Influence of geometry variations and defects on the near-field optical properties of pulsed compression gratings

The internal electric field enhancement is critical for the laser induced damage properties of pulse compression gratings (PCG) in high-energy laser systems. Due to complex fabrication processes of PCG such as coating, interference lithography and etching, different kinds of defects, like nodular defects in multilayers and non-uniformities of the grating profiles on PCG surface, cant be practically avoided. From simulation results, we can know that some of these defects have little effect on the spectral response of optical elements, but they may produce huge changes of internal electric fields and thus decrease the damage threshold of PCG. To obtain a better understanding of the dependence of the internal electric field enhancement on these defects and their dimensions, this work is foc used on the near field distributions of defective PCGs using rigorous electric magnetic field (EMF) solvers.