A light pulse in an optical fiber is like a starter's pistol shot: short, sharp, and unmistakable against the silence. It is exactly such pulses that the new artificial neuron, built on a silicon chip, produces. It is made from a gallium phosphide crystal — a material that can oscillate and transmit light at the same time.

When a weak signal is applied, the device stays silent. But once the signal crosses a threshold, the crystal emits a flash of light, much like a nerve cell responding to stimulation. The intensity of the flash cannot be altered: it is always the same. This is the "all-or-nothing" principle, like a gunshot: either it fires or it doesn't. The researchers confirmed that the neuron can accumulate weak signals and, after firing, remains unresponsive to new stimuli, like a tired runner after a sprint.

Such optical neurons are needed for computers that sit next to sensors — in cameras, robots, smartwatches. They consume very little energy and respond without delay. Moreover, the device is made on the same silicon as conventional chips, so it can be produced in the same factories. This is a step toward machines that think like a brain but speak the language of light.