Liquid Crystals having color play centered at different temperatures are arranged on metal coated and nonmetal coated dielectric substrates and used to monitor electromagnetic radiation. While both substrates respond to changes in ambient temperature conditions, the metallized substrate will also have temperature changes due to absorbed radiation. The temperature-dependent light scattering properties of the liquid crystals are used as both the temperature measuring mechanism and the indicating mechanism, with the difference between the temperature indications of the two substrates being a measure of the radiation. An experimental model that measures radiation of 1 to 15 mW/cm2 at 2.45 GHz is described.