In a new Cluster collaboration, first author Young Scientist Vincent Hahn reviews three promising alternatives to Two-Photon Absorption: Upconversion Luminescence, Two-Step Absorption and Triplet–Triplet Annihilation. All of those emerging excitation processes the authors termed “(1+1)-Photon Absorption” allow the use of continuous-wave lasers at much lower peak laser powers and at much lower cost than those typical for Two-Photon Absorption. The paper also sheds light on current challenges and opportunities in 3D Laser Printing based on (1+1)-Photon Absorption as well as future perspectives.
