High Absorption of Goldblack Film for a pyroelectric detector based on ultra-thin LiTaO 3 crystal

This letter reports on the performance of LiTaO 3 based pyroelectric single-element detectors coated with a nanos-tructured thin-film absorber consisting of the NiCr material as the sensor electrodes. Goldblack film have been proven to be an effective absorption layer for pyroelectric detectors. Improving the absorption can be achieved by adjusting the surface characteristics of goldblack film. Goldblack coatings are low-density amorphous deposits of gold that appear black in the visible and infrared regions of the electromagnetic spectrum. They have absorption close to unity for radiation in this range. Because of the delicate nature of the coatings, they are easily crushed or displaced by touch or even blasts of air, their use has not been extensively exploited but rather the process is re-invented every time a specific requirement appears. This is typified by our requirement to coat a small pixel pyroelectric detector.