1 Answers
Thermopile laser sensors are used for measuring laser power from a few µW to several W. The incoming radiation of the laser is converted into heat energy at the surface. This heat input produces a temperature gradient across the sensor. Making use of the thermoelectric effect a voltage is generated by this temperature gradient. Since the voltage is directly proportional to the incoming radiation, it can be directly related to the irradiation power.
Unlike photodiodes, thermopile sensors can be used for a broad spectrum of wavelengths ranging from UV to MIR. Further, photodiodes are reverse biased and saturate for optical powers above a certain value , making thermopile sensors suitable for high power measurements.
Pyroelectric sensor and calorimeter are commonly used for measuring the energy of laser pulses. Pyroelectric sensor can measure low to medium energies and are prone to microphonic effects. Calorimeters are capable of measuring high energies but have large response times.