Noise characterization of patch antenna THz photodetectors

• Published in: Applied physics letters Vol. 113; no. 16
• Main Authors: Palaferri, D., Todorov, Y., Gacemi, D., Barbieri, S., Li, L. H., Davies, A. G., Linfield, E. H., Sirtori, C.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 15-10-2018
• Subjects: Applied physics; Engineering Sciences; Frequency response; Noise; Optics; Patch antennas; Photometers; Photonic; Photonics; Quantum wells; Substrates; Variation; Electronic noise; Electrical properties and parameters; Quantum wells; Terahertz detectors; Signal processing; Photodetectors; Electric currents; Antennas; Microoptics; Photoconductive materials
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.5051580

Current noise fluctuations have been investigated in terahertz (THz) quantum well photodetectors embedded in antenna-coupled photonic architectures and compared with standard substrate-coupled mesa detectors. The noise measurements give a value of the photoconductive gain that is in excellent agreement with that extracted from previous responsivity calibrations. Moreover, our results confirm that the noise equivalent power (NEP) of the antenna-coupled devices is of the order of 0.2 pW/Hz0.5. This low NEP value and the wide band frequency response (∼GHz) of the detectors are ideal figures for the development of heterodyne receivers that are, at present, a valuable technological solution to overcome the current limitation of THz sensors.