Why Single-Photon Detection Matters

What is single-photon detection about?

Single-photon detection may sound like a niche topic from the physics lab. In reality, it describes a capability that is critical for many modern optical technologies: detecting individual particles of light — the smallest measurable unit of light . While ordinary cameras or sensors need many photons at once to produce a signal, single-photon detectors operate exactly where light is extremely weak — at the very limit of what is physically measurable .

What does single-photon detection mean technically?

In everyday life, light appears continuous. Physically, however, it consists of individual photons. Single-photon detection means a detector is able to reliably detect these individual light quanta . This is technically demanding, because the weaker the signal, the more important it becomes to distinguish real light signals from noise . This is exactly where single-photon detectors come in: they make measurable what is already too faint for conventional sensors.

Is there a simple analogy?

A useful analogy is a single raindrop on a roof. Most sensors only work reliably when many drops fall at once — when there is clearly audible rain. Single-photon detection, by contrast, means perceiving the very first single drop , even though near-total silence surrounds it. It is not about producing more light, but about being able to extract reliable information from minimal amounts of light .

Why does it matter?

Many photonic applications operate with extremely small amounts of light. In quantum communication, for instance, single photons carry information . In sensing, their precise detection determines whether weak signals become visible at all . And in time-critical measurements, it matters not only that a photon is detected, but also when — often with very high temporal precision. Single-photon detection is therefore a key enabling technology : it extends the limits of what can be measured, transmitted, and evaluated with light.

Where is single-photon detection used?

Today, single-photon detection is used in several important scenarios: in quantum research and quantum communication , in LiDAR systems for three-dimensional environment sensing, in imaging, in spectroscopy, and going forward also in medical technology. It is especially relevant whenever little light is available, long ranges are required, or the highest precision matters .

How does GeQD see this technology?

From our perspective, single-photon detection is a key technology for the next generation of optical systems . This is exactly where GeQD comes in: we are working to make individual photons reliably detectable in the visible to short-wave infrared range . Our goal is therefore to combine high sensitivity, precise time resolution, and practical integrability .

What is GeQD's ambition?

Our ambition combines technical feasibility with scientific performance. Single-photon detection cannot only work in highly specialised labs. It must also be compact, robust, and ultimately scalable , so that an impressive physical measurement method becomes a usable technology. We see the potential of GeQD precisely in this bridge between scientific performance and technical feasibility . For us, single-photon detection is therefore not just a research field, but the foundation for applications where classical detectors reach their limits — for example in quantum technologies, LiDAR, and other photonic sensing. Our ambition is to advance this technology so that it not only opens up new measurement possibilities, but also finds its way into real systems.

Universität Stuttgart – Institut für Halbleitertechnik

Contact

Pfaffenwaldring 47

70569 Stuttgart, Deutschland

Tel: +49 711 68560896

info@geqd.de

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