Phys.org December 10, 2024
Currently, the spectral coverage of solution-processed lasers extends from visible up to telecom wavelengths in the short-wave infrared. Using lead sulphide based colloidal quantum dots researchers in Spain demonstrated the optical gain in the extended SWIR from 1600 nm to 2500 nm which has many applications such as in LIDAR, biological imaging and environmental monitoring. Using the carbon quantum dots (CQDs) in distributed feedback laser cavities, lasing with emission was tuned between 2150 nm and 2500 nm is reported. Due to the increased absorption cross-section of larger CQDs, the optical gain threshold was reduced by a factor of 36 compared to smaller-sized CQDs, reaching an amplified spontaneous emission threshold down to 42 µJ cm−2. Gain and lasing under nanosecond excitation were also demonstrated. According to the researchers their work paves the way for realizing compact and practical CQD infrared lasers and potentially toward electrically driven laser diodes… read more. TECHNICAL ARTICLE