Sensitive Photoresists for Rapid Multiphoton 3D Laser Micro- and Nanoprinting

Driven by recent advances in rapid multiphoton single-focus 3D laser nanoprinting, multifocus variants thereof, and projection-based multiphoton 3D laser nanoprinting, the necessary average total laser powers from femtosecond laser oscillators or even from amplified femtosecond laser systems have exceeded the Watt level. Aiming at ever faster 3D printing, there exist two options: Using yet more powerful lasers or searching for more sensitive photoresists allowing for higher speeds at comparable or lower power levels. Here, altogether more than 70 different photoresists from the literature and a few new candidates are reviewed with regard to effective multiphoton sensitivity. A dimensionless sensitivity figure-of-merit allows to directly compare data taken under sometimes vastly different conditions.