OPTICAL APPARATUS FOR PLASMA

摘要

PURPOSE: An optical apparatus for plasma is provided to measure the spatial distribution of plasma emitted light by regulating the distance between a light receiving lens and a pin-hole. CONSTITUTION: A light receiving lens(110) receives optical emission spectrum from plasma. A first aperture is arranged between the light receiving lens and the plasma to block out-focused light. A second aperture is arranged between the light receiving lens and the phase forming region of the light receiving lens to block in-focused light. A pin-hole is arranged in the phase forming region of the light receiving lens to limit the depth of focus with respect to a target region.