Laser Power Sensor Guide

Compatible Power Meters

Optical Power Meters like the 1918-R (shown above) can be used with Newport compatible laser power sensors

Optical Power Meters like the NOVA-II (shown above) can be used with Ophir compatible laser power sensors

Laser Energy Sensors

Thermopile Laser Power Sensors are capable of measuring average power for pulsed lasers as well as single shot energy for pulses spaced at least 5 seconds apart. For more advanced energy measurements we recommend Pyroelectric Laser Energy Sensors.

Accurate and Reliable Laser Power Measurement Solutions for 35 Years

For over 35 years, Newport has met the challenge to consistently provide accurate and reliable optical measurement solutions such as Laser Power Sensors. We offer a wide range of calibrated thermoplile laser power sensors for use with Newport or Ophir Optical Power Meters.

Thermopile Laser Power Sensor Basics

A Thermopile is an electronic device that converts themal energy into electrical energy. Thermopiles are composed of multiple thermocouples and generate a voltage proportional to a local temperature gradient. Thermopile based laser power sensors respond slowly to laser beam inputs but can handle high optical power making them suitable for measuring the average power of CW or pulsed lasers. For more information on Thermoplie based laser power sensors, please refer to our Thermopile Laser Power Sensor Technology Guide.

Selecting a Laser Power Sensor

Optical Power and Energy Meter Compatibility

Our Laser Power Sensors come with a DB15 connector and are calibrated for use with either Newport Brand optical power and energy meters like the 1918-R , 843-R , 1936-R and 2936-R , or for use with Ophir Brand optical power and energy meters like the NOVA-II and VEGA . Please refer to the brand compatibility tables below to choose a laser power sensor that will work with your Newport or Ophir Optical Power Meter.

Maximum Optical Power Requirements

In general, thermopile laser sensors can be divided into three power input ranges. High Sensitivity Thermopile Sensors are capible of measuring at µW levels, replacing photodiode sensors in some applications. Low to Medium Power General Purpose Thermopile Sensors are capable of measuring laser power in the mid mW to 500 W range. Water Cooled Thermopile Sensors are designed for very high power applications up to 5 kW. Please refer to the brand compatibility tables below to select the proper power range for your laser.

Beam Diameter at Sensor

The size of your laser beam at the sensor head is an important criteria for laser power sensor selection. This dimension will determine the appropriate sensor active diameter. It is preferred to use a thermopile sensor with an active diameter sufficient to contain the entire beam without the use of additional optics. You should chose a sensor active diameter that is between 10% and 30% larger than your beam diameter to allow for ease of beam alignment and positioning. You can select the active diameter, power range requirement, and power meter compatibility using the tables below. Popular active diameters include: 12mm, 17mm, 19mm, 25mm, 35mm, 50mm and 55mm.

Maximum Power Density

Themopile sensors can be damaged if their maximum power density rating is exceeded. For CW Lasers, Power Density = Beam Power (W) / (0.785 x Beam Diameter² (cm)). For example, a 100 W beam with a 2 mm diameter has a power density of 3.184 kW/cm². We recommend that you measure your beam in a place where it is not highly focused to reduce the power density, and choose a sensor with a damage threshold value rating that exceeds your maximum power density requirements by at least 65%.

Newport Power Meter Compatible Laser Power Sensors

	Active Diameter	Features and Benefits
919P Series Thermopile Sensors	9.5 - 65 mm	• Broadband flat spectral response from 0.19–11 µm • NIST-traceable calibration included • Insensitive to beam position • Compatible with the new 843-R power meter • Calibrated at 532, 1064, and 10600 nm (except for 919P-5kW-50)
High Sensitivity Thermopile Sensors	12mm	• Measures 1 µW to 3 W optical power • Compatible with Newport brand power meters • Broadband flat spectral response from 0.19–11 µm • Low thermal drift of 6 µW/C • Insensitive to beam position
General Purpose Thermopile Sensors	12mm 17mm 18mm 19mm 25mm 50mm 55mm	• Measure up to 500 W optical power • Compatible with Newport power meters • High damage threshold • Insensitive to beam position
Water Cooled 3 kW Thermopile Sensor, USB	100 mm	• Measure up to 3 kW optical power • Compatible with Newport power meters • USB for PC Connection w/o a power meter • Low sensitivity to cooling water temperature

Ophir Power Meter Compatible Laser Power Sensors

	Active Diameter	Features and Benefits
Low Power Thermopile Sensors	High Sensitivity Thermopile Sensors
	9.5mm 12mm	• Measure 30 µW to 12 W optical power • Compatible with Ophir power meters
	Low Power Thermopile Sensors
	16mm 17.5mm 26mm	• Measure up to 30 W optical power • Compatible with Ophir power meters
Medium Power Thermopile Sensors	17mm 26mm 35mm 50mm	• Measure up to 500 W optical power • Compatible with Ophir power meters • Sensor Body, Heatsink, or Fan Cooling
Water Cooled Thermopile Sensors	50mm	• Measure up to 5 kW optical power • Compatible with Ophir power meters • Water cooled