the apices of the parabolas being respectively arranged on the same straight line perpendicular to the plane of the plates, the metallic plates being parallel to one another and connected to a voltage source, the first metallic plate having at least one slot separating it into two distinct parts, the common axis of the parabolas forming an angle Alpha greater than zero with the slot; means for maintaining an active gaseous medium in the said slot, comprising a longitudinal blade closing the slot and fixed to the said two parts of the first metallic plate; and means for generating a current wave in the said line, comprising a release circuit for setting up a substantially punctiform discharge between the said metallic plates at the level of the foci of the parabolas; and comprising the improvement wherein: in the immediate vicinity of said slot (6) and on the side of said release circuit (5), said insulating plate (1) as well as said first metallic plate (2) form a projecting part (12) so that a cavity (15) having an axis (13) substantially parallel to the axis (4) of the slot(6) is formed between the insulating plate (1) and said second metallic plate (3); and said cavity (15) contains at least one fluid having a dielectric rigidity whose value is, on the one hand, less than the value of the dielectric rigidity of the insulating material forming said insulating plate (1) and, on the other hand, adjusted in such a way that any over-voltage induced in the electric excitation line at the time of the setting up of a first discharge between between the metallic plates (2, 3) at the level of the foci (F) of the parabolas causes a second discharge between the said metallic plates (2, 3) exclusively through the fluid in the said cavity (15).