HELIUM GAS CONTROL METHOD OF POSITIVE COLUMN TYPE HE-CD LASER PIPE AND POSITIVE COLUMN TYPE HE-CD LASER DEVICE

摘要

PROBLEM TO BE SOLVED: To provide the helium gas pressure control method of a positive column type He-Cd laser pipe for accurately and constantly maintaining a helium pressure within an He-Cd laser pipe to a value on optimum laser oscillation conditions and a positive column type He-Cd laser device. ;SOLUTION: The pipe voltage versus laser output characteristics of a laser pipe at an optimum helium gas pressure is grasped in advance, the pipe voltage is set to the position of A, and further a perturbation voltage signal is applied from a pulse generator for perturbation, thus perturbating the pipe voltage as shown in B. The level and direction of the fluctuation of a laser beam output signal P₁ which fluctuates depending on the perturbation are detected by a phase-sensitive detector and an input power to a helium gas tank heater is controlled as the control signal of an output signal P₂ of the phase-sensitive detector, thus controlling the amount of supply to the laser pipe of helium gas.;COPYRIGHT: (C)1997,JPO