Compare Model Drawings, CAD & Specs Detector Type Spectral Range Maximum Measurable Power Sensor Size Maximum Power Density Availability Price
High Sensitivity 0.19 to 11 µm 3 W Ø9.5 mm 1 kW/cm²
General Purpose 0.19 to 11 µm 10 W Ø16 mm 28 kW/cm²
General Purpose 0.19 to 11 µm 4 W standalone (20 W with a heat sink) Ø12 mm 23 kW/cm²
General Purpose 0.19 to 11 µm 30 W Ø17.5 mm 20 kW/cm²
General Purpose 0.19 to 11 µm 35 W Ø50 mm 12 kW/cm²
High Energy Pulse 0.24 to 2.2 µm 50 W Ø17.5 mm 0.5 kW/cm²
General Purpose 0.19 to 11 µm 50 W Ø26 mm 12 kW/cm²
Fan Cooled 0.19 to 11 µm 150 W Ø26 mm 12 kW/cm²
Fan Cooled 0.19 to 11 µm 250 W Ø35 mm 10 kW/cm²
High Power 0.19 to 11 µm 5000 W Ø50 mm 3 kW/cm²
High Power 0.19 to 11 µm 600 W Ø65 mm 7 kW/cm²



Constant Responses over Broad Wavelength Range

The thermopile detector's response to the input laser beam is characterized by its absorption. We use two different types of coating in the sensor. The broadband BB type is employed in most of the models and has an excellent constant absorption throughout the responsive wavelength range.  Majority of the 919P series detectors employ the BB type, and you can measure light with the wavelength up to 11 µm. The PF type is employed in the mode 919P-050-18HP , which is specially designed for high energy density pulses.

Extensively Tested for Damage Threshold vs. Pulse Width

The 919P series thermopile detectors have been extensively tested for the damage threshold with a variety of lasers. You can trust our specifications and have your mind at ease.

Thermopile Sensor Physics

Thermopile optical power sensors are based on thermocouples. A thermocouple consists of two dissimilar metals connected in series. To detect radiation, one metal junction is typically blackened to absorb the radiation. The temperature rise of this junction with respect to another non-irradiated junction generates a voltage. This effect is the basis of all thermocouple temperature sensors. The thermocouple materials used in thermopiles are usually bismuth and antimony, which have a relatively high thermoelectric coefficient. An individual thermocouple typically produces a low output voltage, which results in a low detectivity and limits its use as a sensing device. So, one way to increase the output voltage is to connect many thermocouple junctions in series. All the “hot” junctions are placed close together to collect the radiation. The typical operation of a thermopile is shown above. The thermopile disc consists of a circular array of thermocouples. The optical radiation is absorbed by the disc generating the output voltage. The heat on the disc spreads radially across the thermopile on the reverse side of the disc where it is transferred to a heat sink. These devices are quite sensitive in the IR due to their broadband absorption. Due to the heating and cooling processes, the response time of a thermopile is quite slow, typically on the order of seconds. Due to this time constraint, thermopiles are used exclusively for measuring the power of CW or quasi-CW radiation sources. Please see our Thermopile Sensor Physics technical note for additional information.

Ideal for High Power Measurement

Newport’s 919P Thermopile Detector Series provide a full range of sensors to meet the power measurement needs for CW or pulsed lasers. They offer broadband, spectrally flat response, with the maximum power range up to 5000 Watts.

NIST Traceability

Each 919P thermopile sensor includes a DB15 connector and internal EEPROM for storing factory calibration data. Most sensors are calibrated at three different wavelengths at 532 nm, 1.064 µm, and 10.64 µm. Calibration of the thermopile detectors is recommended annually to assure NIST traceability.

Cross Reference Chart for Legacy 818P Series Thermopile Sensors

Legacy 818P Model Replacement 919P Model
818P-001-12, 818P-001-12NIR 919P-003-10
818P-015-19 919P-010-16
818P-010-12, 818P-020-12 919P-020-12
818P-030-19, 818P-015-17W, 818P-030-17W 919P-030-18
818P-040-55, 818P-040-50W, 818P-050-50W 919P-040-50
818P-015-18HP, 818P-030-18HP 919P-050-18HP
818P-040-25, 818P-050-17W 919P-050-26
818P-100-25, 818P-110-19, 818P-150-19 919P-150-26
818P-100-55, 818P-250-25, 818P-300-25 919P-250-35
818P-300-55, 818P-400-55, 818P-500-55 919P-600-65
818P-3KW-65, 818P-3KW-100 919P-5KW-50

Please note that the 919P Series Thermopile Sensors are intended to replace the 818P Series Sensor. Also note that both the series are incompatible with certain optical power meter models. The following table provides the recommended replacement 919P models for each 818P series model. Even though the recommended models have the closest specifications as the obsoleting ones, however, not identical. The user must carefully compare each specification.

Sensor Selection for Lasers

If you already own a laser from Newport and Spectra Physics, check our Optical Sensor Selection Guide to see the recommended sensor each laser product.

Flexible Fiber Adapters

Detector Model

Required Mounting Ring





919P-050-26, 919P-150-26




919P-020-12, 919P-050-18H

Fiber adapters not mountable

The 919P-SMA and 919P-FC fiber adapter can be used with most of the detector models. Remove the snout for Models 919P-003-10 and 919P-010-16 and directly mount the fiber adapters on the thread. In order to accommodate various aperture sizes, we provide adapter rings as well as the fiber adapters. Refer to the table for the corresponding adapter ring for each detector model. Note that certain models do not accept a fiber adapter.

Compatible Power Meters

Newport offers a comprehensive range of optical power meters from low cost, hand-held meters to the most advanced dual-channel benchtop meter available in the market. Presented here is a list of meters compatible with the 919P Series sensors. For more detailed information about our power meters, please see our Optical Power Meter Guide.








Measurement Modes


Peak-to-Peak Power

RMS Power


Single Shot Energy

Pulse Power


Single Shot Energy




Analog Bandwidth Up to 400 kHz 15 Hz  15 Hz 15 Hz 
Data Storage 250,000 pts internal Limited by USB memory size

843-R-USB: Via PMManager

843-R: None

Via PMManager
Measurement Rate per Second 10,000 15 15 15 
Trigger In/Out
Computer Interface





843-R-USB: USB

843-R: None

Additionally, please refer to Newport Power Meter and Detector Legacy and Compatibility for a complete list of meters that are compatible with this model.