PURPOSE: To make preliminary ionization uniform and to obtain a uniform main discharge by arranging a plurality of auxiliary electrodes covered with dielectrics in the dielectrics in contact with the back side of a main electrode comprising plural openings.
CONSTITUTION: A high voltage from a high-voltage power source 1 is applied between first and second main electrodes 2 and 3 of a pulse laser device. A laser medium is excited by a uniform main discharge 8 to emit laser beams in a direction of an optical axis 9. Dielectrics 4 are so arranged that they are in contact with the back side of said main electrode 3. Plural auxiliary electrodes 5 covered with the dielectrics 4 are arranged corresponding to openings 7 of the main electrode 3 to compose an auxiliary electrode group 5A. Between this electrode group 5A and the main electrode 3, a high voltage from an auxiliary power source 6 is applied to generate an auxiliary discharge. Then, auxiliary discharges generated by the auxiliary electrodes 5 make electrons in the vicinity of the main electrode 3 uniform and the uniform main discharge 8 is generated.
INOUE MITSUO
SATO YUKIO
HARUTA TAKEO
NAGAI HARUHIKO
