The RM9 series of radiometers are designed to 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. The signal is passed through the 18 Hz chopper and the chopped signal is detected by the sensor. All signals not at the 18 Hz frequency are suppressed.
The RM9 chopper and lock-in amplifier are able to provide the lowest noise and drift within the device. The sensor's power range is from 300 fW (femtowatt) to 300 nW (nanowatt). It has an 8 mm aperture and covers the spectral range from 0.2 µm to 1.1 µm. The series also features a wavelength range from UV to deep IR, including Terahetz. The output of the sensor is displayed on a standard Ophir meter or PC interface. The RM9 pyro option is not sensitive to background radiation.
For additional information on the RM9 series of radiometers, download the available datasheet.