The characteristics of confined ablation in laser propulsion

Compared with direct ablation, confined ablation provides an effective wayto obtain a large target momentum and a high coupling coefficient. By usinga transparent glass layer to cover the target surface, the couplingcoefficient is enhanced by an order of magnitude. With the increase of the gapwidth between the target surface and the cover layer, the couplingcoefficient exponentially decreases. It is found that the couplingcoefficient is also related to the thickness of the cover layer.