Compact USB Power Meters

Overview
Specs
Software
Pulse Calculations
Feedback

Compact USB Power Meter with Computer Interface

Click to Enlarge
The PM16-140C Integrating Sphere Power Meter connected to a laptop running the optical power monitor software.

Features

USB 2.0 Power Meter Interface
USB Stick Dimensions: 65 mm x 20 mm x 10 mm (2.60" x 0.80" x 0.40")
Choose from Four Sensor Head Formats
- Standard Photodiodes: 400 to 1800 nm
- Slim Photodiode: 400 to 1100 nm
- Integrating Spheres: 350 to 1700 nm
- Thermal Sensor: 190 nm to 20 µm
Compatible Fiber Connector Adapters Available Below
All Sensor Heads Are Post Mountable
Controlled via the Optical Power Monitor Software Package on Computers Running the Windows^® Operating System (See the Software Tab for Details)

Thorlabs has integrated some of our most popular sensor head formats with a compact USB power meter interface that can be operated using a computer running the optical power monitor software (see the Software tab for download information). Sensor head options include our standard photodiode sensors, a slim-format photodiode sensor, integrating spheres, and a thermal sensor. A 1.5 meter cable* connects the sensor head to the power meter electronics, which are contained in a compact 65 mm x 20 mm x 10 mm (2.60" x 0.80" x 0.40") USB package. The power meter can be controlled by Thorlabs' Optical Power Monitor software installed on a computer running one of the Windows^® 7 (SP1) through Windows 10 operating systems (see the Software tab for download information).

Standard Photodiode Sensors
Three of these power meters use Thorlabs' standard photodiode sensors and are available with either a silicon photodiode for 400 to 1100 nm or a germanium photodiode for 700 to 1800 nm. The PM16-120 and PM16-121 silicon photodiode sensors can detect optical powers between 50 nW to 50 mW and 500 nW to 500 mW, respectively, while the PM16-122 germanium photodiode sensor is designed to measure optical powers between 50 nW and 40 mW. Photodiode sensors are an excellent choice for applications that require a fast response time or high resolution but do not need a sensor with a flat spectral response.

Slim Photodiode Sensor
The PM16-130 power meter uses one of Thorlabs' slim photodiode sensor heads, ideal for applications with limited space and accessibility. The sensor head uses a large-area silicon photodiode sensitive to wavelengths between 400 to 1100 nm in a compact package that is just 5 mm thick on the sensor side. A built-in, slideable neutral density filter allows this power meter to take measurements of optical powers between 500 pW and 5 mW (without filter) or up to 500 mW (with filter).

Integrating Sphere Photodiode Sensors
Integrating sphere sensors can provide entrance-angle-independent power measurements of non-uniform or diverging beam shapes. They are available with either a silicon photodiode sensor for 350 to 1100 nm (Item # PM16-140) or a germanium photodiode sensor for 800 - 1700 nm (Item # PM16-144). Both sensors can detect optical powers between 1 µW and 500 mW.

Thermal Power Sensors
Three of Thorlabs' Thermal Power Sensors are available with the compact USB power meter interface. Thermal sensors are well suited for use in a wide range of applications, particularly those requiring a flat spectral response. They are additionally useful for applications with ultrashort pulses where high peak power would saturate a photodiode sensor. The S401C and S405C sensor heads provide low-power, ≤1 W and ≤5 W, respectively) and high-resolution (1 µW and 5 µW, respectively) measurements, and the S401C additionally uses active background compensation for low-drift measurements. The S425C has a fast response (<0.6 s) and accepts continuous optical inputs up to 10 W.

USB Power Meter Interface
These extremely compact power meters feature similar internal electronics to Thorlabs' PM160 and PM160T Wireless Power Meters and can be controlled via a computer running the optical power monitor software (see the Software tab).

All of the power meters available on this page have externally SM1-threaded input apertures or included adapters, except for the PM16-130 for which the SM1A29 adapter (available below) must be purchased separately. These threads allow the sensor heads to be used with our selection of internally SM1-threaded fiber adapter caps, available below.

Calibration
Each sensor head is individually calibrated and is shipped with a NIST- and PTB-traceable calibration certificate. The calibration and identification data is stored in the power meter's USB stick housing and applied to calculate accurate power measurements. For more information on sensor calibration, please see the Calibration tab on our Power Meter and Sensor Tutorial.

Recalibration Services
Thorlabs offers recalibration services for all of our power meters. To ensure accurate measurements, we recommend recalibrating the sensors annually. To order this service, scroll to the bottom of the page and select the appropriate Item # that corresponds to your power meter.

If you are interested purchasing a Thorlabs sensor head with a compact USB power meter interface that is not offered below, please contact Tech Support for information on custom options.

*If a longer cable length than 1.5 m is required, Thorlabs also offers USB extension cables in a variety of lengths.

USB Power Meters with Standard Photodiode Sensors

Item #	PM16-120	PM16-121	PM16-122
Detector Type	Large Area Silicon Photodiode		Large Area Germanium Photodiode
Wavelength Range	400 - 1100 nm		700 - 1800 nm
Optical Power Measurement Range	50 nW - 50 mW	500 nW - 500 mW	50 nW - 40 mW
Optical Power Resolution	<1 nW	<10 nW	<2 nW
Calibration Uncertainty^a,b	±3% (451 - 1000 nm) ±5% (Over Rest of Range)		±5%
Linearity	±0.5%
Active Area Uniformity^b	±1%
Max Average Power Density	20 W/cm²		10 W/cm²
Optical Filter / Diffuser	Reflective ND (OD1)	Reflective ND (OD2)	Absorptive ND (Schott NG9)
Response Time	<1 µs
Sensor Active Area	9.7 mm x 9.7 mm
Sensor Aperture	Ø9.5 mm
Power Meter Electronics Properties
Analog Measurement Ranges^c	500 nA, 50 µA, 5 mA
Measurement Units	W, dBm, A
AD Converter	24 Bit
Analog Amplifier Bandwidth	10 Hz
Update Rate	10 Hz
Remote Interface	USB 2.0
Power Supply	External: 5 V DC via USB
Dimensions
Sensor Head Dimensions	Ø30.5 mm x 12.7 mm (1.20" x 0.50")
USB Housing Dimensions (Including Plug)	65 mm x 20 mm x 10 mm (2.60" x 0.80" x 0.40")
Cable Length	1.5 m
Weight	0.07 kg
Mounting
Aperture Thread	External SM1 (1.035"-40)
Post Mounting	8-32 and M4 Combined Tap
Compatible Fiber Adapter Item #'s	S120-FC, S120-APC, S120-SMA, S120-ST, S120-SC, S120-LC (Not Included)

This is the maximum error that may appear during calibration taking the tolerances of performance for all equipment into account.
Beam Diameter > 1 mm.
The appropriate range is chosen internally by the power meter to achieve the best accuracy. Automatic ranging can be turned off.

USB Power Meter with Slim Photodiode Sensor

Item #	PM16-130
Detector Type	Large Area Silicon Photodiode
Wavelength Range	400 - 1100 nm
Optical Power Measurement Range	500 pW - 5 mW (Up to 500 mW with Filter)
Optical Power Resolution	<100 pW (10 nW with Filter)
Calibration Uncertainty^a,b	±3% (451 nm - 1000 nm) ±5% (Over Rest of Range)
Linearity	±0.5%
Active Area Uniformity^b	±1%
Max Average Power Density	20 W/cm²
Max Pulse Energy Density	0.2 J/cm² (1 µs Pulse), 2 J/cm² (1 ms Pulse)
Optical Filter / Diffuser	Reflective ND (OD2) with Diffuser
Response Time	<1 µs
Sensor Active Area	9.7 mm x 9.7 mm
Sensor Aperture	Ø9.5 mm
Power Meter Electronics Properties
Analog Measurement Ranges^b	500 nA, 50 µA, 5 mA
Measurement Units	W, dBm, A
AD Converter	24 Bit
Analog Amplifier Bandwidth	10 Hz
Update Rate	10 Hz
Remote Interface	USB 2.0
Power Supply	External: 5 V DC via USB
Dimensions
Sensor Head Dimensions	150.0 mm x 19.0 mm x 10.0 mm (5.91" x 0.75" x 0.39") 5 mm Thickness on Sensor Side
USB Housing Dimensions (Including Plug)	65 mm x 20 mm x 10 mm (2.60" x 0.80" x 0.40")
Cable Length	1.5 m
Weight	0.125 kg
Mounting
Aperture Thread	External SM1 (1.035"-40) Threads with Optional Adapter Item #: SM1A29 (Not Included)
Post Mounting	8-32 and M4 Taps
Compatible Fiber Adapter Item #'s	S120-FC, S120-APC, S120-SMA, S120-ST, S120-SC, S120-LC (Not Included) When Used with Optional SM1A29 Adapter

This is the maximum error that may appear during calibration taking the tolerances of performance for all equipment into account.
Beam Diameter > 1 mm.
The appropriate range is chosen internally by the power meter to achieve the best accuracy. Automatic ranging can be turned off.

USB Power Meters with Integrating Sphere Sensor

Item #	PM16-140	PM16-144
Detector Type	Integrating Sphere (Silicon Photodiode)	Integrating Sphere (InGaAs Photodiode)
Wavelength Range	350 - 1100 nm	800 - 1700 nm
Optical Power Measurement Range	1 µW - 500 mW
Optical Power Resolution	<1 nW
Calibration Uncertainty^a	±3% (451 nm - 1000 nm) ±5% (Over Rest of Range)	±5%
Linearity	±0.5%
Max Average Power Density	1 kW/cm²
Integrating Sphere Material / Diameter	Zenith^® PTFE Integrating Sphere / Ø1"
Response Time	<1 µs
Sensor Active Area	3.6 mm x 3.6 mm	Ø2 mm
Sensor Aperture	Ø5 mm	Ø5 mm
Power Meter Electronics Properties
Analog Measurement Ranges^b	500 nA, 50 µA, 5 mA
Measurement Units	W, dBm, A
AD Converter	24 Bit
Analog Amplifier Bandwidth	10 Hz
Update Rate	10 Hz
Remote Interface	USB 2.0
Power Supply	External: 5 V DC via USB
Dimensions
Overall Sensor Dimensions	Ø45 mm x 30.5 mm (1.77" x 1.20")
USB Housing Dimensions (Including Plug)	65 mm x 20 mm x 10 mm (2.60" x 0.80" x 0.40")
Cable Length	1.5 m
Weight	0.2 kg	0.2 kg
Mounting
Aperture Thread	Removable Adapter Plate with External SM1 (1.035"-40) Thread
Post Mounting	8-32 and M4 Taps
Compatible Fiber Adapter Item #'s	S120-FC (Included) S120-APC, S120-SMA, S120-ST, S120-SC, S120-LC (Not Included)

The maximum error that may appear during calibration taking the tolerances of performance for all equipment into account.
The appropriate range is chosen internally by the power meter to achieve the best accuracy. Automatic ranging can be turned off.

USB Power Meter with Thermal Sensors

Item #	PM16-401	PM16-405	PM15-425
Detector Type	Thermal Surface Absorber (Thermopile) with Background Compensation	Thermal Surface Absorber (Thermopile)
Wavelength Range	190 nm - 20 µm
Optical Power Measurement Range	10 µW - 1 W	100 µW - 5 W	2 mW - 10 W
Max Average Optical Power Density	500 W/cm²	1.5 kW/cm²
Max Pulse Energy Density	0.2 J/cm² (1 µs Pulse), 2 J/cm² (1 ms Pulse)	0.3 J/cm² (1 ns Pulse), 5 J/cm² (1 ms Pulse)	0.3 J/cm² (1 ns Pulse), 5 J/cm² (1 ms Pulse)
Max Intermittent Power^a	3 W	-	20 W
Linearity	±0.5%
Optical Power Resolution^b	1 µW	5 µW	100 µW
Measurement Uncertainty^c (Calibration Uncertainty)	±3% @ 1064 nm ±5% @ 190 nm - 10.6 µm	±3% @ 1064 nm ±5% @ 250 nm - 17 µm
Response Time^d	1.1 s	1.1 s	0.6 s
Optical Coating	Black Broadband Coating	High Power Broadband Coating
Sensor Aperture	Ø10 mm	Ø10 mm	Ø25.4 mm
Sensor Active Area	10 mm x 10 mm	10 mm x 10 mm	Ø27 mm
Distance to Detector^e	3 mm	5 mm	4.6 mm
Active Area Uniformity	±1% (Beam Diameter >1 mm)
Cooling	Convection (Passive)
Temperature Sensor (In Sensor Head)	NTC Thermistor
Power Meter Electronics Properties
Analog Measurement Ranges^b	1.6 mV, 25 mV, 400 mV	1.6 mV, 25 mV, 400 mV	2.56 mV, 16 mV, 100 mV
Measurement Units	W, dBm, V
AD Converter	24 Bit
Analog Amplifier Bandwidth	10 Hz
Update Rate	10 Hz
Remote Interface	USB 2.0, Type-A Connector
Power Supply	External: 5 V DC via USB
Dimensions
Dimensions of the Sensor Head	43.0 mm x 33.0 mm x 15 mm (1.69" x 1.30" x 0.59")	40.6 mm x 40.6 mm x 16.0 mm (1.60" x 1.60" x 0.63")	50.8 mm x 50.8 mm x 35.0 mm (2.00" x 2.00" x 1.38")
USB Housing Dimensions (Including Plug)	65.0 mm x 20.0 mm x 10.0 mm (2.56" x 0.79" x 0.39")
Cable Length	1.5 m
Weight	0.07 kg	0.10 kg	0.22 kg
Mounting
Aperture Thread^f	Externally SM1-Threaded Adapter for Mounting Ø1" Lens Tubes and Fiber Adapters	Internally SM05-Threaded Aperture Externally SM1-Threaded Adapter for Mounting Ø1" Lens Tubes and Fiber Adapters	Internally SM1-Threaded Aperture External SM1-Threaded Adapter for Mounting Ø1" Lens Tubes and Fiber Adapters
Post Mounting	Ø1/2" Post via Universal 8-32 & M4 Tap (Post Not Included)
Cage Compatibility	N/A	30 mm Cage Systems via Two 4-40 Tapped Holes; Two Ø6 mm Through Holes for ER Series Rods	N/A
Compatible Fiber Adapter Item #'s	S120-FC, S120-APC, S120-SMA, S120-ST,S120-SC, S120-LC (Not Included)

Under conditions of intermittent use, with twenty-minute maximum exposure time for the S401C and two minute maximum exposure time for the S425C. The S405C saturates for optical input powers >5 W.
Measurement taken with the legacy PM200 console for the S401C and the PM400 console for the S405C and S435C. In all cases, the acceleration circuit was switched off. Resolution performance will be similar with our other power meter consoles.
Measurement uncertainty during calibration at the specified wavelengths for a beam diameter > 1 mm. The ±3% specification was determined by laser calibration, and the ±5% specification was determined through spectral calibration, in which values were interpolated using the laser calibration data and the absorption curve for the absorber. Calibration can be performed at 10.6 µm upon request.
Typical Natural Response Time (0 - 95%)
Distance is measured from the detector to the front face of the housing.
SM1 (1.035"-40) Threading; SM05 (0.535"-40) Threading

Compatible Power Meters

PM100A Analog Power and Energy Meter Console
PM100D Digital Power and Energy Meter Console
PM101 Series Power Meter Interfaces with External Readout (Version 2.0 or Later)
PM102 Series Power Meter Interfaces with External Readout (Version 2.1 or Later)
PM100USB USB Interface Digital Power and Energy Meter
PM400 Capacitive Touchscreen Power and Energy Meter Console
PM160, PM160T, and PM160T-HP Wireless Handheld Power Meters with Bluetooth^® Technology
PM16 Series Compact USB Power Meters

The Optical Power Monitor software is not compatible with the PM320E Benchtop Power Meter.

Optical Power Monitor

The Optical Power Monitor GUI software features power measurement, readout from up to eight power meters, and remote wireless operation.

For details on specific software features, please see the user manual, which can be downloaded here.

Users interested in the legacy Power Meter Software can find it by visiting the software page here.

The PM101 Series Power Meters are only compatible with version 2.0 or later. The PM102 Series Power Meters are only compatible with version 2.1 or later.

Optical Power Monitor GUI Software for Touchscreen, Handheld, and USB-Interface Power Meters

Features

Operate up to Eight Power Meters Simultaneously
Record and Analyze Measurements in Real Time
Intuitive Analog Display and Graphing Modes
Configurable Long-Term Data Logging
Also Supports Position Measurements with Thermal Position & Power Sensors
Compatible with USB and Bluetooth^® Connections

The Optical Power Monitor software GUI enables seamless control of up to eight power meters that are connected via USB, RS232, or Bluetooth^® wireless technology^a. The latest software, firmware, drivers, and utilities for these power meters can be downloaded here.

Multiple data measurement and analysis functions are integrated into the GUI package. The interface offers a user-friendly design with minimal use of color and low brightness that is ideal use in dark lab environments while wearing laser safety glasses. Measured data can be displayed in real time as a simulated analog needle, digital values, line graph, or bar graph. Continuously logged and short-term measurements can be recorded for data viewing and analysis at a later point. A built-in statistics mode analyzes measured data and continuously updates to reflect new measurements within the pre-determined measurement period. Beam position measurements are also supported when used with our thermal position & power sensors.

The Optical Power Monitor software package installs the GUI, which then can be used to control the touchscreen, handheld, or USB-interface power meters. Firmware updates for supported power meters are also available. Programming examples and drivers for interfacing with our power and energy meter consoles using LabVIEW, C/C++, Visual C#, and Python are installed with the software; refer to the manual for details.

Please note that the Optical Power Monitor Software uses different drivers than the Power Meter Utilities Software and Thorlabs recommends using the new driver TLPM.dll. For users who wish to use the legacy Power Meter Software or use custom software designed using the older PM100D.dll driver, a Power Meter Driver Switcher program is included for easy swapping of the installed driver between the two versions.

a. The PM160, PM160T, and PM160T-HP power meters are equipped with Bluetooth^® connections.

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Power Measurement Mode: Set up and configure up to eight power meters.

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Power Tuning Mode: Simulated analog needle and digital measurement value provided. Delta Mode, enabled above, shows the fluctuation range during the measurement period.

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Power Statistics Mode: Calculate numerical statistics for a pre-determined measurement period. The panel displays the analyzed values in a bar graph and the results as numerical values.

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Position Tuning Mode: Tuning mode can be used with a thermal position & power sensor to aid in beam alignment.

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Position Statistics Mode: Statistics mode also provides aggregate information for thermal position & power sensors.

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Data Logging: Enable long-term measurement and simultaneous recording from up to eight power meters. Save data as .csv files for later processing while measurement results are displayed in a graph in real time.

Pulsed Laser Emission: Power and Energy Calculations

Click above to download the full report.

Determining whether emission from a pulsed laser is compatible with a device or application can require referencing parameters that are not supplied by the laser's manufacturer. When this is the case, the necessary parameters can typically be calculated from the available information. Calculating peak pulse power, average power, pulse energy, and related parameters can be necessary to achieve desired outcomes including:

Protecting biological samples from harm.
Measuring the pulsed laser emission without damaging photodetectors and other sensors.
Exciting fluorescence and non-linear effects in materials.

Pulsed laser radiation parameters are illustrated in Figure 1 and described in the table. For quick reference, a list of equations are provided below. The document available for download provides this information, as well as an introduction to pulsed laser emission, an overview of relationships among the different parameters, and guidance for applying the calculations.

Equations:
Period and repetition rate are reciprocal:		and
Pulse energy calculated from average power:
Average power calculated from pulse energy:
Peak pulse power estimated from pulse energy:
Peak power and average power calculated from each other:
	and
Peak power calculated from average power and duty cycle*:
	*Duty cycle () is the fraction of time during which there is laser pulse emission.

Click to Enlarge

Figure 1: Parameters used to describe pulsed laser emission are indicated in the plot (above) and described in the table (below). Pulse energy (E) is the shaded area under the pulse curve. Pulse energy is, equivalently, the area of the diagonally hashed region.

Parameter	Symbol	Units
Pulse Energy	E	Joules [J]	A measure of one pulse's total emission, which is the only light emitted by the laser over the entire period. The pulse energy equals the shaded area, which is equivalent to the area covered by diagonal hash marks.
Period	Δt	Seconds [s]	The amount of time between the start of one pulse and the start of the next.
Average Power	P_avg	Watts [W]	The height on the optical power axis, if the energy emitted by the pulse were uniformly spread over the entire period.
Instantaneous Power	P	Watts [W]	The optical power at a single, specific point in time.
Peak Power	P_peak	Watts [W]	The maximum instantaneous optical power output by the laser.
Pulse Width		Seconds [s]	A measure of the time between the beginning and end of the pulse, typically based on the full width half maximum (FWHM) of the pulse shape. Also called pulse duration.
Repetition Rate	f_rep	Hertz [Hz]	The frequency with which pulses are emitted. Equal to the reciprocal of the period.

Example Calculation:

Is it safe to use a detector with a specified maximum peak optical input power of 75 mW to measure the following pulsed laser emission?

Average Power: 1 mW
Repetition Rate: 85 MHz
Pulse Width: 10 fs

The energy per pulse:

seems low, but the peak pulse power is:

It is not safe to use the detector to measure this pulsed laser emission, since the peak power of the pulses is >5 orders of magnitude higher than the detector's maximum peak optical input power.

Posted Comments:

Bryn Parry (posted 2020-07-21 16:17:10.763)

Hi, do you provide software for your USB power meters which is Linux compatible? Specifically I was hoping to run it on a Raspberry Pi 4.

MKiess (posted 2020-07-22 08:38:24.0)

Hello, Thank you very much for your inquiry. We have appropriate drivers for Ubuntu for the optical power monitor software. I have contacted you directly to discuss further details.

Patrick Au (posted 2020-06-30 14:37:08.677)

Would be great if they were also compatible with the Mac OS, or can be interfaced via Python drivers. thanks!

wskopalik (posted 2020-07-02 05:58:37.0)

This is a response from Wolfgang at Thorlabs. Thank you very much for your inquiry! Unfortunately, we don't offer Mac OS support for the PM16 series. We have a wrapper file for the driver and a sample code so the PM16 devices can be used in Python. These are however based on the Windows driver and only work on a Windows system. These files are included in the latest version of the power meter software. I will contact you directly to provide further assistance.

Jing Hou (posted 2019-12-22 19:00:47.313)

I CAN'T download the software via the school net, could you send me an installment package?

wskopalik (posted 2019-12-23 06:53:56.0)

This is a response from Wolfgang at Thorlabs. Thank you for your inquiry! I will contact you directly so we can find a way to send the software to you.

sri g (posted 2019-12-16 09:31:49.203)

Hi for PM16-425 - USB Power Meter, I cannot measure any power from the device even by just using a white light source. Though when I tried an UV source and fixed the wavelength around 420, it shows some power output. Can you tell me, what could be possible issue with the device.

nreusch (posted 2019-12-18 04:36:51.0)

This is a response from Nicola at Thorlabs. Thank you for reporting this issue. As long as you use a light source in between 2 mW and 10 W in e.g. the visible wavelength range, you should be able to detect the optical power. Are you able to perform the zeroing properly? I will contact you directly to resolve the issue.

Jeff Chen (posted 2019-07-18 09:17:32.387)

Hi, I'd like to ask if the PM16-121 can be calibrated NIST traceable power versus wavelength?

wskopalik (posted 2019-07-22 10:56:00.0)

This is a response from Wolfgang at Thorlabs. Thank you for your inquiry! Each sensor head is individually calibrated and is shipped with a NIST- and PTB-traceable calibration certificate. For the calibration, the responsivity of the sensor head is measured over the whole wavelength range. The responsivity is the ratio of the current generated by the photodiode and the incident power in this case. I will contact you directly to provide further information.

Daniel Gagnon (posted 2019-05-24 19:27:35.55)

Hi this is for PM16-121. I'd like to know if it's possible for me to gain access to the calibration data for my specific unit?

MKiess (posted 2019-05-31 06:22:47.0)

This is a response from Michael at Thorlabs. Thank you very much for your inquiry. Yes, it is possible to get the calibration data for your specific sensor. I will contact you directly and be happy to send you the data.

Patrick_Lee (posted 2019-02-13 17:58:48.567)

Hi for PM16-121 - USB Power Meter, possible to set integration time for calculating average power of pulse laser ?

wskopalik (posted 2019-02-21 05:27:14.0)

This is a response from Wolfgang at Thorlabs. Thank you very much for your inquiry! The internal integration time is unfortunately determined by the AD converter used in these sensors. It cannot be changed. So it depends mainly on the parameters of your laser (e.g. repetition rate, pulse duration) if the PM16-121 is suitable or not. In general, thermal power sensors are better suited for pulsed lasers due to their measurement principle. I will contact you directly so we can look for a good solution for your application.

itswonie (posted 2018-11-07 09:04:40.21)

There are some questions about "PM16-130" I already have a fluorescense light source which is connected to a microscope for optogenetic experiments and I would like to measure the light power. - Is it ok that I use the PM16-130 for this measurement? - Is software free for use? Please let me know. Thank you.

nreusch (posted 2018-11-15 07:10:26.0)

This is a response from Nicola at Thorlabs. Thank you for your inquiry! The PM16-130 is designed to be used to measure light in a wavelength range of 400-1100 nm and an optical power range between 500 pW up to 5 mW (without filter) or 500 mW (with filter). Do these features match to your light source? The software is available free of charge at https://www.thorlabs.com/software_pages/ViewSoftwarePage.cfm?Code=OPM. I will contact you directly to check whether you need any further assistance.

massimo (posted 2017-09-21 09:25:02.703)

As specified in the spec-sheet, the viewing target is removable. I've noticed that on the other side it is white. Can I assume it is reflective and for which wavelength? I'm asking this because I'm using the power meter in an integrating sphere with a non-monochromatic light and I was wondering if mounting the target the other way around would offer a reflectance similar to the one of the surface of the integrating sphere. Thanks

swick (posted 2017-10-05 03:41:20.0)

This is a response from Sebastian at Thorlabs. Thank you for the inquiry. The substrate material used for the viewing target is not precisely defined. It is some sort of hard plastic. Basically the reflectivity is not specified but should be better than for the fluorescing side. I will contact you directly for further discussion.

xiang.zhan (posted 2017-09-05 18:47:00.38)

Hi! I'm now selecting a suitable equipment to measure the intensity of my light source. The light source is a Xenon type, and I would use filters to generate 370-750nm wavelength range, which is a broadband.We have a uncalibrated spectrometer which can measure the relative light intensity with the wavelength (like a spectrum). I have three questions:1)if I would like to measure the absolute intensity, which equipment would you recommend? 2)Supposing that I have a PM16-401, as I understand,I have to enter a specific wavelength then get a intensity result in the software. Does the result represent the intensity at the wavelength I entered? Or it measures the total power? 3) For me it's also enough to get the overall intensity/power of the brandband, do you have a suitable equipment? Thanks!

wskopalik (posted 2017-09-07 10:01:24.0)

This is a response from Wolfgang at Thorlabs. Thank you for the inquiry. For a broadband light source thermal sensors such as the PM16-401 are a good choice. The PM16-401 has a flat absorption curve in your spectral range so the wavelength dependence is very low. You can see a diagram of this curve on the website. The wavelength you enter will determine the calibration factor which is used for the conversion of the sensor signal to a power value. Due to the flat absorption in this range you can simply enter a value in the middle of your range e.g. 560nm. Powermeter sensors cannot separate the light of different wavelengths, they can only measure the total power. So the power value will represents the total power of the incoming beam. I have also contacted you directly to provide further assistance.

bjorn.agnarsson (posted 2017-08-28 10:20:39.153)

I was trying to use the PM16-140 to evaluate my microscope Mercury lightsource spectrum and noticed that as I measure light power as a function of wavelength, the response is very linear, dropping from high power to low with increasing wavelength. This is not normal, as peaks should appear in accordance with the emission spectra of the lightsource. Am I missing something here? Can the power meter maybe not be used to measure absolute power, only relative power changes. I am very confused... All help, would be much appreciated. Best regards, Björn

swick (posted 2017-08-29 04:56:41.0)

This is a response from Sebastian at Thorlabs. Thank you for the inquiry. The PM16-140 is based on an Integrating Sphere equipped with a Photodiode. It can be used to measure the absolute optical power traceable to a National Standard. The responsivity vs wavelength is not constant for this sensor. When measuring broadband sources the results have to be corrected in view of the light sources' spectrum. In our Power Meter Consoles PM400 and PM200 the spectral correction can be applied directly in the console. In case the spectrum is known it can be loaded into the console and the displayed values will be automatically corrected. Unfortunately, in our PM16-Series this feature is not implemented. I will contact you directly for assistance.

stijn.moonen (posted 2017-05-03 08:33:48.717)

Hi, currently I am using a PM16-140 power meter. So far I am very happy about its performance. Now I wat to extend my measurement and perform the measurement at a higher temperature. Thus I am curious about the operating temperature of this specific power meter. Can you help me with this? Best regards, Stijn Moonen

swick (posted 2017-05-05 03:26:18.0)

This is a response from Sebastian at Thorlabs. Thank you very much for the feedback. The operating temperature of the power meter consoles and sensors is 0-40°C, while calibration of the sensors is valid for 23-25°C. Outside of 23-25°C additional uncertainty will occur. You can expect the uncertainty to be 0.1%/°C at most wavelengths. At the sides of the wavelength ranges (especially above 1600nm) the uncertainty could raise to 1%/°C. The power meter consoles and sensors could be damaged above 70°C.

Ville.kontturi (posted 2017-04-24 10:33:01.24)

Dear Mr/Mrs, How many measurements PM16-120 can perform in one second? Best regards, Ville Kontturi

swick (posted 2017-04-26 03:12:29.0)

This is a response from Sebastian at Thorlabs. Thank you for the inquiry. The number of measurements in one second depends on the quality of the USB connection and the operating system of the PC. In our Optical Power Meter Utility the min. interval time PM16-Series is 0.1s.

ngaber (posted 2016-01-22 18:05:24.087)

Dear Sir, We purchased the sensor PM16-401 and found in the datasheet the warning that it is sensitive to electrostatic discharges. Isn't it shielded? what are the precautions during handling? Thanks in advance

shallwig (posted 2016-01-26 02:05:17.0)

This is a response from Stefan at Thorlabs. Thank you very much for your inquiry, the precautions and warnings mentioned in the spec sheet were accidently copied from data sheets for photodiode sensors. The units are shielded and there is no special precaution necessary during handling. I am sorry for the confusion, I will contact you directly to check if you have any further questions.

loic.morvan (posted 2015-12-07 10:56:19.357)

Hello, will the software be compatible with a eWindows 10 Home 64" environment ? Many thanks by advance, best regards, Loïc

shallwig (posted 2015-12-07 08:42:37.0)

This is a response from Stefan at Thorlabs. Thank you very much for your inquiry. The software for our power meter units is compatible up to Windows 10 and down compatible to Windows XP. I will contact you directly to check any further questions.

user (posted 2015-06-05 17:16:10.307)

If the new sensors are wireless, we are more happy.

shallwig (posted 2015-06-05 07:21:04.0)

This is a response from Stefan at Thorlabs. Thank you very much for your feedback. At the moment the only wireless power meter we offer can be found here: http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_ID=7233&pn=PM160 There are two different sensors available so far, one thermal and one photodiode sensor. If you have any questions about these power meters or any other please feel free also to contact us directly at europe@thorlabs.com

Compact USB Power Meters with Standard Photodiode Sensors

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Item #^a	PM16-120	PM16-121	PM16-122
Detector Type	Silicon Photodiode		Germanium Photodiode
Wavelength Range	400 - 1100 nm		700 - 1800 nm
Optical Power Range	50 nW - 50 mW	500 nW - 500 mW	50 nW - 40 mW
Aperture Size	Ø9.5 mm
Resolution	<1 nW	<10 nW	<2 nW
ND Filter	Reflective ND (OD1)	Reflective ND (OD2)	Absorptive ND (Schott NG9)
Sensor Housing Dimensions	Ø30.5 mm x 12.7 mm (1.2" x 0.50")
Post Mounting	8-32 and M4 Combined Tap

For complete power meter specifications, see the Specs tab.

For General Purpose Optical Power Measurements
- 400 - 1100 nm for Silicon (Si)
- 700 - 1800 nm for Germanium (Ge)
Integrated Viewing Target for Easy Sensor Alignment
Ø9.5 mm Sensor Aperture
Protective Cap Included

These USB Power Meters with standard photodiode sensors are ideal for measuring low-power coherent and incoherent sources with wavelengths from 400 to 1100 nm (Si photodiode) or 700 to 1800 nm (Ge photodiode). The NIST-traceable, calibrated sensors features a large Ø9.5 mm active area and an integrated annular viewing target surrounding the input aperture that absorbs wavelengths from 400 to 640 nm and 800 to 1700 nm.

The front face of the housing is externally SM1 (1.035"-40) threaded for compatibility with Thorlabs’ Ø1" lens tubes and other accessories, providing a convenient way to mount external optics, fiber adapters (sold below), filters, and apertures. A combined 8-32- and M4-threaded tap on the side of the housing accepts both metric and imperial posts.

Thorlabs offers a recalibration service for these products, which can be ordered below (see Item # CAL1 for Si sensors and Item # CAL2 for Ge sensors).

Compact USB Power Meter with Slim Photodiode Sensor

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Item #^a	PM16-130
Detector Type	Silicon Photodiode
Wavelength Range	400 - 1100 nm
Optical Power Range (with Filter)	500 pW - 5 mW (Up to 500 mW)
Aperture Size	Ø9.5 mm
Resolution	<100 pW (10 nW with Filter)
ND Filter	Reflective ND (OD2)
Housing Dimensions	150.0 mm x 19.0 mm x 10.0 mm (5.91" x 0.75" x 0.39") 5 mm Thickness on Sensor Side
Post Mounting	8-32 and M4 Taps

For complete power meter specifications, see the Specs tab.

For Optical Power Measurements in Tight Spaces
- Wavelength Range: 400 - 1100 nm
- Optical Power Range: 500 pW - 5 mW (up to 500 mW with ND Filter)
Position of Included Slideable ND Filter Automatically Detected for Accurate Power Measurements
Very Slim Design: Ø5 mm Thin on Sensor Side
Ø9.5 mm Sensor Aperture
Optional SM1A29 Adapter with VIS/IR Target and External SM1 Threads (More Details)
Optional FBSM Mount with VIS/IR Target for FiberBench Systems (More Details)

The PM16-130 Compact USB Power Meter with Slim Silicon Photodiode Sensor is designed for optical source power measurements in locations where space and accessibility are at a premium. The 5 mm thin sensor end can fit between closely spaced optics, cage systems, and other arrangements where standard power meters may not fit. The NIST-traceable, calibrated sensors also feature a large Ø9.5 mm sensor aperture and slideable neutral density filter for dual power ranges in one compact device.

The externally SM1-threaded (1.035"-40) SM1A29 adapter, available separately, can be attached by two setscrews to the sensor head to mount fiber adapters (sold below), light shields, filters or any other SM1-threaded (1.035"-40) mechanics or optics. The FBSM Mount allows our S130 series power sensors to be mounted vertically into FiberBench systems for stable mounting with a minimal footprint.

Thorlabs offers a recalibration service for these products, which can be ordered below (see Item # CAL-S130).

Compact USB Power Meters with Integrating Sphere Sensors

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Item #^a	PM16-140	PM16-144
Detector Type	Integrating Sphere (Silicon Photodiode)	Integrating Sphere (InGaAs Photodiode)
Wavelength Range	350 - 1100 nm	800 - 1700 nm
Optical Power Range	1 µW - 500 mW
Aperture Size	Ø5 mm
Resolution	<1 nW
Integrating Sphere Material / Diameter	Zenith® PTFE Integrating Sphere / Ø1"
Sensor Housing Dimensions	Ø45 mm x 30.5 mm (1.77" x 1.20")
Post Mounting	8-32 and M4 Taps
Included Fiber Adapter	S120-FC for FC/PC and FC/APC Connectors

For complete power meter specifications, see the Specs tab.

For Beam-Shape- and Entrance-Angle-Independent Power Measurements
Integrating Sphere Design Acts as a Diffuser with Minimal Power Loss
Ø5 mm Input Aperture
Removable S120-FC Fiber Adapters (FC/PC and FC/APC) Included

These Compact USB Power Meters with Integrating Sphere Photodiode Sensors are an excellent choice for entrance-angle-independent power measurements of non-uniform, diverging, beam shapes. Integrating spheres are ideal for power measurements from fiber sources, as well as off-axis free space sources.

The integrating spheres feature Ø5 mm entrance apertures and externally SM1 (1.035"-40) threaded entrance ports. Because of the large active detector areas of these sensors, the included S120-FC fiber adapter can be used with FC/PC- or FC/APC-terminated fiber. Additional fiber adapters for other connector types are available below. NIST-traceable data is stored in the power meter for accurate power measurements.

Thorlabs offers a recalibration service for these products, which can be ordered below (see Item # CAL1 for Si sensors and Item # CAL2 for InGaAs sensors).

Compact USB Power Meters with Thermal Sensors

Click to Enlarge

Click to Enlarge
PM16-401 Thermal Sensor with Included Light Shield

For Broadband Optical Power Measurements from 10 µW to 20 W
S401C: Low-Drift and High-Resolution Measurements
- Active Background Compensation Implemented
- 29.4 mm (1.16") Long, Removable Light Shield Included
S405C: 5 µW Resolution and 1.5 kW/cm² Power Density
S425C: Ø25.4 mm Input Aperture and 10 W Maximum Optical Power

These theromopile-based sensors are ideal choices for measuring broadband spectra from amplified spontaneous emission (ASE) sources, light emitting diodes (LEDs), filament lamps, swept-wavelength lasers, and other sources. In addition, thermal power sensors do not saturate, which makes them well suited to measuring pulsed sources with high pulse peak powers or long-duration pulses. These thermal power sensors also exhibit low dependency on the angle and position of the incident light beam. They are preferred for applications that cannot tolerate the strong wavelength dependencies and/or saturation thresholds of photodiode sensors. However, thermal power sensors generally have lower power resolutions and longer response times.

All include an externally SM1-threaded (1.035"-40) adapter, with threading concentric with the input aperture. The adapters are useful for mounting Ø1" Lens Tubes and Fiber Adapters (available below). The PM16-405's aperture has internal SM05 (0.535"-40) threading that is directly compatible with SM05 lens tubes, and two 4-40 tapped holes and Ø6 mm through holes enable it to connect directly to Thorlabs' 30 mm Cage Systems. The PM16-425 features an aperture with internal SM1 threading that is directly compatible with SM1 lens tubes.

The PM16-401 and PM16-405 are well-suited to measuring low-power optical sources when high-resolution and high-sensitivity measurements are required. The PM16-401's sensor head performs active background compensation to provide low-drift measurements with 1 µW resolution. It is ideal for use with aligning and measuring Mid-IR Quantum Cascade Lasers (QCLs). The PM16-405's sensor head is compatible with higher optical power densities, while providing high 5 µW resolution. The PM16-425 has a fast <0.6 s response time and an easily removable heat sink which facilitate upgrading it or building the sensor into a custom setup. If replacing the heat sink, please note that the replacement must provide heat dissipation adequate for the application.

Thorlabs offers a recalibration service for these products, which can be ordered below (see Item # CAL-S200).

Item #^a	PM16-401	PM16-405	PM16-425
Sensor Image (Click the Image to Enlarge)
Detector Type	Thermal Surface Absorber (Thermopile) with Background Compensation	Thermal Surface Absorber (Thermopile)
Wavelength Range	190 nm - 20 µm
Optical Power Range	10 µW - 1 W (3 W^b)	100 µW - 5 W	2 mW - 10 W (20 W^b)
Max Optical Power Density	500 W/cm² (Avg.)	1.5 kW/cm² (Avg.)
Aperture Size	Ø10 mm (Ø0.39")	Ø10 mm (Ø0.39")	Ø25.4 mm (Ø1.00")
Resolution	1 µW	5 µW	100 µW
Sensor Coating	Black Broadband Coating	High Power Broadband
Sensor Housing Dimensions	43.0 mm x 33.0 mm x 15.0 mm (1.69" x 1.30" x 0.59")	40.6 mm x 40.6 mm x 16.0 mm (1.60" x 1.60" x 0.63")	50.8 mm x 50.8 mm x 35.0 mm (2.00" x 2.00" x 1.38")
Post Mounting	Universal 8-32 / M4 Taps (Post Not Included)	Universal 8-32 / M4 Taps (Post Not Included)	Universal 8-32 / M4 Taps (Post Not Included)
30 mm Cage Mounting	-	Two 4-40 Tapped Holes & Two Ø6 mm Through Holes	-
Aperture Threads	-	Internal SM05	Internal SM1
Removable Heat Sink	-	-	Yes
Accessories	Externally SM1-Threaded Adapter Light Shield, with Internal SM05 Threading	Externally SM1-Threaded Adapter	Externally SM1-Threaded Adapter

For complete power meter specifications, see the Specs tab.
Under conditions of intermittent use, with maximum exposure time of 20 minutes for the PM16-401 and 2 minutes for the PM16-425. The PM16-405 saturates for optical input powers >5 W.

Internally SM1-Threaded Fiber Adapters

These internally SM1-threaded (1.035"-40) adapters mate terminated fiber to any of our externally SM1-threaded components, including our photodiode power sensors, our thermal power sensors, and our photodetectors.

The APC adapter has two dimples in the front surface that allow it to be tightened with the SPW909 or SPW801 spanner wrench. The dimples do not go all the way through the disk so that the adapter can be used in light-tight applications when paired with SM1 lens tubes.

Please contact Tech Support if you are unsure if the adapter is mechanically compatible.

Item #	S120-FC	S120-APC^a	S120-SMA	S120-ST	S120-SC	S120-LC
Adapter Image (Click the Image to Enlarge)
Fiber Connector Type	FC/PC^b,c	FC/APC^c	SMA	ST/PC	SC/PC^d	LC/PC
Thread	Internal SM1 (1.035"-40)

The S120-APC is designed with a 4° mechanical angle to compensate for the refraction angle of the output beam.
In certain angle-independent applications, this adapter may also be used with FC/APC connectors.
This connector uses a wide key (2.2 mm).
In certain angle-independent applications, this adapter may also be used with SC/APC connectors.

Recalibration Services

Thorlabs offers calibration services for our optical power meters. To ensure accurate measurements, we recommend recalibrating the meters annually. Refer to the table below for the appropriate recalibration service Item # that corresponds to your power meter. Once the appropriate Item # is selected, enter the Part # and Serial # of the product that requires recalibration prior to selecting Add to Cart.

USB Power Meter Item #	Sensor Type	Recalibration Service Item #
PM16-120	Standard Photodiode with Si Sensor	CAL1
PM16-121	Standard Photodiode with Si Sensor	CAL1
PM16-122	Standard Photodiode with Ge Sensor	CAL2
PM16-130	Slim Photodiode with Si Sensor	CAL-S130
PM16-140	Integrating Sphere with Si Sensor	CAL1
PM16-144	Integrating Sphere with InGaAs Sensor	CAL2
PM16-401	Thermal Sensor	CAL-S200
PM16-405
PM16-425

Please Note: To ensure your item being returned for calibration is routed appropriately once it arrives at our facility, please do not ship it prior to being provided an RMA Number and return instructions by a member of our team.

View All »Matching Part Numbers

Compact USB Power Meters

Features

USB Power Meters with Standard Photodiode Sensors

USB Power Meter with Slim Photodiode Sensor

USB Power Meters with Integrating Sphere Sensor

USB Power Meter with Thermal Sensors

Compatible Power Meters

Optical Power Monitor

Optical Power Monitor GUI Software for Touchscreen, Handheld, and USB-Interface Power Meters

Features

Pulsed Laser Emission: Power and Energy Calculations

Compact USB Power Meters with Standard Photodiode Sensors

Compact USB Power Meter with Slim Photodiode Sensor

Compact USB Power Meters with Integrating Sphere Sensors

Compact USB Power Meters with Thermal Sensors

Internally SM1-Threaded Fiber Adapters

Recalibration Services