Recently, a team of chemists, mathematicians, physicists and nano-engineers at the University of Twente in the Netherlands developed a device to control the emission of photons with unprecedented precision. This technology could lead to more efficient miniature light sources, sensitive sensors, and stable quantum bits for quantum computing.
The paper, titled “Strongly inhibited spontaneous emission of PbS quantum dots covalently bound to 3D silicon photonic band gap crystals,” is published in the Journal of Physical Chemistry C.
The part of your smartphone that consumes the most energy is the screen. Reducing any unwanted energy that escapes out of the screen increases the durability of our smartphone. Imagine that your smartphone only needs to be charged once a week. However, to increase the efficiency, you need to be able to emit photons in a more controlled manner.
MINT-toolbox
The researchers developed the “MINT-toolbox”: a set of tools from the scientific disciplines of Mathematics, Informatics, Natural Sciences and Technology. In this toolbox, there were advanced chemical tools. The most important were polymer brushes, tiny chemical chains that can hold the photon sources at a certain place.
First author Andreas Schulz explains, “The polymer brushes are grafted in solution from pore-surfaces inside a so-called photonic crystal made from silicon. Quite a tricky experiment. So we were very excited when we saw in separate X-ray imaging studies that the photon sources were sitting at the right positions on top of the brushes.”
By adding nanophotonic tools, the team has demonstrated that excited light sources are inhibited by nearly 50 times. In this situation, a light source remains excited 50 times longer than usual. The spectrum matches very well with the theoretical one calculated with advanced mathematical tools. Second author Marek Kozoň says, “The theory predicts zero light since it pertains to a fictitious infinitely extended crystal. In our real finite crystal, the emitted light is non-zero, but so small it’s a new world record.”
The new results promise a new era for efficient miniature lasers and light sources, for qubits in photonic circuits with strongly reduced perturbations (due to elusive vacuum fluctuations). Willem Vos says, “Our multi-toolbox offers opportunities for completely new applications that profit from strongly stabilized excited states. These are central to photochemistry and could become sensitive chemical nanosensors.”
