Photon antibunching is a quantum optical phenomenon where photons are emitted one at a time rather than in groups or bunches. This behavior cannot be explained by classical physics and provides direct evidence that light is made of discrete particles — photons.
Key Points:
- In classical light sources (like a lamp), photons may arrive randomly or in clusters.
- In antibunching, there is a measurable time gap between detected photons, indicating single-photon emission.
- This effect is observed in systems like single atoms, quantum dots, or trapped ions, which can only emit one photon before needing to be re-excited.
Why It Matters:
- It confirms the quantized nature of light — a cornerstone of quantum electrodynamics.
- It is essential for technologies requiring single-photon sources, such as:
- Quantum cryptography
- Quantum computing
- Quantum metrology
Photon antibunching is a striking demonstration that light is not just a wave — it comes in indivisible units, reshaping our understanding of light-matter interactions.