Van der Voort, G. F.
Optical Microscopy.  Encyclopedia of Condensed Matter Physics: 175-182 (2005).

Electrically calibrated detectors are in widespread use today; they are commercially available and are calibrated in the factory with a calibration lamp. They use either a thermocouple, a thermopile, or a bolometer. They operate at ambient temperature and are commonly used for solar/artificial lighting and for laser power measurements.