Enhanced absorption of intense short-pulse laser light by subwavelength nanolayered target

Abstract

Two-dimensional particle-in-cell simulation shows that a target with subwavelength nanolayered front can reduce the reflection and increase the absorption of the energy of an intense short laser pulse. The electrons within the skin depth on the surfaces of the nanolayers are accelerated by J×B heating to relativistic velocities and ejected into the narrow vacuum spaces between the layers. They then propagate forward with most of the absorbed laser energy along the surfaces of the layers. Conversion of the laser energy into electron energy can be enhanced by optimizing the vacuum spacing between the nanolayers since the phase structure of the laser field in the target is modified. The effects of the layer width, length, and spacing on the energy conversion efficiency are investigated.