Precision laser beam shaping apertures

The important role played by beam shaping (apodizing) apertures in the successful operation of high-power laser systems is a acknowledged fact.1-4 In systems such as those being developed for laser fusion experiments at LLL, the optimum whole beam spatial profile represents a sensitive tradeoff between conflicting requirements: (1) efficient energy extraction from the laser and (2) propagation through the amplifier chain with minimal beam breakup from linear (diffraction) and nonlinear effects. An additional constraint on the choice of whole beam profile is imposed by the specifications on the focal (far-field) distribution of the beam occurring at, or near, small laser fusion targets. In order to achieve a balance among these requirements, it is mandatory to utilize optical elements that can exercise precise control of the whole beam spatial intensity profile of the laser.