A photodissociation iodine laser amplifier series is developed and the characteristic output is examined. The amplifier series consists of an oscillator, a pre-amplifier, and a main-amplifier.
In the pumping reflectors of the oscillator and the preamplifier, two parallel flash lamps placed at the foci of a double ellipse are used. The main- amplifier consists of two sections and in a section four flash lamps system is employed, each flash lamp being placed at the foci of the four-fold ellipse cavity.
As the active medium of the laser,$i-C_3F_7I$ is used and the argon gas as the buffer gas in the amplifier.
In order to run the amplifier series effectively, the beam quality of the oscillator and the pre-amplifier are examined in detail. The beam divergence is found to be 4.0 mradian, which is closely in the theoretical value, 3.5 mradian. The effect of the shockwave produced during optical pumping is examined. This effect is, however, avoided by giving 3-4μsec delay time between the amplifier pumping and the oscillator pumping. When that delay time is introduced, the output pulse is found to produce accurate Fresnel diffraction pattern.
To examine the characteristic output of the amplifier series, the laser oscillator is made to oscillate with $TEM_{\circ\circ}$-mode, and the output pulse is fed to the preamplifier and then the main-amplifier. The gas pressure of the active medium ($i-C_3F_7FI$) of the oscillator and the pre-amplifier are both fixed to 100 torr and that constant pressure the main-amplifier output energy is measured and its dependence on the fill gas pressure is measured. And it is found that the maximal output energy from the main amplifier is 3.5J, when the pressure of $i-C_3F_7I$ is 40 torr. Therefore the energy gain $G_E$ of the pre-amplifier and the main amplifier are 11.5, and 13.0, respectively. In this case the electrical efficiency is worked out to be as high as 0.16%.
The research on the power output depending on the partial pressure of argon gas, the buffer gas, is made, but the dependence is found not significant. The pulse forms of the oscillator output and the main-amplifier output are found to be 150 nsec, and 80 nsec, respectively. This measurement proves that pulse is sharpened in the amplifiers. The maximum power output of the entire system is thus determined to be 45 MW.
