Cost-effective lasers for extended SWIR applications
Using large lead sulfide quantum dots, scientists have developed the first semiconductor lasing material that can emit coherent light across the extended short-wave infrared spectrum
Researchers have reported the first colloidal quantum dot (CQD)-based laser capable of operating across the entire extended short-wave infrared (SWIR) spectrum, representing a significant step towards more affordable and scalable solutions for applications ranging from environmental monitoring to biomedical imaging.
Current laser technologies for the extended SWIR spectral range rely on expensive and complex materials, limiting their scalability and affordability. To address these challenges, scientists from the Institute of Photonic Sciences (ICFO) in Barcelona and the Catalan Institution for Research and Advanced Studies (ICREA), have presented a novel approach based on colloidal quantum dots, published in the journal Advanced Materials. The team managed to emit coherent light (a necessary condition to create lasers) in the extended SWIR range with large colloidal quantum dots made of lead sulfide (PbS). They add that their solution maintains compatibility with silicon CMOS platforms for on-chip integration.
According to the researchers, their PbS colloidal quantum dots are the first semiconductor lasing material to cover such a broad wavelength range, and they accomplished this without altering the dots’ chemical composition. These results could pave the way towards the realisation of more practical and compact colloidal quantum dot lasers.
Furthermore, the team report that they observed lasing – for the first time in PbS quantum dots – with nanosecond excitation, replacing the need for bulky and costly femtosecond laser amplifiers. This was achieved by employing larger quantum dots, increasing the absorption cross-section of the dots tenfold, leading to a dramatic reduction in the optical gain threshold – the point at which the laser light emission becomes an efficient process.
The ability to produce low-cost, scalable infrared lasers in the extended SWIR range addresses critical bottlenecks in various technologies. This innovation has transformative potential for diverse applications, including hazardous gas detection, eye-safe LiDAR systems, advanced PICs, and imaging within the SWIR biological window. Industries relying on LiDAR systems, gas sensing, and biomedicine could benefit from such a cost-effective and integrable solution. Moreover, the scientists say this breakthrough supports the transition to silicon-compatible PICs, enabling greater miniaturisation and widespread adoption.
“Our work represents a paradigm shift in infrared laser technology,” said Gerasimos Konstantatos, professor at ICREA, who led the work. “For the first time, we’ve achieved lasing in the extended SWIR range with solution-processed materials at room temperature, paving the way for practical applications and the development of more accessible technologies.”
Image credit: ICFO
