Ariel | Laser Thermal Power Sensors | Power Sensors - Ophir
Ariel | Laser Thermal Power Sensors | Power Sensors - Ophir
Ariel | Laser Thermal Power Sensors | Power Sensors - Ophir


  • Measures up to 8000W
  • Compact and self-contained with built in display, battery, and Bluetooth communication
  • No Water Cooling
  • Dust proof, splash proof
  • Includes a detachable diffuser for high power density beams
  • Wavelengths: 440-550nm, 900-1100nm, 2.94μm, 10.6μm
  • High thermal capacity of 14KJ for uninterrupted consecutive measurements
  • Only 3 seconds to display measurement
  • Long battery life: more than 15 hours
  • Two measurement modes: short exposure ‘power-from-pulse’ and continuous
  • Supported by PC and iOS or Android applications

In ‘power-from-pulse’ mode, the Ariel measures high power industrial lasers of up to 8kW by measuring the energy of a short exposure to this power. The laser is set to deliver a pulse of from 0.05 to several seconds. The Ariel then measures the energy and duration of the laser pulse and calculates the power. In continuous mode, the Ariel measures up to 500W for as long as 20s, or up to 30W continuously. The Ariel is ideal for usage in tight spaces such as additive manufacturing chambers as well as for production process quality control and R&D.


  • LP2
  • Ø32mm
  • 440-550nm, 900-1100nm, 2.94μm, 10.6μm
  • 200mW-8kW
  • Up to 2.4kJ
  • LP2 absorber: 4% (<2200 nm), 10% (2940 nm), 25% (10.6 µm); With window: 5%; With Diffuser: 25%
  • 70 L x 70 W x 80 D (mm)
  • N.A.
  • N.A.
  • 3 s
  • N.A.
  • N.A.
  • 8kW
  • N.A.
  • CE, UKCA, China RoHS
Need help finding the right sensor? Try our Sensor Finder


When an accuracy spec is given, what exactly is meant?

The Ophir specification on accuracy is in general 2 sigma standard deviation. This means, for instance, that if we list the accuracy as +/-3%, this means that 95% of the sensors will be within this accuracy and 99% will be within +/-4%. For further information on accuracy see and

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How do you calculate the power and energy density of a laser beam?

If the power is P and the diameter of the beam is D then the power density is P /(.785 * D2) . If it is a pulsed laser and the energy is E, the repetition rate is R and the diameter is D then the power density is E*R/(.785 * D2), The energy density is E/(.785 * D2). The sensor finder will automatically calculate the power and energy density.

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Does the damage threshold depend on power level?

The damage threshold of thermal sensors does depend on the power level and not only the power density because the sensor disc itself gets hotter at high powers. For instance, the damage threshold of the Ophir broadband coating may be 50KW/cm2 at 10 Watts but only 10KW/cm2 at 300W. The Ophir specifications for damage threshold are always given for the highest power of use of a particular sensor, something which is not done by most other manufacturers. This should be taken into account when comparing specifications. The Sensor Finder takes the power level into consideration when calculating damage threshold.

 Watch the 'FAQ: Does damage threshold depend on power level?' video

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Do I need to recalibrate my instrument? How often must it be recalibrated?

Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

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Can a laser measurement depend on the distance from the laser to the sensor?

In theory, if a beam is completely parallel and fits within the aperture of a sensor, then it should make no difference at all what the distance is; it will be the same number of photons (ignoring absorption by the air, which is negligible except in the UV below 250nm). If, nevertheless, you do see such a distance dependence, there could be one of the following effects happening:

  • If you are using a thermal type power sensor, you might actually be measuring heat from the laser itself; when very close to the laser, the thermal sensor might be “feeling” the laser’s own heat. That would not, however, continue to have an effect at more than a few cm distance unless the light source is weak and the heat source is strong.
  • Beam geometry – The beam may not be parallel and may be diverging. Often, the lower intensity wings of the beam have greater divergence rate than the main portion of the beam. These may be missing the sensor's aperture as the distance increases. To check that you'd need to use a profiler, or perhaps a BeamTrack PPS (Power/Position/Size) sensor.
  • If you are measuring pulse energies with a diffuser-based pyroelectric sensor: Some users find that when they start with the sensor right up close to the laser and move it away, the readings drop sharply (typically by some 6%) over the first few cm. This is likely caused by multiple reflections between the diffuser and the laser device, which at the closest distance might be causing an incorrectly high reading. You should back off from the source by at least some 5cm, more if the beam is not too divergent.

Needless to say, it’s also important to be sure to have a steady setup; a sensor held by hand could easily be moved around involuntarily, which could cause partial or complete missing of the sensor’s aperture at increasing distance, particularly for an invisible beam.

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How do I set the Ariel to the 8KW range? I only see ranges up to 500W, but the specification says it can measure up to 8KW.

The Ariel has 2 power measurement modes: CW and Short Exposure.

  • In CW mode, it can measure from 200mW up to 500W (up to 30W continuously, and up to 500W intermittently – up to 20 seconds at a time for 500W). The power ranges available in this mode are 500W/ 80W/ 8W.
  • In Short Exposure mode, it can measure up to 8KW, from a short exposure to the high power (typically about 0.3 seconds for the maximum 8KW). The power ranges available in this mode are 8kW/ 800W/ 80W/ 8W. The Ariel does not need water cooling – and is therefore as small as it is - because it is exposed to the very high power beams for only these short “pulses”.

Detailed instructions for how to use the Ariel can be found in a video on our website.

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  • StarLab

    The StarLab application together with an Ophir meter turns your PC or laptop into a full-fledged laser power/energy meter. Supports most Ophir laser power/energy sensors. Up to 8 sensors can be displayed at once on one PC. By using the Ophir COM Object, you can control the device from your own application. Supports the Ariel, Centauri, StarBright, StarLite, Juno, Juno+, Juno-RS, Nova II, Vega, Pulsar-1/2/4, Quasar, EA-1 and IPM sensor devices.

  • StarViewer - Ariel

    StarViewer turns your Android based smartphone into a portable Ophir laser power/energy measurement monitor. It works with Ariel, Juno and Quasar interfaces.

    Note: When using StarViewer version 3.05, the minimum Ariel F/W version is 1.33.

  • Firmware - Ariel

    Embedded Software for Ariel

    Latest Ariel firmware (version 1.33)

    Use StarLab version 3.62 (and up) to upgrade the firmware of your device. Press Here for step-by-step instructions.


Ariel, Ultra-Compact "All in One" sensor for measuring high power industrial lasers up to 8KW. Ariel, Ultra-Compact "All in One" sensor for measuring high power industrial lasers up to 8KW.
Ariel All-in-One High Power Laser Sensor: How to Use Ariel All-in-One High Power Laser Sensor: How to Use Ariel All-in-One High Power Laser Sensor: How to Use

Learn how to use the Ariel, Ophir’s new ultra-compact "All in One" sensor for measuring high power industrial lasers up to 8KW.

How to Use the StarViewer Android App to Operate the Ariel How to Use the StarViewer Android App to Operate the Ariel How to Use the StarViewer Android App to Operate the Ariel

In this short video, you'll learn how to use the "StarViewer" Android App to operate the Ariel, Ophir’s new ultra-compact self-contained industrial power meter.

Webinar: Meet Ariel, laser power measurement solution in space constrained, humid & dusty places Webinar: Meet Ariel, laser power measurement solution in space constrained, humid & dusty places Webinar: Meet Ariel, laser power measurement solution in space constrained, humid & dusty places

Learn what our all-in-one high laser power sensor can do for you, and get an overview of how to interface with it and use it If you need to measure industrial high-power laser beams, in tight or inaccessible spaces (Additive Manufacturing chambers might be a good example) - you will want to learn more about Ophir's Ariel!

  • Compact, robust stand-alone device – fits in smallest spaces even in harsh industrial environments
  • Fast measurement time of only 3 s – saves valuable time in sensitive processes
  • No need for power cable or cooling – measurements can be taken even in enclosed chambers
  • Measures power from short exposure (“Power from Pulse” mode) to up to 8 kW – easy measurement in high power laser processes
  • Continuous power measurement up to 500 W for 20s – offers maximum flexibility in usage
  • Withstands high power densities – measures even small beams with high power
  • Offers different wavelength ranges – suits many applications

Designed for OEM and end-user applications in closed and confined spaces, such as additive manufacturing, metal cutting, and welding, the Ariel power meter is a robust, battery-powered device that requires no water or fan cooling and is small enough to fit in the palm of your hand. The system measures laser powers from 200mW to 8KW, and at a wide range of wavelengths, including 440-550nm green and blue lasers, increasingly popular in copper welding.


Tutorials and Articles

Laser Power Sensors introduction

As described in the general introduction, the thermopile sensor has a series of bimetallic junctions. A temperature difference between any two junctions causes a voltage to be formed between the two junctions. Since the junctions are in series and the «hot» junctions are always on the inner, hotter side, and the «cold» junctions are on the outer, cooler side, radial heat flow on the disc causes a voltage proportional to the power input. Laser power impinges on the center of the thermopile sensor disk (on the reverse side of the thermopile), flows radially and is cooled on the periphery. The array of thermocouples measures the temperature gradient, which is proportional to the incident or absorbed power. In principle, the reading is not dependent on the ambient temperature since only the temperature difference affects the voltage generated and the voltage difference depends only on the heat flow, not on the ambient temperature.


Common Reasons for Thermal Sensor Damage or Out of Tolerance Conditions

This document was created to assist our valued customers in the proper care and maintenance of Ophir thermal laser power sensors. The following information is for reference only. If you have any reason to believe that the sensor is no longer performing within the original specifications,we always recommend that you send it in for repair and/or recalibration by our trained technicians to bring the unit back to the proper NIST traceable standards. We believe that Ophir thermal sensors can be used for many years without any repairs when used with the proper laser optical setup. We hope that this document will enable you to also enjoy the long life and reliable results for which Ophir-Spiricon is known.


How to Properly Select a Laser Power or Energy Sensor

The selection of a sensor to accurately measure the power of a laser or energy of a pulsed laser can seem like a simple and easy procedure. However, many times the selection process is limited to choosing a sensor that only meets the range of power or energy to be measured, leaving out several other essential criteria of the laser specifications; that without their consideration, can allow the wrong sensor to be selected, the laser to be measured inaccurately and likely to cause the sensor to fail prematurely.

Watch Our Laser Measurement Video


Calibration Accuracy of Ophir’s High Power Sensors

An explanation of how we do this is provided below (A). In addition, a recent check of Ophir’s 5000W head by PTB in Germany shows excellent agreement between our calibration and their standards. The details of the correspondence between our sensor and their standard at powers up to 1400W is included here (B).

A. High Power Measurement Calibration Method and Estimated Accuracy of Models 5000W and 10K-W


How Much of the Power Sensor Aperture Can My Laser Fill Up?

The entire aperture senses power, so you can use the whole head. That said, a beam in the inner 50% of the surface area (about 70% of the diameter) is specified by Ophir to be uniform within +/-2%. The sensitivity around the edges might be a little less, but generally the sensitivity doesn’t vary by more than +/-2% over the entire aperture.


Effect of Ambient Conditions on Laser Measurements

We are often asked about the specified ranges of various ambient conditions (temperature, humidity, etc.) for Ophir instruments. In this article we will clarify the effects of these conditions on laser measurements, so you’ll be able to use your Ophir laser measurement instrument effectively.


How to Use Water Cooled Ophir Sensors

Ophir water cooled sensors are designed to measure high powers in a relatively compact package. In order for the sensor to operate properly, the water flow rate, temperature and temperature stability have to be in the right range. For best performance of the sensor, the water flow rate should be the recommended rate. If the user system is not able to reach the recommended rate, then the minimum rate can be used and the sensor will meet spec but there may be some degradation of response time and linearity... Read more...

Ophir Power/Energy Meter Calibration Procedure and Traceability/Error Analysis

This document discusses the interpretation and basis for stated measurement accuracy of Ophir Laser Power/Energy meters.
1. General Discussion
2. Combination of Errors and Total Error
3. Analysis of Power and Energy Calibration Errors
4. Detailed Analysis of Power and Energy Calibration Errors


Laser Measurements in Materials Processing: How and When They Absolutely, Positively Must Be Made

19th century British physicist and engineer William Thomson, 1st Baron Kelvin, was the first to say, “If you can’t measure it, you can’t improve it.” When applying this principle to improving laser-based processes, there are a variety of parameters that must be measured. Given the continuously rising power of laser systems in material processing, the requirements for measurement systems are more challenging than ever. Which technologies are available to measure high-power lasers? How often should they be measured? What measurements should be tracked? When this data is collected, what should be done with it? Read more...

How do I know what range, or scale, to set my power/energy meter to? And what happens if I go over range?

Each given range represents one level of gain of an internal amplifier. The electronics, as always, have a limited Dynamic Range. If the measured signal is too low, in other words near the bottom of the range, then it may be lost in the noise and the reading will be inaccurate and noisy. If it’s too high – there may be saturation issues. To give an instrument a usefully wide dynamic range, multiple scales or ranges are used. Switching from range to range can be automatic (“Autorange”), or manual. Autoranging simply starts automatically at the least sensitive range and works its way down the ranges, sampling the signal as it goes, till it finds a range at which the signal is properly detected. Note, by the way, that only in POWER mode is Autoranging available. If we are working in Single Shot Energy mode, there is no Autoranging – simply because when we are measuring a single pulse, the instrument has no opportunity to work its way down the ranges as in Power mode.


Types of power / Energy Laser Sensors General Introduction

Power and Single Shot Energy Sensors
Ophir provides two types of power sensors: Photodiode sensors and Thermal sensors. Photodiode sensors are used for low powers from picowatts up to hundreds of milliwatts and as high as 3W. Thermal sensors are for use from fractions of a milliwatt up to thousands of watts.
Thermal sensors can also measure single shot energy at pulse rates not exceeding one pulse every ~5s.

Repetitive Pulse Energy Sensors
For higher pulse rates, Ophir has pyroelectric energy sensors able to measure pulse rates up to tens of KHz. These are described in the energy sensor section, section 1.3.


5 Situations Where Laser Performance Measurement is Necessary

Measuring the performance of a laser has possible for a number of years and is accomplished with a variety of techniques. These electronic laser measurement solutions give the laser user more relevant, time-based data that shows trends in laser performance rather than single data points. While these solutions have provided laser users with the ability to present data in a simple and easy to understand manner, the application of the data still seems to be unclear to many laser users. Read more...

High power, cramped spaces – Measurement challenges in additive manufacturing

Laser-based additive manufacturing is transforming industrial processes and opening up new horizons in a variety of application areas. In the aerospace and automotive industries, for example, it makes it efficient to manufacture intricate parts according to lightweight construction principles; in medical technology, it has expanded the range of prostheses and orthoses; and in toolmaking, it shortens the time it takes to implement new requirements. Long since AM applications have attained a level of maturity that allows for series production – but when it comes to checking the laser Read more...

Evolution of Measurement Technology for Laser-Based Additive Manufacturing Systems

MKS Instruments recognized early on that measuring the laser beam in laser-based AM processes would become the key to efficient production. Four years ago, the company introduced the first measuring device that could assess – without any contact – the caustics of the laser beam on the building plane. This was followed by the launch of Ophir Ariel, an innovative power meter for AM applications. Then at Laser World of Photonics 2022 in Munich, the manufacturer introduced Ophir BeamPeek ™, an integrated measuring system that bundles the various measuring tasks into one robust Read more...


Customers that purchase the above items also consider the following items. Ophir-Spiricon meters and sensors include a standard manufacturers warranty for one year. Add a one year Extended Warranty to your meter or sensor, which includes one recalibration.
  • USB Cable for Ariel


    USB-A to USB-C cable (1 unit supplied with Ariel)

  • USB Power Supply


    Power Supply AC/DC 5V 2.1A with USB-A socket (1 unit supplied with Ariel)