Cryogenic thermoelectric (QVD) detectors: Emerging technique for fast single-photon counting and non-dispersive energy characterization

• Published in: Journal of modern optics 2004-06, Vol.51 (9-10), p.1467-1490
• Main Authors: Gulian, A., Wood, K., Vechten, D. van, Fritz, G.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Optics; Physics; Quantum optics
• ISSN: 0950-0340; 1362-3044
• DOI: 10.1080/09500340408235286

"QVD"detectors are based on thermoelectric heat-to-voltage (Q V) conversion and digital (V D) readout. We have devised and analyzed the performance of QVD detectors with several different sensor designs that enable use of high thermoelectric figure of merit samples, be they of thin film, bulk crystal, or whisker form. Our first QVD devices had the well-studied material Au-Fe as thin film sensors. More recently, we have confirmed the literature reports of substantially higher Seebeck coefficient at cryogenic temperatures in lanthanum (cerium) hexaborides. We have also investigated the kinetic properties of La(Ce)B 6 crystals with different La - Ce ratios. Currently we are exploring prototype devices based on bulk single-crystalline sensors. These include a successfully tested candidate with a sharpend hexaboride sensor and small-size bismuth absorber - a whisker prototype. In theory, QVD sensors are competitive with superconducting tunnel junction (STJ) and transition edge sensor (TES) devices in energy resolution ability. However, QVD sensors ought to be able to respond at very much faster rates than these competitors; the lanthanum-cerium hexaboride sensors are expected to reach rates of 100 MHz counting rates for UV/optical photons. In addition to traditional astrophysical applications, these detectors can be applied to the tasks of quantum computing and communication.