The influence of background power on the performance of an ideal bolometer

The effects of radiant power loading on the performance of an ideal bolometer are analysed. The operation of the bolometer is characterized in terms of dimensionless parameters which correspond to the temperature sensitivity of the thermometric material, the electrical bias point and the amount of optical power loading. Expressions are derived for the zero frequency NEP and responsivity. Examples are given for the case of a bolometer cooled to 100 mK and used for ground-based astronomical photometry at submillimetre wavelengths.