#  Tunable Ring Laser Chips Broaden Mid-Infrared Wavelength Control 

 





July 13, 2025

 

 

Tunable semiconductor lasers are vital for applications ranging from high-speed telecommunications to gas sensing and medical diagnostics, but existing devices face trade-offs in tuning range, accuracy, and complexity. Theodore P. Letsou, Johannes Fuchsberger, and colleagues have now demonstrated a monolithic mid-infrared ring-array laser chip that provides smooth, wide-range tuning without moving parts by integrating multiple ring resonators of varied sizes onto a single waveguide-based platform. Published in *Optica*, their hybrid quantum-cascade ring laser generates single-mode emission at selectable wavelengths within the 8 µm band, offering robust unidirectional operation, facile fabrication, and scalable performance. This compact tunable laser chip could pave the way for versatile, cost-effective systems in sensing, spectroscopy, and beyond.

See the publication here in [Optica](https://opg.optica.org/optica/fulltext.cfm?uri=optica-12-7-985&id=574056###) and the press release from [Harvard SEAS](https://seas.harvard.edu/news/2025/07/tunable-laser-light).

 ![Artistic rendering of tunable ring laser](/sites/g/files/omnuum6306/files/2025-07/TINYRINGS13_hr_0.png)

 

Image credit: Joshua Mornhinweg



 

 

 



 

 

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