Geiger-mode operation
In Geiger-mode operation, an InGaAs avalanche photodiode (APD) is operated above its breakdown voltage. In this state, the absorption of a single photon is sufficient to trigger avalanche multiplication and generate a measurable signal.
Detection occurs on a single-photon basis, enabling maximum sensitivity even at very low light levels. A quenching circuit is used to control the operation, reliably terminating the avalanche after the event and resetting the detector for the next photon measurement.
Characteristics
- Operation above the breakdown voltage (Vbr)
- Photon → electron avalanche → measurable signal
- Requires active or passive quenching circuit
- Very high detection probability with simultaneously low dark noise
Typical applications
- LIDAR for autonomous vehicles and precise distance measurement
- 3D imaging & time-of-flight cameras
- Quantum technologies such as quantum communication & cryptography
- Biophotonics for sensitive measurements up to single-molecule detection
- Astronomy for the detection of faint, distant light sources
Advantages of Geiger mode
- Maximum sensitivit – detection of single photons
- Extremely fast response times in the picosecond range
- Wide range of applications, even with extremely weak light signals
- Reliability through state-of-the-art quenching and noise suppression technologies