But adapting the two-laser approach to curing photoresists wasn't easy. when our group at KIT started to look into the possibility in 2008, there were no photoresists that had been specific cally developed to support the approach. One complication we encountered early on was that photoinitiators are designed to be efficient; after they're hit by photons, they react in almost no time at all, too fast for a second laser beam to de-excite the molecule and stop the polymerization reaction. It took about a year of research and some trial and error, but we eventually found a photoinitiator- a dye molecule that had been used only sparingly for lithography up until that point-that would do the job.