Fast antenna-coupled terahertz detectors based on uncooled thermoelements

We report on uncooled antenna-coupled thermoelements with a fast response time operating at 0.812 THz. Each sensor pixel consists of 8 thermocouples in series. As thermoelectric structure, a BiSb/Sb freestanding air-bridge is used, fabricated by micromachining. A thermal time constant as low as 22 µs and a NEP of 130 pW/Hz
^0.5
at 1 kHz modulation frequency is measured in air at room temperature. The integration capability of the thermocouple sensors enables cost-efficient large-scale detector arrays.