(ORDO NEWS) — Researchers have developed the first nanomaterial in which the “photon avalanche” effect is observed. The development will find many applications – from ultra-high resolution optical microscopy to quantum sensing.
If one photon hits these nanoparticles, then 26 quanta of light will come out of them. For the first time, such parameters of physics were recorded for particles with a size of only 20 nanometers.
Avalanche motion is an example of a non-linear process in which a change in the input signal or excitation results in a very large change in the output signal. To efficiently create nonlinear optical signals, large volumes of matter are usually required, and previously, the “photon avalanche” was only observed in relatively large crystals.
In optics, a photon avalanche is a process in which a crystal absorbs one photon and emits several at once. The effect of a photon avalanche can be observed in specialized lasers, in which the absorption of light quanta induces a cascade of events that ultimately lead to efficient generation of radiation. Special attention of researchers is attracted by the fact that the absorption of one photon leads not only to the emission of a large number of these particles, but also to an amazing property: the emitted photons have higher energy than the absorbed one.
Until now, a photon avalanche has been created only in relatively large crystals consisting of lanthanides. Now researchers have been able to create particles from compounds of these elements measuring only 20 nanometers, in which the movement of a photon avalanche is also possible. The team found that the nonlinear optical response in these nanoparticles is so high that a change in the intensity of the incoming signal by only 10% leads to an increase in the intensity of the output signal by more than 1000%. A single incoming photon is calculated to generate 26 exit particles.
Such properties of new nanoparticles promise them prospects for use as supersensitive sensors, since they will be able to detect the slightest changes in illumination. The introduction of such particles into optical microscopes, according to the authors, will significantly exceed the diffraction limit of modern devices.
An article about the discovery was published in the journal Nature.
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