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State of the art time-to-digital converter

  • quTAG - state of the art time-to-digital converter

The fastest Time-Tagger in the solar system

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  • Specifications
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  • Use cases
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The quTAG is a high-end, easy-to-use time-to-digital converter and time tagging device designed for time correlated single photon counting (TCSPC). It is capable of detecting events with a digital resolution of 1 picosecond and a jitter under 10 ps RMS.
It consists of 4 input channels and allows capturing up to 100 million time tags per second. Its user-adjustable design registers all signals between -3V up to +3 V, like the widely used LVTTL or NIM.
Separate channels for start and external clock are available and easily accessible on the front panel. It connects with a computer via USB, preferably USB 3.0 to transfer the extensive data.
It is delivered with software for Windows and Linux with an easy-to-use graphical user interface. The software includes an analyzing tool for lifetime measurements and correlation functions (HBT measurements).
It can also be integrated in custom software; libraries for Windows and Linux are provided. Examples for LabView and Python are included.

Key Features

  • < 25 ps / < 10 ps timing jitter (FWHM/RMS)
  • 100 MEvents/s max. rate
  • 1 ps digital resolution
  • 4 stop channels, 1 start channel
  • max. 16 stop channels

Timing jitter< 10
< 25
ps RMS
Digital resolution1ps
Number of stop channels4
(max. 16)
Max event rate100
M/s (per device)
M/s (per channel)
Input signalse.g. LVTTL, NIM
everything between -2 V and +3 V
Input connectorsSMA
Connection to PCUSB 3.0
USB 2.0
SoftwareGUI, DLL, LabView, Python, Command line
Windows, Linux
Dimensions44 x 30 x 5cm x cm x cm

All specifications can be found in the datasheet.

Time-Correlated Single Photon Counting (TCSPC)
Fluorescence/Phosphorescence Lifetime Measurements / Imaging (FLT / FLIM)
Fluorescence (Lifetime) Correlation Spectroscopy (FCS / FLCS)
Foerster Resonance Energy Transfer (FRET)
Single Photon Emitter Characterisation
We used the quTAG for two experiments together with the superconducting nanowire single photon detector (SNSPD) from our long-time collaborators at Single Quantum. The results proved the efficiency and speed that we expected as we engineered the quTAG.

Measurement 1: Laser trigger as Start, Single Quantum SNSPD as Stop

We measured a time difference histogram between the trigger pulse from the laser as start and the SQ detector signal as stop.
This is basically the setup for a Fluorescence Lifetime Imaging (FLIM) measurement..

Whole system response function (blue, measured with quTAG): Timing jitter 17.8 ps RMS, 35.9 ps FWHM
For comparison: Detector response function (red, measured with fast oscilloscope): Timing jitter 14.5 ps RMS, 26.1 ps FWHM.


Measurement 2: One SQ Detector as Start, another one as Stop

Here, we measured the time difference histogram between one of the two SQ SNSPDs as Start and the other one as Stop pulse.

Timing jitter of 2 SQ SNSPDs measured with the quTAG (blue): 21.6 ps RMS, 45.6 ps FWHM.