Original title: Micro-transfer Printed Blue InGaN Lasers on Silicon Nitride Photonic Integrated Circuits
Konstantinos Akritidis, Krzysztof Gibasiewicz, Han Wang, Iryna Levchenko +7 · September 2026
Computer chips that use light instead of electricity need built-in light sources to work. Silicon nitride makes great circuits for visible light, but adding blue gallium nitride lasers to these chips has been a major bottleneck. Older methods are either too slow or risk breaking delicate parts across large surfaces. To solve this, researchers used micro-transfer printing to pick up pretested microscopic lasers and stamp them onto the chip. Gallium nitride is chemically tough, so releasing thin lasers usually ruins the material. The team overcame this by using a heavily doped sacrificial layer and an optimized etching process to release smooth thin-film lasers from their original base. They stamped the lasers onto the chip and aligned them directly to fork-shaped silicon nitride light collectors. The finished devices produced blue laser light at 455 nm and handled high current densities exceeding 20 kA/cm^2.
Imagine you have a delicate flower pot glued onto a large stone. You want to move just the pot to a new stand, but the glue is extremely strong. Normally you might cut the stone or pry it off, risking damage. Here, the scientists use a special layer under the pot that dissolves when they apply a gentle electric current, releasing the pot cleanly. In this paper, the flower pot is the laser, the stone is the original substrate, and the electric current is the electrochemical etching that removes the sacrificial layer.
Integrated photonics uses light instead of electrons to process information. Until now, blue lasers—needed for displays, medical devices, and quantum experiments—could not be easily placed on silicon chips. This work shows a way to print them there, opening up smaller, faster, and more versatile optical systems.
The method is only demonstrated for blue lasers; other wavelengths or device types may require different etching conditions. Long-term reliability and large-scale manufacturing are not yet established. The sacrificial etching process, while optimized, still depends on precise doping levels and may not work for all GaN structures.
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Micro-transfer Printed Blue InGaN Lasers on Silicon Nitride Photonic Integrated Circuits — Konstantinos Akritidis, Krzysztof Gibasiewicz, Han Wang et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.