Is the size of the OPHIR Star Lite radiometer probe 1 cm^2? If yes, can we consider the radiant flux (W) displayed on the screen to be irradiance value (W/cm^2)? If not, when is it possible to consider the radiant flux (W) displayed on the screen to be irradiance value (W/cm^2); for instance if the surface which is in contact with the probe is of the size 1 cm^2?

Thanks!