Precise measurements of optical power enable activities from fiber-optic communications to laser manufacturing and biomedical imaging-anything requiring a reliable source of light.
Currently different methods for calibrating optical power measurements are required for different light levels. Knowing the energy of each photon and the number of incident photons enables an extremely accurate determination of optical power. In order to use TES devices at higher optical power levels, the operating range needs to be extended. Comparing the change in the measured photon number as the input attenuator is adjusted allows the attenuator to be calibrated in place.
Since the ratio by which an attenuator reduces the power of a signal is independent of input power, measurements of attenuation made at the few-photon level should agree with those made at much higher intensities.
This means a TES-calibrated attenuator can be used to compare detectors, regardless of the optical power they are designed to operate at.