Abstract: A gas laser having preionization means which comprises an elongated glass tube extending beside the glow discharge volume for the length of the laser cavity, there being a central conductor inside the tube and a conductive strip or spaced strips bonded to the outside of the tube. The inner wire and outer strip are connected respectively to the same high voltage pulse leads which provide the main laser discharge. Ultraviolet radiation from the conductive strips on the tube preionizes the laser gas and creates a stable uniform laser electric discharge.

Abstract: A laser having its lasing medium located within two or more portions of a single optical cavity. The lasing media within different portions of a single optical cavity are excited in sequence to obtain lasing actin over an extended temporal period.

Abstract: A laser beam is passed between a pair of electrodes, the switching of the beam being accomplished by generating an arc between the electrodes whereby metal vapor is ablated therefrom. The metal vapor acts to either refract or totally block the beam, in either case cutting off the laser output.