THORLABS PM100USB User manual

Optical Power Meter
PM100USB
Operation Manual
2017

Version:
Date:
1.3
10-Oct-2017
Copyright © 2017 Thorlabs

Foreword
Contents
2
1General Information 3
31.1 Safety
41.2 Ordering Codes and Accessories
2Parts List 5
3Operating Instruction 6
63.1 Operating Elements
73.2 Connecting a Power Sensor
4Measurement Considerations 8
84.1 Choosing the right sensor
84.2 Reducing Noise for high Accuracy Measurements
94.3 Power Measurement of Pulsed Signals
94.4 Line Width of Light Sources
104.5 Temperature Effects on Thermal Sensors
104.6 Ambient and Stray Light
104.7 Back Reflection
104.8 Beam Diameter vs. Active Sensor Area
114.9 Fiber Based Measurements
114.10Energy Measurement using Pyroelectric Sensors
5 Appendix 13
135.1 Technical Data
165.2 Pin Assignment of the Sensor Connector
175.3 Tutorial
175.3.1 Definitions and explanations
17
5.3.1.1 Console Specifications
18
5.3.1.2 Sensor Specifications
215.3.2 Calculations
245.4 Certifications and Compliances
255.5 Warranty
265.6 Copyright and Exclusion of Reliability
275.7 Thorlabs 'End of Life' Policy (WEEE)
285.8 Thorlabs Worldwide Contacts

© 2017 Thorlabs
We aim to develop and produce the best solution for your application
in the field of optical measurement technique. To help us to live up to
your expectations and improve our products permanently we need
your ideas and suggestions. Therefore, please let us know about
possible criticism or ideas. We and our international partners are
looking forward to hearing from you.
Thorlabs GmbH
Warning
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully, before performing the indicated procedure.
Please read these advices carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
Attention
Paragraphs preceeded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
Note
2

© 2017 Thorlabs
1 General Information
3
1 General Information
The PM100USB Hand-held Optical Power and Energy Meter is designed to
measure the optical power of laser light or other monochromatic or near mono-
chromatic light sources.
The space-saving, battery powered design and compatibility to all Thorlabs “C
Series” Photodiode and Thermal sensors, and custom Photodiode and Thermal
detectors, featured with a fast USB device interface open a wide range of applica-
tions in Manufacturing, Quality Control, Quality Assurance, and R&D for station-
ary and field use.
The provided software, including drivers and applications for LabVIEW and C
makes it easy to integrate the instrument in test and measurement systems.
The unit can be recharged with the supplied AC adapter or via USB connection to
a PC or laptop.
1.1 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 in-
struction manual will only apply when the unit is operated correctly as it
was designed for.
The PM100USB must not be operated in explosion endangered environ-
ments!
Do not obstruct the air ventilation slots in the housing!
Do not remove covers!
Do not open the cabinet. There are no parts serviceable by the operator in-
side!
This precision device is only serviceable if properly packed into the com-
plete original packaging including the plastic foam sleeves. If necessary,
ask for replacement packaging.
Refer servicing to qualified personnel!
Only with written consent from Thorlabs may changes to single compon-
ents be made or components not supplied by Thorlabs be used.
All modules including control inputs / outputs and the sensor must be con-
nected with duly shielded connection cables.
Attention
The following statement applies to the products covered in this manual, un-
less otherwise specified herein. The statement for other products will ap-
pear in the accompanying documentation.

© 2017 Thorlabs4
PM100USB
Note
This equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to part 15 of the FCC Rules. These limits
are designed to provide reasonable protection against harmful interference
when the equipment is operated in a commercial environment. This equip-
ment generates, uses, and can radiate radio frequency energy and, if not in-
stalled and used in accordance with the instruction manual, may cause
harmful interference to radio communications. Operation of this equipment
in a residential area is likely to cause harmful interference in which case the
user will be required to correct the interference at his own expense.
Thorlabs GmbH is not responsible for any radio television interference
caused by modifications of this equipment or the substitution or attach-
ment of connecting cables and equipment other than those specified by
Thorlabs GmbH. The correction of interference caused by such unauthor-
ized 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 viol-
ate FCC and ICES rules.
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.
This product has been tested and found to comply with the limits according
to IEC61326-1 for using connection cables shorter than 3 meters (9.8 feet).
1.2 Ordering Codes and Accessories
PM100USB

© 2017 Thorlabs
2 Parts List
5
2 Parts List
Inspect the shipping container for damage.
If the shipping container seems to be damaged, keep it until you have inspected
the contents and you have inspected the PM100USB mechanically and electric-
ally.
Verify that you have received the following items within the package:
1. PM100USB power/energy meter console
2. USB cable, type ‘A’ to ‘mini-B’
3. Quick-start guide
4. USB memory stick with instrument drivers, user application and operation
manual
5. Certificate of Calibration

© 2017 Thorlabs6
PM100USB
3 Operating Instruction
· Install software from the supplied data carrier (see section Software Installa-
tion).
· Connect a suitable sensor.
· Connect the PM100USB to the PC using the supplied USB cable.
· For detailed instructions, please see section Graphic User Interface.
3.1 Operating Elements
1 Connector for power / energy sensor
2USB connector to PC
3LED: Sensor detected and ready for operation
4LED: USB device ready for operation

© 2017 Thorlabs
3 Operating Instruction
7
3.2 Connecting a Power Sensor
The PM100USB supports all Thorlabs ‘C-Series photodiode, energy and thermal
sensors, that can be easily identified by their red connector housing, compared to
older versions of Thorlabs power sensors. The console will not recognize sensors
from the ‘A’ and ‘B’ series. Please contact Thorlabs for the upgrade of old
sensors with ‘C-Series’ connectors.
To plug or remove a sensor slightly press on the two bolts in the connector hous-
ing, that fix it by resilience.
Sensors can be ‘hot-swapped’ to the console, after recognizing a new valid
sensor the type and calibration data will be downloaded to the console in approx-
imately 2 seconds, and the unit is ready to operate with the new sensor.
The PM100USB also supports custom detectors, please refer to System Settings
for the console measurement settings; the pin-out of the DB9 sensor connector
can be found in Appendix.

© 2017 Thorlabs8
PM100USB
4 Measurement Considerations
4.1 Choosing the right sensor
The question of the right sensor depends on many factors starting with the light
source to measure and the application. No sensor can cover all applications; the
following table shows the main pros and cons of the different power sensor types.
Of course this can only be a rough guide because within each sensor group
there are special models best suitable for specific applications.
Power Sensors:
Light Source
Photo Diode Sensor
Thermal Sensors
Si
Ge
InGaAs
BB
HPB
Volume
Diode Lasers UV - NIR
+++
+
-
++
-
-
Diode Lasers NIR
-
+
+++
++
-
-
High Power Fiber Lasers
-
-
++
++
++
-
ASE Sources
-
-
++
++
-
-
Femtosecond Lasers
-
+
++
++
+
-
Gas Lasers
++
-
-
++
+
-
Excimer Lasers
-
-
-
-
+++
+
YAG Lasers
-
-
-
-
+
+++
LEDs
+
-
-
+++
+
-
4.2 Reducing Noise for high Accuracy Measurements
Noise from grounding, the cable capacitance, temperature effects, stray and am-
bient light and detector noise are interfering the measurement. This impact is the
higher, the lower to measured optical power. Below are given some hints and re-
commendations how to reduce interferences to a minimum:
· The housing of power sensors is connected to the digital ground of the
meter and should be linked to earth ground (e.g. via post mounting).
· Energy sensors should be mounted isolated, because the housing is con-
nected to the meter analog ground.
· The sensor cable conducts very small current or voltage signals. The cable
capacitance induces disturbances when the cable is moved. If very small
power or energy levels are measured, the cable should be fixed in position.
· With photodiode sensors the bandwidth should be set to “Low” setting; with
thermal sensors the acceleration circuit should be shut off.
· The detector noise is lowest with Si or InGaAs sensors.

© 2017 Thorlabs
4 Measurement Considerations
9
· For long term measurements in free space applications it is necessary to
provide constant ambient light conditions, or shielding the light path from
external light sources.
· The temperature should be stable over the time of the measurement.
4.3 Power Measurement of Pulsed Signals
The PM100USB will read the average value of a pulsed signal if the following
conditions apply:
Thermal Sensor
For a thermal sensor, pulse length, repetition rate and peak power are uncritical
as long as the peak power is lower than the damage threshold of the sensor. A
thermal sensor reacts very slow and will integrate the power incident on the active
area of the sensor.
Photodiode Sensor
A photodiode sensor can follow short pulses in the ns range. Therefore, it is im-
portant that the pulse peak power is within the maximum power range of the
sensor. It is also important that the power range is set in such a way, that the
peak power won't exceed this range, otherwise the reading will clip at the end of
the range, which leads to a wrong average value. Furthermore, it is important to
use a power range that can measure the peak value. To find the appropriate
power range, the Min-Max display function is very helpful. Depending on pulse
length and repetition rate, the bandwidth setting will influence the power reading.
It is recommended to use the ‘LOW’ bandwidth setting for a stable display. If the
pulse should be monitored via the analog output, the bandwidth should be set to
‘HIGH’.
4.4 Line Width of Light Sources
The line width of light sources can be neglected only when using a broadband
thermal or pyro-electric sensor.
Photodiode sensors show a strong dependency on the operating wavelength so if
the line width of the light source is greater than 10nm (e.g. LED) there may be an
influence on the displayed power. To achieve the best result for broadband light
sources with a photodiode sensor it is necessary that the response curve is
nearly linear over the line width. When entering the center wavelength of the light
source as operation wavelength, the PM100USB will nearly show the right optical
power for a symmetrical spectral response shape.

© 2017 Thorlabs10
PM100USB
4.5 Temperature Effects on Thermal Sensors
Thermal sensors respond to any temperature differences that occur between
thermal disc and heat sink. The measurement result can be interfered by airflow
disturbances or by heating up the heat sink, e.g., during long-term exposure of
the thermal disc to the laser beam.
To avoid disturbances it is recommended to shield the sensor as good as pos-
sible from airflow and to zero it properly in the operating condition. That means for
short term measurements zero the cold sensor, for long term measurements zero
the sensor when it is in a state of thermal stability (e.g. after 10 minutes light ex-
posure).
4.6 Ambient and Stray Light
Ambient or stray light can strongly affect the measurement accuracy in free-space
applications. A permanent background light level can be subtracted by conducting
a zero adjustment. In case of varying ambient light like daylight or turning on/off
room light, the only solution is a proper shielding of the sensor from ambient and
stray light.
4.7 Back Reflection
The surfaces of photodiodes, ND filters and even the black coatings of thermal
sensors show a certain kind of back reflection of the incoming light. If this back re-
flection hits for example a laser diode or a HeNe laser, this may have an impact
on the power stability of the laser, therefore it is recommended to slightly tilt the
power meter sensor with respect to the laser beam. This way, the back reflection
won't enter the laser.
If back reflections must be completely avoided it is advised to use a S14xC series
integrating sphere sensor where the incoming light gets nearly completely ab-
sorbed in the sensor.
4.8 Beam Diameter vs. Active Sensor Area
Most sensors are not completely uniform in their response over the active area;
except integrating sphere sensors. To overcome uniformity issues the incident
beam should have a diameter larger than 10% of the active sensor area.
Another important point is the maximum allowed power and energy density of the
sensor. The maximum ratings are given in the sensor specifications. The
PM100USB can display the actual power or energy density for a known beam dia-
meter. For high power or high energy beams a good efficiency can be reached by
selecting a sensor with a detector size about 20% - 30% larger than the beam
diameter.
It is also important not to overfill the sensor. That means, that the beam size in
the plane of sensor's active area must not exceed the size of the active area.

© 2017 Thorlabs
4 Measurement Considerations
11
4.9 Fiber Based Measurements
Laser light is emitted from an optical fiber tip in a conical shape, with an angle
twice the acceptance angle of the fiber. The acceptance angle is calculated by:
Θ = n* arcsin (NA)
where NA - numerical aperture of the fiber
n - refraction index; in air n = 1
Fore typical single mode fibers the total angle 2*Q of the emitted light is between
15° and 25°, for an angled connector (APC) the cone is tilted by approximately 4°
from the fiber axis.
This expansion of the beam has to be considered to avoid overfilling the detector
and getting wrong results. On the other hand for measurements with high power
fiber lasers a certain gap between fiber tip and detector surface has to be kept to
decrease the power density.
Thorlabs offers fiber adapters with the most common connectors that are verified
with the S12xC series optical sensors and with most thermal sensors.
For large divergence angles or fiber measurements that are critical to back-reflec-
tions it is recommended to use an integrating sphere sensor of the S14xC series.
Another good choice for fiber based measurements are the fiber heads of the
S15xC series. They plug directly to the meter and have no cable between sensor
and console. This minimizes measurement interferences.
4.10 Energy Measurement using Pyroelectric Sensors
The selection of the best suitable pyroelectric energy sensor must be made with
respect to the following parameters:
Energy to Measure
The maximum allowed energy is limited by the absorption layer (too high energy
causes mechanical damages on the layer) and by the sensor material, that must
not exceed a certain temperature level. It is also important to pay attention to the
maximum energy density, to the average power and to the maximum power dens-
ity during a pulse.
To the lower end, the detection is limited by the resolution and the minimum set-
table trigger level of the display unit, as well as by the noise level. To minimize the
noise level and to avoid ground loops it is recommended to mount the detectors
using the supplied isolation adapters.
Beam Diameter
The active area of the detector should be selected in such way, that it has a
slightly larger diameter than the incident beam. Not necessarily the beam should
cover most of the sensor area, but the maximum allowed energy density must not
be exceeded.
Repetition Rate

© 2017 Thorlabs12
PM100USB
The maximum pulse repetition rate depends on the combination of the internal
capacitance of the detector and the load resistor. The display unit has an input
resistor of 1MΩ (like the typical input resistor of an oscilloscope).
Pulse Length
Energy sensors can detect and measure pulses with a duration from sub-nano-
second range to approximately 2 ms. The max. pulse duration depends on
· the electrical time constant of the sensor, given by detector capacity and load
resistance
· the thermal time constant of the sensor.
Usually the latter is the more significant.
Wavelength
The sensors are typically calibrated at one wavelength, for other wavelengths a
sensor specific correction curve is stored in the memory in the sensor connector.
The black coating is nearly linear flat over a wavelength range from 185nm to >
25µm; the ceramic coating is also suitable for this wavelength range, but is not
linear over the entire wavelength range.

© 2017 Thorlabs
5 Appendix
13
5 Appendix
5.1 Technical Data
General Data
Detector Compatibility
Photodiode Sensors S100C Series
Thermal Sensors S3xxC / S4xxC Series
Pyroelectric Sensors EC100C/ES200C Series
Photodiodes (max. 5 mA)
Thermopiles (max. 1 V)
Pyros (max. 100 V)
Display Type
External PC - Windows Application
Display Update Rate (max)
Up to 300 Hz, depending on PC and settings
Display Format
Numerical, Bar Graph, Trend Graph, Statistics, Histogramm
(Utility Software)
Current Input (Photodiode Sensors)
Connector
DB9F, left side
Units
W, dBm, W/cm², A
Measurement Ranges
6 decades; 50 nA - 5 mA
Ranges selectable in W or A, sensor depending
Display Resolution
1 pA / responsivity value (A/W)
AD Converter
16 bit
Accuracy
± 0.2 % f.s. (5µA - 5mA)
± 0.5 % f.s. (50nA)
Input Bandwidth (Analog)
DC - 100kHz, depending on sensor and settings
Wavelength Correction
nm (A/W)
Beam Diameter Setting
1/e²
Voltage Input (Thermopile Sensors)
Connector
DB9F, left side
Units
W, dBm, W/cm², V
Measurement Ranges
4 decades; 1 mV - 1V
Ranges selectable in W or V, sensor dependent
Display Resolution
1 µV / responsivity value (V/W)
AD Converter
16 bit
Accuracy
± 0.5 % f.s. (10 mV - 1 V range)
± 1.0 % f.s. (1 mV range)
Input Bandwidth (Analog)
DC - 10Hz, depending on sensor and settings
Wavelength Correction
Sensor depending; nm, (V/W)
Beam Diameter Setting
1/e²

© 2017 Thorlabs14
PM100USB
Voltage Input (Pyroelectric Sensors)
Connector
DB9F, left side
Units
J, J/cm², W, W/cm², V
Measurement Ranges
4 decades; 100 mV - 100V
Ranges selectable in J or V, sensor dependent
Display Resolution
100 µV / responsivity value (V/J)
AD Converter
16 bit
Accuracy
± 0.5 % f.s.
Trigger Threshold
0.1 % to 99.9 % f.s.
Input Bandwidth (Analog)
3 kHz
Input Impedance
1 M W
Wavelength Correction
Sensor depending; nm, (V/J)
Beam Diameter Setting
1/e²
Sensor Temperature Control
Supported temperature sensor
Thermistor
Temperature measurement range
-10°C ... +80°C
Interface
Type
USB2.0
Connector
Mini USB, left side
Power Supply
External power supply
5V DC via USB
Accessories
USB cable A to Mini-B, 2 m
USB Stick with
- Application Software
- Instrument Drivers
- Thorlabs Instrument Communicator
- Thorlabs DFU (Device Firmware Upgrade) Wizard
General
Operating Temperature Range 1)
0 to + 40 °C
Storage Temperature Range
-40 to +70 °C
Dimensions (W x H x D)
93.1 mm x 60.4 mm x 28.7 mm
(3.67" x 2.38" x 1.13")
Weight
approx. 0.15 kg
Relative Humidity
max. 80 % up to 31° C, decreasing to 50 % at 40° C
Operation Altitude
< 3000 m
1) non-condensing
All technical data are valid at 23 ± 5°C and 45 ± 15% rel. humidity (non condensing)

© 2017 Thorlabs
5 Appendix
15
Current Input Photo Diode Sensors
Current Range
Display Resolution
Measurement Accuracy
5 mA
1µA
± 0.2 % f.s.
500 µA
100 nA
50 µA
10 nA
5 µA
1 nA
500 nA
100 pA
50 nA
10 pA
± 0.5 % f.s.
Voltage Input Thermal Sensors
Voltage Range
Display Resolution
Measurement Accuracy
1 V
100 µV
± 0.5 % f.s.
100 mV
10 µV
10 mV
1 µV
1 mV
0.1 µV
± 1.0 % f.s.
Voltage Input Pyroelectrical Sensors
Voltage Range
Display Resolution
Measurement Accuracy
100 V
100 mV
± 0.5 % f.s.
.
10 V
10 mV
1 V
1 mV
0.1V
100 µV

© 2017 Thorlabs16
PM100USB
5.2 Pin Assignment of the Sensor Connector
The PM100USB is capable to support custom made detectors. Please read care-
fully the following instruction prior to connecting a self made sensor.
Pin-out of the 9pin DSUB
sensor connector (female)
pin connection
3AGND (analog ground): photodiode ground (anode), thermal and pyro
sensor ground
4photodiode cathode
5pyroelectric sensor +
8thermal sensor +
7PRESENT: Connect this pin via a 1kΩ – 10kΩ resistor to pin 3
(AGND) to enable a custom sensor
1+5V (max. current 50mA from this pin)
6DGND (digital ground)
9 n.c.
Warning
Pin 2 is uniquely used for the EEPROM Digital I/O (memory in Thorlabs sensor
heads) and MUST NOT be used. Connecting this pin may cause malfunction of
the PM100USB.

© 2017 Thorlabs
5 Appendix
17
5.3 Tutorial
Content
Definitions and explanations: This section gives an overview on specifications,
their definitions and application to sensor families.
Calculations: Here common formulas are given - power, energy and densities can
be calculated based on different given parameters.
5.3.1 Definitions and explanations
In this section the key parameters of Thorlabs Power Meters and Sensors are
commented.
5.3.1.1 Console Specifications
· Measurement Ranges
It is important to keep in mind, that the optical power (energy) measurement is
based on a current measurement (photodiode sensors) or on a voltage meas-
urement (thermal and pyroelectric sensors). That's why the measurement
ranges are stated sensor dependent - for photodiode sensors are stated the
current ranges, for thermal and energy sensors - voltage ranges.
· Display Resolution
Note:
The resolution is the minimum detectable change of power (energy), it is not
the minimum measurable power (energy)!
As the console measures a current or a voltage, the display resolution can be
stated only in A or V. In the specifications the resolution is stated for the most
sensitive measurement range. The optical power resolution depends on the ac-
tual sensor's responsivity.
Current input (photodiode sensors): The resolution is specified to "1 pA / re-
sponsivity value (A/W)". This means, that the PM100USB has in the lowest
measurement range (50 nA) a resolution of 1 pA. The responsivity of a photo
diode sensor is wavelength dependent, thus the power resolution is wavelength
dependent as well.
Example: A S120C sensor has a responsivity of 7.35 × 10-2 A/W at 930 nm,
and 5.05 × 10-3 A/W at 455 nm. In the lowest measurement range the displayed
power resolution is at 930 nm
and at 455 nm

© 2017 Thorlabs18
PM100USB
In contrast to above resolution values, the minimum measurable optical power
for S120C is 50 nW. This should make clear the difference between resolution
and minimum power.
Voltage input (thermopile sensors): The resolution is specified to "1 µV / re-
sponsivity value (V/W)". This means, that the PM100USB has in the lowest
measurement range (1 mV) a resolution of 1 µV. The power resolution depends
on the used sensor.
Voltage input (pyroelectric sensors): The resolution is specified to "100 µV /
responsivity value (V/J)". This means, that the PM100USB has in the lowest
measurement range (200 mV) a resolution of 100 µV. The energy resolution
depends on the used sensor.
· Accuracy of the PM100USB is the current (voltage) measurement accuracy. It
is given in % f.s. (% of the full scale value). Please note that the console's ac-
curacy is different from the sensor's measurement uncertainty.
· Wavelength Correction is value that can be entered to the console in order to
apply the correct responsivity and to get this way a correct measurement res-
ult.
In case of a calibrated Thorlabs sensor, the actual wavelength is entered dir-
ectly. The console retrieves the according responsivity from the calibration
table, which is saved to the sensor's memory, and uses this value for power
(energy) calculation.
In case of a custom sensor, the console needs to be set to the correct sensor
type (photodiode, thermal or pyroelectric sensor) and the responsivity needs to
be entered as numerical value.
5.3.1.2 Sensor Specifications
1. Common parameters
· Wavelength Range: Within this range the sensor is calibrated and thus able
to measure with the specified measurement uncertainty.
· Resolution is the minimum detectable change of the measured parameter.
The resolution is always specified for a certain console type and bandwidth
setting.
· Measurement uncertainty states the measurement accuracy and is specified
for the entire wavelength range of the sensor. For some sensor types, an al-
ternative value might be specified for a partial wavelength range.
2. Photo Diode Sensors (S12xC, S13xC and S15xC Series)
· Optical Power Range specifies the minimum and maximum measurable
power. Exceeding the upper limit leads to sensor saturation and wrong meas-
urement results. If pulsed signals are measured, the pulse peak power must