Overview of RM9 thermal radiometer (with locking function):

User's Manual

RM9 radiometer is a sensor used to measure the power of low-level CW or quasi CW laser and light source. RM9 uses a pyroelectric sensor and a lock-in amplifier with an 18Hz chopper (excluding RMC1 or other choppers) to measure a wide range of radiation from 100nW to 100mW. It has an 8mm aperture and covers the spectral range from 0.15 μm to 12 μm.

RM9 Thermal Radiometer Drawing：

Main parameters:

Problem summary:

Can I use the RM9 sensor to measure an 18 Hz pulse source without a chopper?

If the source happens to be a pulse of 18 Hz, the chopper cannot be used because it will produce a beat signal of very low frequency. However, as long as the BNC synchronizer is connected to the RM9 sensor, the RM9 can be used directly with the laser source.

How to use RM9 radiometer to greatly improve the measurement accuracy?

RM9 is only sensitive to signals chopped at 18 Hz, so placing the chopper as close to the laser source as possible can greatly reduce stray light entering the chopper and being read as part of the signal.

The noise specification is based on a 10 second moving average and the power meter is set to the average of the measured values for better performance.

It is recommended to zero the sensor before use by disconnecting the BNC cable between the RM9 sensor and the chopper or closing the chopper.

Can RM9 be used to measure pulsed laser power?

Yes, but RM9 will measure average power, not energy. In addition, pulse rates below 50 Hz may generate additional noise. A pulse rate close to 18 Hz may cause beat problems.