Emergent gain materials for active photonics (Vol. 48 No. 1)

Example of an optical waveguide containing colloidal quantum dots. When the nanostructures are optically pumped the waveguide propagates and confines the photoluminescence. Above a certain threshold light is amplified

Nowadays semiconductor nanostructures developed by colloidal methods have emerged as an alternative to the classical III-V semiconductors and rare earth technologies to provide active functionalities in photonic devices. Their outstanding optical properties include high absorption cross section, high quantum yield of emission at room temperature, or the capability of tuning the band-gap with the size/base material. As a consequence, these materials have been successfully applied in several fields, such as photodetection, amplification, generation of light or sensing. For these purposes their solution process nature provides a cheap fabrication, and an easy incorporation on a broad range of substrates and photonic structures. This review summarizes the great effort undertaken by the scientific community to construct active photonic devices based on semiconductors fabricated by chemical methods. The work compares the performances demonstrated by semiconductor nanocrystals (colloidal quantum dots, quantum rods and quantum wells) with those provided by organometal halide perovskites, and describes their appropriate integration into photonic architectures (waveguides and cavities) to achieve stimulated emission.

I. Suárez Alvarez, Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites, Eur. Phys. J. Appl. Phys. 75, 30001 (2016)