A thermal imaging system based on the PrCl3 quantum counter

Ambient−temperature thermal background limited performance has been obtained for a thermal imaging system based on the PrCl3 quantum counter. The principal ’’noise’’ source in the PrCl3 quantum counter is shown to be a pump−induced emission characterized by a radiative lifetime of less than 50 nsec. Using the principle of temporal discrimination for the reduction of noise, a contrast of ∼40% was measured for a temperature difference of ∼5 °C above ambient temperature (23 °C).