Measuring laser power in the tens of kilowatts is not a simple task. As high-power laser systems continue to advance, industrial and defense applications increasingly require reliable ways to measure, monitor, and characterize laser beams at power levels that were once far beyond standard measurement setups.
The Ophir 70K-W Ultra-High Power Laser Sensor was designed for these demanding environments. This water-cooled calorimetric sensor measures laser beam power up to 70 kW continuously and up to 100 kW from short exposures of several seconds using Power-from-Pulse™ technology.
Why Ultra-High Laser Power Measurement Is So Challenging
High-power laser systems generate intense thermal loads, require robust beam handling, and often operate in environments where space, safety, and integration are critical considerations.
In many applications, the laser cannot remain on long enough for a traditional calorimetric sensor to reach its full response time. This is especially relevant in systems that emit the beam for only a few seconds, such as certain directed energy applications.
That is where Power-from-Pulse™ becomes especially valuable.
Power-from-Pulse™: Measuring More from Short Exposures
Calorimetric power sensors typically measure laser power by absorbing the beam, removing the resulting heat through a cooling system, and calculating power based on the water temperature rise and flow rate.
However, when exposure time is limited, the sensor may not have enough time to reach its full thermal response.
The Ophir 70K-W sensor addresses this challenge with Power-from-Pulse™, enabling power measurements from short laser exposures of just a few seconds. This expands the sensor’s measurement capability up to 100 kW for short-duration measurements, while maintaining continuous measurement capability up to 70 kW.
For users working with laser-based systems that operate in short bursts, this provides a more direct and practical way to measure ultra-high laser power.
Designed for Demanding Industrial and Defense Applications
The Ophir 70K-W sensor is built for flexibility and integration across a wide range of high-power laser applications, including:
- High-power fiber laser development and testing
- Industrial cutting and drilling
- Directed energy systems
- Ultra-high-power laser characterization
- System integration and automated test setups
Its lightweight design, multiple communication interfaces, and real-time monitoring output make it easier to integrate into both laboratory and field-oriented environments.
Flexible Cooling and Beam Orientation
The 70K-W sensor supports both tap water and deionized water cooling. For long-term use, DI water may help reduce issues related to mineral deposit buildup that can occur with tap water.
The sensor can also accommodate both vertical and horizontal beams, providing additional flexibility for different test configurations and system layouts.
Real-Time Laser Power Monitoring
In addition to calorimetric power measurement, the 70K-W includes a built-in photodiode that enables real-time monitoring of the laser signal.
The analog output can be configured through software to provide either:
- A DC voltage representing laser power
- Raw, uncalibrated photodiode voltage
This output can be used to monitor laser rise time, pulse duration, and stability in real time. For system developers, this can support instantaneous feedback, control, and deeper characterization of laser behavior during operation.
Built-In Safety for High-Power Environments
At ultra-high power levels, safety is essential. The Ophir 70K-W includes a built-in interlock output that can disable the laser in the event of a cooling system failure.
The sensor also provides exceptionally low back reflection of less than 0.5%, an important feature when working with high-power laser beams and sensitive optical systems.
How the 70K-W Sensor Works
The measurement process is based on a calorimetric design.
The incoming laser beam reaches a water-cooled reflecting cone, which deflects and spreads the beam toward cylindrical cooling coils. These coils feature a black absorptive coating that absorbs the laser energy. The resulting heat is removed by the cooling water flow.
Power is then calculated by measuring two key parameters:
- The water temperature rise
- The water flow rate
The software displays the main measurement parameters, including laser power, water flow rate, water temperature increase, and statistical measurement data. Users can also control measurement settings, including the Power-from-Pulse™ function, directly from the interface.
Key Specifications and Features
The Ophir 70K-W sensor offers:
- Power measurement from 2 kW to 70 kW continuously
- Measurement up to 100 kW from short exposures of several seconds
- 130 mm entrance aperture
- Support for collimated beams and diverging beams with numerical aperture up to 0.22
- Vertical and horizontal measurement orientations
- Response time of approximately 40 seconds for 0–99% reading
- Real-time laser power monitoring for rise time, stability, and pulse duration
- Lightweight design of approximately 40 kg without water
- Spectral range from 0.8 to 10.6 µm
- Multiple built-in communication interfaces
- Built-in interlock output for enhanced safety
- Back reflection of less than 0.5%
A Practical Solution for Ultra-High-Power Laser Measurement
As laser systems continue to reach higher power levels, measurement tools must keep pace. The Ophir 70K-W sensor combines continuous high-power measurement, short-exposure Power-from-Pulse™ capability, real-time monitoring, safety features, and flexible integration in a single water-cooled calorimetric sensor.
For industrial, research, and defense environments that require reliable ultra-high laser power measurement, the 70K-W provides a practical solution for measuring, monitoring, and characterizing high-power laser systems.
