Compare Model Drawings, CAD & Specs Availability Price
Lock-in Amp Detector, Pyroelectric, 100 nW - 100 mW, 8 mm



Built-in lock in amplifier to reduce noise and drift

The LIAD series Radiometers use a pyroelectric or photodiode sensor in conjunction with chopped CW or quasi CW radiation, using a digitally synthesized lock-in amplifier to reduce external noise to a minimum. When connected to a compatible optical power meter, you can measure a calibrated power at a very low power level.  To maintain calibration uncertainty and guarantee performance, we recommend annual recalibration.

Chopper Included

The signal is passed through the 18Hz chopper, included in the products, and the chopped signal is detected by the sensor. All signals not at this 18Hz frequency are suppressed. The chopper must be placed close to the signal source so as to eliminate radiation from an unwanted source.  There is a 1/4-20 hole on each side of the chopper housing, to allow a large number of mounting options.

Broad wavelength range from 0.15 to 12 um

Two models are offered. The photodiode based model LIAD-PD-300N covers between 200 and 1100 nm, while the pyroelectric detector based model LIAD-PY-100M covers between 0.15 and 12 um.

Power Measurement down to 300 fW

While LIAD-PY-100M can measure down to 100 nW, the minimum measurable power specification of LIAD-PD-300N is as low as 300 fW, lowest calibrated power measurement.

Capable of a Pulsed Source with 200 Hz or Higher Frequency

The LIAD series sensor has a response time 0-95% of approximately 3.5 seconds. It will not be able to respond to signals changing faster than this. Pulsed sources can be measured using the LIAD series detectors, and the output will represent the average power of the pulsed source. For reliable readings, the pulse rate of the source should exceed about 200 Hz.

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 LIAD Series sensors. For more detailed information about our power meters, please see our Optical Power Meter Guide.






Measurement Modes


Single Shot Energy

Track (Position + Stability)

Pulsed Power


Single Shot Energy

Track (Position)


Single Shot Energy

Track (Position + Stability)

Analog Bandwidth 15 Hz  15 Hz 15 Hz 
Data Storage Limited by USB memory size

843-R-USB: Via PMManager

843-R: None

Via PMManager
Measurement Rate per Second 15 15 15 
Trigger In/Out No No No
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.