Design techniques and measured performance for a uniformly pumped 4-cm diam rod amplifier

Laser amplifiers designed for use in laser fusion systems must necessarily meet stringent gain uniformity requirements in order to avoid impairing the laser beam apodization. Since the intensity profile of the laser beam directly affects the illumination uniformity (and hence the implosion symmetries) of laser fusion targets, it is essential that the individual laser amplifiers in each amplifier chain have high gain and highly uniform gain distributions. For large aperture glass laser rod amplifiers, this is difficult to achieve since the pumping radiation from the flashlamps must pass through the outer portions of the laser rod before the axis can be pumped.