Infrared fluorescence ‘‘decay‐time’’ temperature sensor

The principle of the change in the ‘‘decay time’’ of the fluorescence of a small sample of neodymium in a glass matrix, excited by infrared radiation from a high‐power light emitting diode has been used in the construction of a fiber‐optic temperature sensor. Such a device is an inexpensive transducer and has demonstrated a fiber‐optic sensor not requiring referencing to the intensity of the exciting radiation.