Microheater multilayer interference to reduce thermal emission for low photon number luminescence measurement

Under low light conditions, high temperature measurements of luminescence are limited by the overlap of the thermal emission spectra and the luminescent emission spectra being measured. A solution to this is to have a heat source that can be designed not to emit in a certain wavelength range(s) by coating it with an interference multilayer. The multilayer effectively changes the emissivity of the heat source. Microheaters made from aluminum oxide platforms with platinum heating elements were coated with aluminum oxide and titanium oxide multilayers. This multilayer structure was used to measure the thermoluminescence of CaSO₄:Ce,Tb up to 420°C. They also showed a thermal emission background 800 times lower at 600°C than the same microheater with no multilayer structure.