Superradiant emission from van der Waals laser

The new concept of 2D laser based on superradiant emission opens up completely new possibilities for constructing ultra-thin radiation sources, the wavelength of which can be tuned by the number of layers of 2D semiconductor and boron nitride external electric and magnetic fields.

Conventional laser light is created by amplifying photons in a set of highly reflective mirrors. However, in this process, heating and subsequent thermal vibrations of the mirrors occur, which cause a change in the size of the cavity, limiting the phase of the emitted photons. As a result, this light is spectrally imperfect. In the proposed concept, the super-radiant source does not rely as a conventional laser on a large population of photons in the laser cavity but on the synchronized emission of photons in the optically excited 2D material. Specifically, superradiance arises from the radiant relaxation of excited electron-hole pairs (so-called excitons) in two atomically thin layers of a 2D semiconductor separated by several boron nitride layers. The study was published in the May issue of Advanced Functional Materials (link).