Thermal methods of measuring power and energy are those in which radiant energy is absorbed and converted into heat, which generates a temperature rise in the absorber. The absorbed energy is then measured through a function that takes into account the temperature gradient between the hot area (where the laser strikes) and a cool area (where the generated heat is dissipated). This measurement can be done by means of thermocouples arrays (thermopile). The temperature difference will generate a voltage at the end of every single thermocouple and the resulting total voltage will be proportional to the incident power or energy.
Different cooling methods among convention, forced air and water are used depending on the maximum measurable power. Each thermal sensor is provided with certificate with NIST and PTB traceability. Thermal sensors can be provided with DB15 or with USB and RS-232 connectors (PC-plug option). Laser 2000 sells two series of head thermal sensors, the 10& 2o and BLINK series.