A time tagger is a measurement device that records the exact arrival time of incoming electrical signals and stores it as a digital timestamp. Think of it as an extremely precise stopwatch: every time a detector registers a photon or a laser pulse arrives, the time tagger notes the time – down to the picosecond.
These timestamps answer key questions: Did two photons arrive at the same time? How long did a light pulse travel? How fast does fluorescence decay? These questions are at the core of quantum communication, microscopy and LiDAR.
The duo 4CH Time Tagger from duotec records such timestamps on four channels simultaneously, with a resolution of 1 picosecond. For comparison: in one picosecond, light travels just 0.3 millimeters.
How the duo 4CH Time Tagger works
The duo 4CH Time Tagger works in three steps:
Detect the signal. Signals from detectors or pulse sources arrive at four SMA inputs. An adjustable trigger threshold (0 to 2.5 V) defines which voltage counts as an event.
Set the timestamp. For every detected signal, the duo 4CH Time Tagger sets a timestamp with 1 ps resolution. Timestamps are written to internal memory at up to 47.6 million events per second (all channels combined).
Analyze the data. Data is transferred to a PC via USB. The included API for Windows and Linux reads data out and prepares it for analysis.
To keep all timestamps on the same time base, the duo 4CH Time Tagger uses an external 10 MHz clock, an internal oscillator or integrated GNSS synchronization.
What sets the duo 4CH Time Tagger apart
1. Picosecond precision.
1 ps resolution and 30 ps RMS (72 ps FWHM) timing jitter. The duo 4CH Time Tagger separates events that are only fractions of a nanosecond apart – the basis for clean coincidence measurements and precise time of flight.
2. Compact, not rack-sized.
106 × 55 × 26 mm. The duo 4CH Time Tagger sits right next to the experiment, fits into mobile systems and saves lab space. Short cable runs to the detector included.
3. Synchronized across distances.
Integrated GNSS synchronization puts separate stations on a common time base – such as transmitter and receiver of a QKD link – without additional reference hardware. Alternatively: external 10 MHz clock or internal oscillator.
4. Ready to use.
Four internally terminated SMA inputs, USB connection and included software for Windows and Linux. Connect the detector, set the threshold, measure.
5. From instrument to OEM solution.
duotec designs the duo 4CH Time Tagger as a platform. Interfaces, signal levels and form factor can be adapted to customer systems – from feasibility to series production, with a European supply chain. Designed and manufactured in Germany.
Typical applications forTime Tagger:
Quantum key distribution (QKD)
In quantum key distribution, a tap-proof key is generated from single photons. Transmitter and receiver must know exactly when each photon arrived. The duo 4CH Time Tagger delivers these timestamps – and synchronizes both stations via GNSS, even over long distances.
Fluorescence lifetime imaging microscopy (FLIM)
FLIM measures how long a molecule glows after excitation, revealing cell states and molecular environments. The duo 4CH Time Tagger records the arrival time of each photon relative to the laser pulse (TCSPC principle) and provides the basis for lifetime histograms.
Single photon counting and coincidence measurement
Detector characterization, quantum optics experiments or correlation measurements: the duo 4CH Time Tagger counts photon events on four channels and reveals which of them occur simultaneously.
Download now our Product Overview
Download our Time Tagger product overview for more information on this break through innovation.
