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Advancements in SWIR Laser Technology with Colloidal Quantum Dots

In the realm of laser technologies, current methods for the extended shortwave infrared (SWIR) spectrum are often hindered by the high costs and complexity of the materials used, which pose challenges to their scalability and affordability. Researchers at ICFO, led by ICREA Professor Gerasimos Konstantatos, have made significant strides in addressing these limitations. Their innovative approach, which involves colloidal quantum dots, was detailed in a recent article published in Advanced Materials. The team successfully achieved coherent light emission in the extended SWIR range utilizing large colloidal quantum dots derived from lead sulfide (PbS).

This breakthrough offers a viable solution to the existing challenges while ensuring compatibility with silicon complementary metal-oxide-semiconductor (CMOS) platforms, which are widely used in the design of integrated circuit chips. This compatibility is crucial for seamless on-chip integration.

The PbS colloidal quantum dots developed by the team stand out as the first semiconductor lasing materials capable of covering an extensive wavelength spectrum. Impressively, these advancements were accomplished without modifying the chemical structure of the quantum dots. This discovery paves the way for more efficient and compact laser systems based on colloidal quantum dots.

Additionally, in a noteworthy first, the researchers demonstrated lasing in PbS quantum dots through nanosecond excitation. This method offers a substantial advantage by eliminating the need for large, expensive femtosecond laser amplifiers. The use of larger quantum dots increases the dots’ absorption cross-section significantly—by tenfold—thereby reducing the optical gain threshold, which is the critical point where efficient laser light emission occurs.

The capacity to create affordable and scalable infrared lasers within the extended SWIR range removes significant obstacles faced by numerous industries. This innovation holds the promise of revolutionizing applications in hazardous gas detection, eye-safe LIDAR systems, advanced photonic integrated circuits, and imaging used within the SWIR biological window. Sectors reliant on LIDAR technology, gas sensing, and biomedical applications are poised to gain substantially from this cost-effective and integrable solution. Furthermore, the findings support the advancement of silicon-compatible photonic integrated circuits, fostering further miniaturization and broader adoption of these technologies.

“Our work represents a paradigm shift in infrared laser technology,” stated Prof. Gerasimos Konstantatos. “For the first time, we’ve achieved lasing in the extended SWIR range with solution-processed materials at room temperature, opening up avenues for practical applications and the creation of more accessible technologies.”

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