THORLABS SPCNT User manual

SPCNT
Single Photon Counting Device
2023
User Guide

Version:
Date: 1.0 30-May-2023
Copyright © 2023Thorlabs

SPCNT Single Photon Counting DeviceTable of Contents
Chapter 1 Safety 1
Chapter 2 Intended Use 2
Chapter 3 Introduction 2
3
3.1 Ordering Codes and Accessories 3
3.2 Requirements
Chapter 4 Getting Started 3
3
4.1 Parts List 4
4.2 Operating Elements 4
4.3 Setup 5
4.4 Software Installation 5
4.5 Compatible Detectors
Chapter 5 Operation 6
6
5.1 SMA Connectors 7
5.2 Operation without a Connected PC 7
5.3 Optical Power Monitor 8
5.3.1 Devices 14
5.3.2 Monitoring 16
5.3.2.1 Logging Settings 17
5.3.3 Data Viewer 17
5.3.4 Help 18
5.4 Write Your Own Application
Chapter 6 Operating Principle 20
20
6.1 Measurement Modes
Chapter 7 Specifications 22
23
7.1 Dimensions
Chapter 8 Maintenance and Service 23
Chapter 9 Certifications and Compliances 24
Chapter 10 Warranty and RMA Information 25
25
10.1 Return of Devices 25
10.2 WEEE Policy
Chapter 11 Manufacturer Address 25
Chapter 12 Copyright and Exclusion of Liability 26

SPCNT Single Photon Counting Device
Chapter 13 Thorlabs Worldwide Contacts 27

Rev: 1.0, 30-May-2023 © 2023Thorlabs Page 1
SPCNT Single Photon Counting Device Chapter 1 Safety
Chapter 1 Safety
Attention
The safety of any system incorporating the equipment is the responsibility of the assembler of the
system.
All statements regarding safety of operation and technical data in this instruction manual will only
apply when the unit is operated correctly as it was designed for.
The SPCNTmust not be operated in explosion endangered environments!
Do not obstruct the air ventilation slots in the housing!
Do not remove covers!
Do not open the cabinet. There are no user-serviceable parts inside!
This precision device is only serviceable if returned and properly packed into the complete original
packaging including the cardboard inserts. If necessary, ask for replacement packaging.
Refer servicing to qualified personnel!
Changes to this device cannot be made nor may components not supplied by Thorlabs be used without
written consent from Thorlabs.
Attention
The following statement applies to the products covered in this manual, unless otherwise specified
herein. The statement for other products will appear in the respective accompanying documentation.
Note This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15of the FCC Rules and meets all requirements of the Canadian Interference-Causing
Equipment Standard ICES-003 for digital apparatus. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However, there is no guarantee
that interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment off
and on, the user is encouraged to try to correct the interference by one or more of the following
measures:
·Reorient or relocate the receiving antenna.
·Increase the separation between the equipment and receiver.
·Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
·Consult the dealer or an experienced radio/T.V. technician for help.
Users that change or modify the product described in this manual in a way not expressly approved by
Thorlabs (party responsible for compliance) could void the user’s authority to operate the equipment.
Thorlabs is not responsible for any radio television interference caused by modifications of this
equipment or the substitution or attachment of connecting cables and equipment other than those
specified by Thorlabs. The correction of interference caused by such unauthorized modification,
substitution or attachment will be the responsibility of the user.
The use of shielded I/O cables is required when connecting this equipment to any and all optional
peripheral or host devices. Failure to do so may violate FCC and ICES rules.

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SPCNT Single Photon Counting Device Chapter 1 Safety
Attention
Mobile telephones, cellular phones or other radio transmitters are not to be used within the range of
three meters of this unit since the electromagnetic field intensity may then exceed the maximum
allowed disturbance values according to IEC 61326-1.
Chapter 2 Intended Use
The SPCNT Single Photon Counting Device counts pulse events such as those generated with single
photon detectors. It is used in photonics research and development applications.
The SPCNT single photon counting device is designed for laboratory use only. This product may not be
used or integrated into equipment that is applied in pharmaceutical, medical or military applications.
Thorlabs, Inc. Life Support and Military Use Application Policy is stated below:
THORLABS’ PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS OR IN ANY MILITARY APPLICATION WITHOUT THE EXPRESS WRITTEN APPROVAL OF
THE PRESIDENT OF THORLABS, INC. As used herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and whose failure to perform, when properly used in
accordance with instructions for use provided in the labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component in a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system or to affect its
safety or effectiveness.
3. The Thorlabs products described in this document are not intended nor warranted for usage in
Military Applications.
Chapter 3 Introduction
The Thorlabs SPCNT Single Photon Counting Device recognizes pulses originating from a connected
single photon detector and shows the results numerically as counts or frequency either on the built-in
display or a connected PC for further analysis. The SPCNT is connected to the PC via the USB port, and
can be controlled by Thorlabs' Optical Power Monitor (OPM) software, which can also monitor and save
the counting results.
The SPCNT single photon counter excels in combination with the Thorlabs single photon detectors
SPDMA and the SPDMHx Series. The signal monitor output (MONITOR TTL port, SMA connector) allows
the counts or frequency of signal pulses to be observed by a separate counter or an oscilloscope. Signal
counting can be activated or stopped by an external signal generator.
Additionally, Thorlabs provides the Standard Commands for Programmable Instruments (SCPI) to
generate custom made software for the remote control of the SPCNTcounting device.
Attention
Please find all safety information and warnings concerning this product in the chapter Safety.

Rev: 1.0, 30-May-2023 © 2023 Thorlabs Page 3
SPCNT Single Photon Counting Device Chapter 3 Introduction
3.1 Ordering Codes and Accessories
SPCNT
Single Photon Counting Device
Required Accessories:
For direct operation without connection to a PC via USB 2.0, please use an external power supply with
the specifications stated in the chapter Specifications. The Thorlabs DS5 power supply is
recommended.
Single Photon Detector
1. SPDMA Single Photon Detection Module with Adjustable Gain
or
2. SPDMHx Single Photon Detection Modules with Fixed Gain
3.2 Requirements
These are the requirements for the PC intended to be used for remote operation of the SPCNT.
Software Requirements
The SPCNT can be run with the Thorlabs Optical Power Monitor software (OPM). Please see the
requirements for the OPMon the OPMwebsite.
Chapter 4 Getting Started
4.1 Parts List
Please inspect the shipping container for damage. Please do not cut through the cardboard, as the box
might be needed for storage or returns.
If the shipping container appears to be damaged, keep it until you have inspected the contents for
completeness and tested the SPCNT mechanically and electrically.
Verify that you have received the following items within the package:
1. SPCNT Single Photon Counting Device
2. USB 2.0Cable: Cable Length 1.5 m
3. Quick Reference

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SPCNT Single Photon Counting Device Chapter 4 Getting Started
4.2 Operating Elements
SPCNT Left Side Panel
SPCNT Right Side Panel
4.3 Setup
1. Download and install the Optical Power Monitor software (OPM) to the computer (PC/laptop)
that will be used to control the counting device.
Note Install the software prior to connecting the counting device to the PC.
2. Connect the SPCNTcounting device to the PC/laptop using the supplied USB 2.0cable (1.5m
length). For direct operation without a PC, connect the SPCNT via the USB connector to a suitable
power supply. The Thorlabs DS5power supply is recommended.
3. Connect a compatible detector on the INPUT connector (SMA). The sensor may also be connected
or exchanged at a later point.
4. The SPCNTcounting device is now ready for operation and is recognized by the OPMsoftware. In
case the SPCNT is not automatically recognized, please see the section troubleshooting.

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SPCNT Single Photon Counting Device Chapter 4 Getting Started
5. If not already done in (3), connect a compatible detector to the SPCNT counting device or
exchange the sensor connected previously.
6. Configure the SPCNT counting device in the Thorlabs OPMsoftware as described in the section
Optical Power Monitor.
7. The counts can now be monitored either via the OPMsoftware or on the SPCNT display directly.
Note In addition to using the Thorlabs software Optical Power Monitor, the user can build custom
made software with the help of the SCPI commands saved within the OPM software. Please see the
chapter Write-Your-Own-Application for further instructions.
4.4 Software Installation
Attention
Exit all running applications on your PC as the installer may require a reboot of your PC during
installation!
The Optical Power Meter (OPM) Software can be downloaded from the Thorlabs website:
https://www.thorlabs.com/software_pages/ViewSoftwarePage.cfm?Code=OPM
Note Do not connect a Thorlabs device to the PC during software installation! Please make sure that
the installation is carried out completely, including the reboot requests.
·Save the ZIP file to your computer and unpack the archive.
·Double click the setup.exe to start the Install Shield Wizard.
·Read and accept the End-User License Agreement and the GNULesser General Public License.
·After installing the OPM, connect the counting device to the PC.
Start Application
Start the Optical Power Meter Software from the desktop icon:
or access the OPMfrom the START button:
4.5 Compatible Detectors
The SPCNT counting device is compatible with all Thorlabs single photon detectors.
1. SPDMA Single Photon Detection Module with Adjustable Gain
or
2. SPDMHx Single Photon Detection Modules with Fixed Gain

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SPCNT Single Photon Counting Device Chapter 5 Operation
Chapter 5 Operation
The SPCNT single photon counting device receives an input signal from a single photon detector,
arriving at the INPUT connector (SMA). The device then counts and analyzes the signal with the default
settings for bin width, dead time, and threshold. The results are shown on the device display. Please
see the chapter Specifications on technical information concerning the compatible input signal. The
buttons DIM and VIEW next to the display allow the user to dim the display, switch between the display
or counts or frequency, and to ZERO the signal in order to eliminate background. Please find more
information on operation directly on the SPCNT in the chapter Operation without a Connected PC.
When connected to a PC, incoming signal is analyzed according to settings in the remote software
Optical Power Monitor (OPM): bin width, dead time, zero level, and threshold. As an alternative to the
internal binning, set within the software, the signal can be gated with an external signal generator via
the TRIG IN connector.
Please find information on how to download the OPM software in the chapter Software Installation.
The operation of the SPCNT, using the OPM software, is described in the chapter Optical Power
Monitor.
Alternatively, custom made software can be generated with the help of the provided SCPI commands.
For more information, please see the chapter Write-Your-Own-Application (WYOA).
5.1 SMA Connectors
The SPCNT counting device has three SMA connector for signal input, montior output, and for input of
an external signal measurement gating.
Signal Input
The SMA connector INPUT receives the pulse signal from a connected single photon detector.
Please find the technical data for the INPUTport in the Specifications.
Monitor Output
The monitor output SMA connector provides to access the pulses of the input signal with another
external counter or oscilloscope. The monitor output signal is not identical to the input signal, as the
Schmitt Trigger (see chapter Operating Principle) between Input and Monitor Output applies the
threshold.
Please find the technical data for the monitor output port in the Specifications.
External TRIG IN Signal
An external active high TTL signal can be applied to define the bin width or dead time via external
hardware. Use the measurement mode "Gated" in the interface Devices in the OPMsoftware.
The technical data for the external TRIG IN signal is provided in the chapter Specifications.

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SPCNT Single Photon Counting Device Chapter 5 Operation
5.2 Operation without a Connected PC
The SPCNT can be used to monitor counts or their frequency directly on the device display. In this case
the default settings, which are listed below, are applied to the SPCNT.
For applications without a connected PC, a power supply is required. Please see the chapter
Specifications for the power supply requirements. The Thorlabs DS5power supply is recommended.
Switch between display of counts or frequency by pressing the button VIEWon the device front panel.
Dim the display for sensitive applications by pressing the button DIM on the device front panel.
Pressing the DIM button multiple times lowers the light level until the display is dark. Pressing again
return the display to full brightness.
To ZERO the signal in order to eliminate background, simultaneously apply a short press to the buttons
DIMand VIEW .
Default Settings:
·Bin Width: 500ms
·Dead Time: 0ms
·Threshold: 40%
Please refer to the chapter Optical Power Monitor for explanations on the settings.
5.3 Optical Power Monitor
After connecting of the SPCNT counting device to the PC running the installed OPM software, open the
software and select the SPCNT as the active device in the left panel.
The OPM software will then show the following interface. The following chapters describe the
functions for the SPCNT in the OPMsoftware.

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SPCNT Single Photon Counting Device Chapter 5 Operation
5.3.1 Devices
The Devices menu administers the currently connected devices, short-term measurements and the
respective settings.
To start a measurement, follow the sequence suggested by the menu bar from left to right:
·Activate Devices
·Adjust Settings
·Observe the Measurement
In the following interface, adjust the settings for the SPCNT:
1. Active Devices Panel
This left panel lists the recognized, connected devices.
Additional devices (up to 8SPCNT in parallel) may be added via the icon .
To change the displayed name or assign a color in the OPM for a selected device, click the icon .
Disconnect devices via the link icon .
2. Settings Panel
Use the settings panel to configure the SPCNT counting device.
a. Display - Parameter: Select between display of Frequency or Counts in the main panel
Measurement.
b. Device:
i. Measurement Mode: Choose between Internal Binning to set the binning from within the
OPM software, or Gated to use a TTL start/stop signal from an external device to define the
binning. Please see the chapter Measurement Modes for more information on the modi
Internal Binning and Gated.

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SPCNT Single Photon Counting Device Chapter 5 Operation
Internal Binning
Use internal binning to set binning from within the OPM software. Internal Binning provides
adjustment of the following parameters:
1. Bin Width [ms]
The bin width determines the duration within which pulses are counted.
The displayed frequency is calculated based on the number of pulses during the set bin
width.
Counts
Frequency Bin Width * 1000 =
Please see the chapter Operating Principle for more information.
Internal Binning (Default)
2. Dead Time [ms] introduces a periodic interruption between bins. During the dead time,
pulse counts are discarded. The dead time can be configured between 0 seconds
(disabled) and 6seconds with a microsecond accuracy. An example is shown in the figure
below.
Please see the chapter Operating Principle for more information.
Internal Binning With Dead Time
Gated
In Gated mode, an external device provides an Active High TTL Signal to define the binning.
The OPM software in Gated mode provides adjustment via the following interface with the
parameters described below:

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SPCNT Single Photon Counting Device Chapter 5 Operation
ii. Zero Adjust eliminates background noise originating from the connected Single Photon
Detector or other unwanted background signal. When connected to a PC running the OPM
software, the zero button on SPCNT device is disabled. To set Zero to eliminate background,
set up the detector as used but in the absence of the desired signal. Cover the detector and
click the icon .
iii. Threshold [%] defines the signal level above which signal is counted. This function can be
used to eliminate afterpulsing. The default settings for the threshold are optimal for the
Thorlabs SPDMA and SPDMHx single photon detectors. To compensate for afterpulsing in
other detectors, first determine the afterpulsing characteristics of the connected single
photon detector and then set the threshold level.
iv. Display Brightness adjusts the brightness of the display.
3. Information Panel
The panel Information shows the Name of the device, the serial number as well as the firmware
revision.
4. Measurement Panel
The panel Measurement displays the numeric counts or frequency data as set in the settings panel as
shown above. Click the refresh icon to reset the cumulative value that is displayed.

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SPCNT Single Photon Counting Device Chapter 5 Operation
As in other applications of the Optical Power Monitor software, click the icon +to add display of
more features.
5. Statistics
The Statistics panel shows the measurement statistics in chart and table format. This data can be
recorded via the icon .

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SPCNT Single Photon Counting Device Chapter 5 Operation
to set the duration of the acquired statistics and the recording duration.
to save statistics, which were acquired just before via ,or a recording
to switch to the last or next statistics frame which was recorded via the icon .
to record statistics data within the duration set via the icon . During the recording, the
following interface appears:
These icons start, pause, and stop acquisition and running display of acquired signal,
respectively.
to refresh the statistics during an acquisition period.

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SPCNT Single Photon Counting Device Chapter 5 Operation
6. Graph
The Graph panel shows the signal over time either as frequency or counts, as selected under
Settings-Display - Parameter.
to set the duration of the acquired graph and the recording duration.
to save a graph, which was acquired just before via ,or a recording
to switch to the last or next graph frame which was recorded via the icon .
to record graph within the duration set via the icon . During the recording, the following
interface appears. The Recording can be saved via the icon

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SPCNT Single Photon Counting Device Chapter 5 Operation
These icons start, pause, and stop acquisition and running display of acquired signal,
respectively.
to refresh the graph display during an acquisition period.
5.3.2 Monitoring
Use the Monitoring panel to configure, execute, observe, and save long-term monitoring of up to 8
connected SPCNTs in parallel in Frequency and Counts. Long-term measurements can be recorded with
a minimal interval of 0.1second.
The Monitoring interface has three sections from left to right:
1) Table: The table lists the connected SPCNT devices which are selected for logging in the Monitoring
interface. To select them, click the settings icon .

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SPCNT Single Photon Counting Device Chapter 5 Operation
2) Logging Chart: This panel displays the frequency or counts over time according the settings selected
under the setting icon . The region of interest in the graph, display of the legend and marks of
certain data points can be selected in the panel above the graph. In general, these features are
analogous to the features described in the full OPMmanual.
3) Setting and Information: Use the settings panel to configure and start the long-term data logging. A
description on the settings options is in the next chapter Logging Settings.
The monitoring panel looks as follows during a measurement with the Information panel to the right:

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SPCNT Single Photon Counting Device Chapter 5 Operation
5.3.2.1 Logging Settings
Configure the logging of a measurement and select the output file format, location, and name, and set
the duration and resolution for logging under Settings.
Please read the section File Format in the OPMmanual to learn about the data saved in the log files.
Review the Logging Settings prior to starting the measurement:
Save as: Choose to save data either as single files or
multiple files, depending on the data volume.
oSingle files: The OPM software saves a .csv file for
short measurements with small data volume.
oMultiple files: The OPM software saves multiple .cvs
files for measurements with large data volumes such as
longer measurements or measurements with multiple
SPCNT devices in parallel. When the software saves
multiple files, an associated .tcsv file is saved for
accelerated loading of data into the data viewer. Do not
move or delete any files from the common folder. Please
find more information in the section File Format in the
OPMmanual.
File Path: Select the Output File location.
File Name: Choose the file name.
Delimiter and Decimal separator: Choose the Delimiter
and Decimal separator for easy access and analysis of
your saved data.
Saving Interval: Set the time interval between saved data
points. The minimal interval is 0.1second.
Stop Condition: Select the criteria for terminating the
logging process.
oSize: Measure up to a file size of 99999MB
oDuration: Measure for a certain duration.
oNumber of Samples: Measure a set number of samples.
oManual: Stop logging manually.
Note
Logging can not be started if no parameters were selected in the table section of the monitoring panel.
Attention
Disable hibernation and sleep mode of the PC. Otherwise, the PC looses the connection to the
monitored devices, the measurement stops, and the OPM software may freeze when entering sleep
mode or hibernation.
Start Logging
Click this button to start logging of the measurement. If the file name was already used, a warning
window appears.
The Logging Settings panel will change to the Logging Information panel and show the status of the
measurement.