radiometersbolometers

Radiometer-bolometers are instruments that measure electromagnetic radiation by converting radiant energy into an electrical signal. A bolometer is a type of radiometer within this family that uses thermal detection: incident radiation is absorbed by a weakly coupled absorber, causing a small rise in temperature. This temperature change is transduced by a sensor, such as a thermistor, a superconducting transition-edge sensor, or a kinetic inductance detector, into a measurable electrical signal.

Bolometers require thermal isolation and low heat capacity to achieve high sensitivity. They often operate at cryogenic temperatures to reduce thermal noise and drift. Types include resistive thermistor bolometers, semiconductor bolometers, superconducting bolometers (like TES), and kinetic inductance detectors, each with distinct readouts and temperature ranges.

Radiometer systems encompass a broader class of detectors and configurations. They can be broadband total-power radiometers that measure integrated power, or heterodyne and Dicke-switched radiometers that convert frequency bands into a stable signal for amplification. Detectors in radiometer systems can include diodes, thermopiles, or bolometers themselves.

Applications span astronomy (infrared, submillimeter, millimeter wavelengths), cosmic background studies, remote sensing, weather and climate monitoring, and laboratory radiometry. In practice, bolometers often serve as highly sensitive detectors within radiometer systems, particularly where low photon fluxes or broad spectral coverage are involved.