TCSPC and Time Tagging Electronics

PicoHarp 300

Stand-alone TCSPC Module with USB Interface

  • Ships within 2 weeks
  • Two identical synchronized but independent input channels
  • 65 536 histogram time bins, minimum width 4 ps
  • Count rate up to 10 million counts/sec
  • Multi-stop capability for efficiency at low repetition rates
  • Adjustable input delay for sync channel with 4 ps resolution
  • Histogrammer measurement range from 260 ns to 33 µs (depending on resolution)
  • Multichannel routing capability
  • External synchronization signals for (fluorescence lifetime) imaging or other control events
  • Optional: Time tagging with sustained count rates up to 5 Mcps
  • Optional: On-line Fluorescence Correlation Spectroscopy (FCS)
  • Optional: Drivers and demo code for custom programming

PicoHarp 330 passes the crown to its successor, PicoHarp 330

More than 1700 units of the PicoHarp 300 have been delivered to customers around the world since its first release in 2004. After almost 20 years the PicoHarp 300 has got a successor: the PicoHarp 330. Please contact us if you are interested.

PicoQuant's 5 year limited warranty for selected product typesThe PicoHarp 300 is a high-end, easy to use, plug and play Time-Correlated Single Photon Counting (TCSPC) system. It is connected to a PC through a USB 2.0 interface. The high quality and reliability of the PicoHarp 300 is expressed by a unique 5-year limited warranty.

Independent channels, 4 ps resolution

A special design approach provides identical and synchronized but independent input channels. They can be used as detector inputs for coincidence correlation experiments or as a pair of start and stop inputs for TCSPC. It allows a forward start-stop operation even at full repetition rate of mode locked lasers with stable repetition rate up to 84 MHz. Experiments with low repetition rate benefit from the PicoHarp's multi-stop capability. The design allows high measurement rates up to 10 million counts/sec and provides a highly stable, crystal calibrated time resolution of 4 ps. The instrument's timing resolution is well matched to even the fastest detectors currently available: the SPAD detectors of the PDM series or micro-channel plate Photomultiplier Tubes (MCP). Both input channels are equipped with Constant Fraction Discriminators (CFD), sensitive on the falling edge.

Adjustable delay in sync channel

The sync channel of the PicoHarp 300 even has an internal adjustable delay with ±100 ns range at 4 ps resolution. This unique feature eliminates the need for specially adapted cable lengths or cable delays for different experimental set-ups.

Operation as time tagger

PicoHarp 300 - Screen shot of the online correlatorA Time-tagged mode for recording of individual photon events with their arrival time on both channels is available as an option, allowing the most sophisticated offline analysis of the photon dynamics. TTTR data can be correlated in real-time for monitoring of FCS experiments at count rates up to 500 000 counts/sec. External marker signals can be used to synchronize the device with other hardware such as scanners, e.g., for Fluorescence Lifetime Imaging (FLIM). In TTTR mode, the PicoHarp 300 can also be used as a generic event timer, e.g., for Satellite Laser Ranging (SLR).

Multichannel routing

As accessories external routers such as the PHR 800 for connection of up to four detectors are available. Each router channel includes an internal adjustable delay with ±8 ns range at 4 ps resolution to tune for relative delays. External hardware such as monochromators can be controlled via CAN or serial bus (currently supported: Sciencetech 9030, Sciencetech 9055, Acton Research SP-2155 and Acton Research SP-275).

Measurement channels
Discrimination Constant Fraction Discriminator (CFD) in both channels, software adjustable
Input voltage range 0 to -800 mV, optimum: -200 mV to -400 mV
Trigger point falling edge
Trigger pulse width 0.5 ns to 30 ns
Trigger pulse rise/fall time 2 ns max.
Time to Digital Converter (TDC)
Minimum time bin width 4 ps
Timing precision* < 12 ps rms
Timing precision / √2* < 8.5 ps rms
Adjustable delay range for sync channel  ± 100 ns, resolution 4 ps
Full scale range - histogram mode 260 ns to 33 μs (depending on chosen resolution: 4, 8, 16, ..., 512 ps)
Full scale range - time-tagged mode infinite
Maximum count rate 10×106 counts/sec
Maximum sync rate 84 MHz
Dead time < 95 ns
Differential non-linearity < 5 % peak, < 1 % rms
Count depth 16 bit
Maximum number of time bins 65 536
Acquisition time 1 ms to 100 hours
TTTR engine
T2 mode resolution 4 ps
T3 mode resolution 4, 8, 16, ..., 512 ps
FiFo buffer depth (records) 262 144
Sustained throughput** typ. 5×106 events/sec
PC interface USB 2.0 high speed
PC requirements min. 1 GHz CPU clock, 512 MB memory
Operating system WindowsTM 7 / 8  (8.1) / 10
Power consumption 25 W at 100 to 240 VAC

* In order to determine the timing precision it is necessary to repeatedly measure a time difference and to calculate the standard deviation (rms error) of these measurements. This is done by splitting an electrical signal from a pulse generator and feeding the two signals each to a separate input channel. The differences of the measured pulse arrival times are calculated along with the corresponding standard deviation. This latter value is the rms jitter which we use to specify the timing precision. However, calculating such a time difference requires two time measurements. Therefore, following from error propagation laws, the single channel rms error is obtained by dividing the previously calculated standard deviation by √2. We also specify this single channel rms error here for comparison with other products.

** Sustained throughput depends on configuration and performance of host PC.

All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice.

Easy to use software and custom programming

PicoHarp 300 - Screen shot of the operation softwareThe PicoHarp 300 software for Windows provides functions such as the setting of measurement parameters, display of results, loading and saving of measurement parameters and measurement curves. Important measurement characteristics such as count rate, count maximum, position and peak width are displayed continuously. A comprehensive online help function shortens the users' learning curve. A library for custom programming, e.g., with LabVIEW is also available as an option. Software upgrades for extended functionality will be available with further product development.

Measurement data from the PicoHarp 300 can be analyzed by different software packages. For multi-exponential reconvolution the EasyTau 2 software is an ideal tool. For the analysis of TTTR data (e.g., FLIM, FCS, FLCS, FRET, BIFL, etc.) the SymPhoTime 64 software suite is the tool of choice. Analysis of photon correlations is best performed with the QuCoa software package.

Operation and software features (current version:

The PicoHarp 300 can be used in various operation modes:

Integration mode

Measurement of the accumulated events as a function of time, manually started, stopped manually or upon overflow or expiration of a chosen collection time or upon reaching of a defined number of counts. 512 curves with up to 65 536 time channels.

Oscilloscope mode

Repetitive measurement and on-line display, very useful for optical alignment. Flicker free histogram display updates and large rate meters for work in the distance.

Time-Resolved Emission Spectra (TRES)

An optional hardware and software add-on allows to control a monochromator from within the PicoHarp software, allowing automated measurement of Time-Resolved Emission Spectra. This mode drives a monochromator via a stepper motor for collection of spectrally resolved lifetime histograms. Data is collected as in standard Integration Mode and saved in different blocks of memory for each wavelength. Four different monochromator types are currently supported: Sciencetech 9030, Sciencetech 9055, Acton Research SP-2155 and Acton Research SP-275.

Time-Tagged Time-Resolved mode(s) (TTTR)

PicoHarp 300 - Screen shot of the online correlatorThe optional TTTR mode allows a continuous recording of events without onboard histogramming straight to disk. Together with the channel number the arrival time of each event pair with respect to the beginning of the experiment is recorded for ultimate flexibility in offline data analysis, e.g., in single molecule detection and Burst Integrated Fluorescence Lifetime (BIFL) measurement as well as time-resolved FCS or coincidence correlation spectroscopy ("antibunching"). Fast transfer and a large FIFO buffer allow huge count rates without any loss of data. Up to four different external synchronization signals ("markers") can be fed into the data stream and allow to synchronize the data acquisition with external hardware such as scanners for Fluorescence Lifetime Imaging (FLIM).

A real-time correlator is included in the TTTR mode which can be extremely useful in setting up and monitoring of FCS experiments.

Software overview

The PicoHarp 300 software allows the control of all measurement parameters provided by the PicoHarp 300 module. Both input triggers are programmable for a variety of signal types. All functions of the system are controlled by a software interface for WindowsXP/Vista/7 or 8. The software provides functions such as the setting of measurement parameters, display of measurement results, loading and saving of measurement parameters and measurement curves. Important measurement characteristics such as count rate, count maximum and position, and histogram width (FWHM) are displayed continuously. An indicator for critical measurement conditions such as pile-up or incorrect divider settings helps to avoid measurement errors.A comprehensive online help function shortens the user's learning curve. Software upgrades for extended functionality will be available with further product development.

The PicoHarp 300 also comes with a programming library for LinuxA library (DLL) for custom Windows program development is available as an option and allows to build your own applications, e.g., in LabVIEW, Matlab, C++, Python or Delphi. Demo code is provided for an easy start. A Linux version is also available for Linux versions 3.0 and higher. The libraries are API compatible, so that applications can easily be ported between the platforms.

The PicoHarp 300 permits the recording of sub-nanosecond fluorescence lifetimes, extendable to < 10 ps with reconvolution. For multi-exponential reconvolution the EasyTau 2software is an ideal tool. PicoHarp data can be directly exported via the clipboard.

PicoHarp 300 - Screen shot of the operation software

Current software and Developer's Library version:

The latest software version is a bug fix release. Highlights of the last major release (version include an internal adjustable delay in the sync channel to replace adjustable cable delays (4 ps resolution, ±100 ns range) and an adjustable delay in all PHR 800 router channels to tune for relative delays (4 ps resolution, ±8 ns range). That software release also include ASCII export and a new future proof file format, unified with that of SymPhoTime 64.

The optional Time-Tagged Time-Resolved (TTTR) mode allows the recording of individual count events directly to hard disk or computer memory. The timing of each photon is captured as an event record without any early data reduction (such as on-board forming of histograms). This mode is particularly interesting where the dynamics in a fluorescence process are to be investigated in depth. The availability of the full timing information permits photon burst identification, which is of great value e.g. for Single Molecule Spectroscopy (SMS) in a liquid flow. Other typical applications are Fluorescence Correlation Spectroscopy (FCS) and Burst Integrated Fluorescence Lifetime (BIFL) measurements. Together with an appropriate scan controller, TTTR mode is also suitable for ultra fast Fluorescence Lifetime Imaging (FLIM) with unlimited image size. Applications beyond fluorescence spectroscopy are e.g. in quantum optics and related basic rearch.The PicoHarp 300 actually supports two different Time-Tagging modes, T2 and T3 mode. They differ slightly in their use of the input channels and by using the suitable mode, a very wide range of applications can be covered.

T2 mode

In T2 mode both signal inputs of the PicoHarp 300 are functionally identical. There is no dedication of one channel to a sync signal. Usually both inputs are used to connect photon detectors. The events from both channels are recorded independently and treated equally. In each case an event record is generated that contains information about the channel it came from and the arrival time of the event with respect to the overall measurement start. If the time tag overflows, a special overflow marker record is inserted in the data stream, so that upon processing of the data stream a theoretically infinite time span can be recovered at full resolution. Dead times exist only within each channel (90 ns typ.) but not across the channels. Therefore, cross correlations can be calculated down to zero lag time. This allows powerful new applications such as FCS with lag times from picoseconds to hours to be implemented with one instrument. Autocorrelations can also be calculated at the full resolution but of course only starting from lag times larger than the deadtime.

Scheme of the T2 mode of the PicoHarp 300

T3 mode

The T3 mode is specifically designed to use periodic sync signals from mode locked lasers with high repetition rate up to 84 MHz. In this mode one channel is dedicated to the sync signal. As far as the experimental setup is concerned, this is similar to classic TCSPC in histogramming mode. In addition to the picosecond start-stop timing, the events are time tagged with respect to the beginning of the experiment. The time tag is obtained by simply counting sync pulses. From the T3 mode event records it is therefore possible to precisely determine which sync period a photon event belongs to. Since the sync period is also known precisely, this furthermore allows to reconstruct the arrival time of the photon with respect to the overall experiment time. T3 mode measurements always implicitly provide routing information if a router such as the PHR 800 is used. If the counter overflows, a special overflow marker record is inserted in the data stream, so that upon processing of the data stream a theoretically infinite time span can be recovered. Since there is only one photon channel, only autocorrelations can be calculated (unless a router is used).

Scheme of the T3 mode of the PicoHarp 300

External event markers

Both TTTR modes support capturing external marker events that can be fed to the instrument as TTL signals, e.g., via the front panel of the PHR 800. These events are recorded as part of the TTTR data stream. This allows to precisely synchronize the TTTR measurement with almost any experiment. The most important applications of this feature are FLIM and FRET imaging. This concept is used in the cutting-edge time-resolved mircroscope MicroTime 200.

Software support

The acquisition software provided with the instrument comes with a rich set of demo programs that enable users to write their own analysis and display programs for TTTR data. Users who prefer to use standard data analysis algorithms out of the box may want to consider the powerful SymPhoTime 64 software suite. It implements a wide range of state-of-the-art analysis algorithms for FLIM, FCS and FRET to name only a few. Analysis of photon correlations for e.g. coincidence correlation or coincidence counting is best performed with the QuCoa software package.


Latest 10 publications referencing PicoHarp 300

The following list is an extract of 10 recent publications from our bibliography that either bear reference or are releated to this product in some way. Do you miss your publication? If yes, we will be happy to include it in our bibliography. Please send an e-mail to containing the appropriate citation. Thank you very much in advance for your kind co-operation.

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