© Hector Fellow Academy
2. December 2021
Paper by Martin Wegener published

Two-step absorp­tion enables smaller and more cost-effec­tive 3D laser printers

Lasers in conven­tional laser print­ers for paper print­outs are very small. 3D laser print­ers for 3‑dimensional microstruc­tures and nanos­truc­tures, by contrast, require big and expen­sive laser systems so far. Researchers of Karlsruhe Insti­tute of Technol­ogy (KIT) and the Heidel­berg Univer­sity now use another process for this purpose: Two-step absorp­tion works with inexpen­sive and small, blue laser diodes. As a result, much smaller print­ers can be used. Their work is reported in Nature Photonics.

Currently, complex pulsed laser systems have to be applied, result­ing in big dimen­sions of the laser printer. When using the two-step process, more compact, smaller print­ers can be realized. The first photon trans­fers the molecule to an inter­me­di­ate state. In the second step, a second photon trans­fers the molecule from the inter­me­di­ate state to the desired excited state and starts a chemi­cal reaction. The advan­tage: Contrary to two-photon absorp­tion, the absorp­tion of the two photons must not neces­sar­ily happen at the same time.

To Martin Wegener, the advan­tage is obvious: “It is a big differ­ence between using a femtosec­ond laser as large as a big suitcase for several ten thousand euros or a semicon­duc­tor laser that is as large as a pinhead and costs less than ten euros.” This way, 3D laser nanoprint­ers might become afford­able for many groups.

Congrat­u­la­tions to Martin Wegener!