The temperature controller is optimised for use with standard NTC thermistors as they give the highest sensitivity to temperature change. Using a standard thermistor with a T25 of between 10k and 100k the temperature resolution of the controller is under 1mK.
The thermistor type and characteristics can be defined through the temperature controller setup user interface. The thermistor voltage is digitised using a high precision 24 bit A/D converter with a 1ppm/°C reference, so it’s very stable against internal and ambient temperature changes.
The absolute temperature accuracy is usually determined by the thermistor tolerance. The precision of temperature control of the QCL is affected by several factors, the main one being the thermal / mechanical proximity of the thermistor to the QCL device. With reasonable care 1mK can easily be achieved.