Sensitive multi-photon photoresists: Overview and recent advances

Recently, the necessary average total laser power for rapid multi-photon multi-focus applications has exceeded the Watt level. To enable even faster 3D printing, we have developed new sensitive photoresists by adding co-initiators to commonly used standard systems. We yet exceed these advances in sensitivity using a novel photoresist system based on a modified benzylidene ketone photoinitiator, making it a very attractive system for advanced rapid 3D laser nanoprinting. To compare our original results to more than 70 different published systems from the literature, we define a photoresist-sensitivity figure-of-merit, enabling a fair comparison to measurements taken under vastly different conditions.