High-Efficiency Thermoelectric Sensor with Tungsten Absorber for Registration of Single Photons of the Extremely Ultraviolet Range

The results of computer modeling of heat propagation processes in a multilayer thermoelectric sensor after absorption of single photons of the extreme ultraviolet wavelength range are presented. The sensor consists from a W absorber, a La0.99Ce0.01B6 thermoelectric layer, a Mo heat sink, and an Al2O3 dielectric substrate. The optical spectra of tungsten are examined and it is found that a sensor with a W absorber can provide efficient optical coupling with photons of extreme ultraviolet wavelengths. The optimal thickness of the absorber that will provide effective absorption of photons in this region is determined. Computer simulation was performed using the three-dimensional matrix method based on the equation of heat propagation from a limited volume. The temporal dependences of the temperature of different areas of the sensor after absorption of single photons with wavelengths of 55.1, 32.627 and 27.71 nm (22.5, 38 and 44.7 eV) were studied. The obtained results allow calculating the signal/noise ratio of the sensor and determining the efficiency of recording an already absorbed photon. It has been proven that the system efficiency of a thermoelectric sensor with a tungsten absorber can exceed 90% when recording single photons in the extreme ultraviolet range.