Fabrication of Backlighter Laser Targets via Lithography

Lithographed wire targets have recently been fabricated for use as backlighter targets for experimental campaigns at the OMEGA laser facility. These experiments required targets with 10-m gold wires lithographed onto plastic. A process was developed using lithography to make these targets via sputter coating and liquid solution removal of the resist. One of the challenges overcome in developing this target was depositing the gold so that it would strongly adhere to the plastic. The quality of the lithographed targets was much better than targets made by other methods, such as gluing or thermal techniques. The lithographed targets were straighter, which is important in order to minimize the emission spot size at shot time. The lithographed targets also did not have problems with plastic or glue covering the wires, which can also reduce target emission, another challenge for gluing or thermal techniques. Lithography also allows a large number of similar targets to be made at once and cut out to the individual size needed, and a wide range of complex patterns or designs are possible using this technique.