thermal detector

instrument

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July 14, 2026

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A thermal detector is an instrument designed to measure radiant energy, particularly infrared radiation. These detectors operate by sensing an increase in temperature caused by the absorption of radiation. Common types include thermocouples, which generate a voltage when heated, and bolometers, which experience a change in electrical resistance with temperature fluctuations.1

While the term "radiometer" can refer to various devices, it is often associated with the Crookes radiometer, an early, less precise instrument. Modern thermal detectors are more accurate and are crucial in fields like manufacturing, scientific research, and medical practice for temperature measurement. Thermal analysis, a related technique, involves measuring a property of a substance while heat is applied, often monitoring temperature changes to understand decomposition mechanisms or for quantitative analysis.213

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spectroscopy
Infrared instrumentation
Thermal detection of infrared radiation is based on the conversion of a temperature change, resulting from such radiation falling on a suitable material, into a measurable signal. A Golay detector employs the reflection of light from a thermally distortable reflecting film onto a photoelectric cell,…
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Thermal detection of infrared radiation is based on the conversion of a temperature change, resulting from such radiation falling on a suitable material, into a measurable signal. A Golay detector employs the reflection of light from a thermally distortable reflecting film onto a photoelectric cell,…
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radiometer
…as Herschel’s thermometer, are called thermal detectors. Commonly used thermal detectors include the thermocouple, which produces a voltage when heated, and the bolometer, which undergoes a change in electrical resistance when heated. Devices that can, in principle, detect a singular quantum of radiant energy, such as Becquerel’s photographic plate, are…
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…as Herschel’s thermometer, are called thermal detectors. Commonly used thermal detectors include the thermocouple, which produces a voltage when heated, and the bolometer, which undergoes a change in electrical resistance when heated. Devices that can, in principle, detect a singular quantum of radiant energy, such as Becquerel’s photographic plate, are…
Read More