Nondestructive single-shot soft x-ray lithography and contact microscopy using a laser-produced plasma source

A toroidal relay optic has been used to overcome the problem of damage caused by debris that has limited previous attempts at soft x-ray lithography and contact microscopy using laser-produced plasma sources. Not only is the specimen preserved, but it is now possible to have a vacuum retaining soft x-ray transparent Si3N4 window as a permanent part of the apparatus, greatly simplifying specimen handling. The exposure times are ˜2 ns. © 1987, Optical Society of America.