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!