Power Meters FAQ's

Thermal Laser Power Sensors



The various RM9 radiometer models are fully compatible with these meters/interfaces:

  • Vega / Nova II (firmware version 2.44 or higher)
  • Juno (1.31 or higher)
  • StarLite (1.26 or higher)
  • StarBright (1.18 or higher)

They are partially compatible with Ophir’s other meters (Nova, LaserStar, USBI, Pulsar, and Quasar). They will function properly with these devices, except with a narrower power range and with reduced accuracy; see specs for more details.


Typical choppers have the same type of surface on both faces: either metallic, low emissivity or black, high emissivity.
When blocking the laser beam, metallic surfaces will reflect or scatter a significant portion of the laser power which may result in stray reflections reaching the sensor.
Black surfaces solve this issue, but if the chopper is positioned close to the RM9 or RM9-THz sensor, they will pick up a thermal signal from the chopper blades.
Stray reflections and thermal signal from the blades can impair measurement accuracy.
Our chopper enjoys the best of both worlds. It has a black surface that should face the laser beam and a low emissivity surface that should face the sensor.