Energy loss in focal spot by CO₂ laser mitigation treatment

An experimental setup referring to the optical element configuration of National Ignition Facility was built. The energy loss from mitigation cone by CO2 laser was tested. The results showed that the loss ratio had a linear correlation with the density of mitigation cone while the density was low. The energy would lose faster with the increase of density if the mitigation cone was larger. Density of mitigation cone must be small than 2 cm-2 to ensure the loss ratio less than 3%.