Overview of RM9-PD radiometer system (with chopper):

The RM9-PD radiometer system is a sensor and optical chopper system used to measure the power of very low level CW or quasi CW sources. The RM9-PD sensor has a photodiode element. The power range of the sensor is from 300fW (flying watt) to 300nW (nanowatt). It has a 10mm aperture and covers the spectral range from 0.2 µ m to 1.1 µ m. The system has an RMC1 chopper placed between the source and the RM9-PD sensor. (When installing the chopper, the side marked "THIS SIDE TOWARD SENSOR" should face the sensor.)

RM9-PD (with chopper) product drawing:

Main parameters：

Problem induction：

How to clean the sensor？

Use Umicore # 2 substrate cleaner, acetone or methanol to clean the absorber surface with a paper towel. Then dry the surface with another paper towel. Note that some absorbers (Pyro BB, 10K-W, 15K-W, 16K-W and 30K-W) cannot be cleaned in this way. On the contrary, only clean air or nitrogen is needed to blow off the dust. Do not touch these absorbers. In addition, HE sensors (such as 30 (150) A-HE-17) should not be cleaned with acetone.

Is it possible to measure the pulsed laser power with RM9？

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.

Is it possible to 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, the BNC synchronizer can be connected to the RM9 sensor, and the RM9 can be used directly with the laser source.