Advances in Superconducting Single-photon Detectors

Superconducting single-photon detectors can detect photons from the UV to the infrared with quantum efficiencies above 90% and greater than MHz count rates. They consist of narrow, thin wires of superconductor biased near their critical current. When these wires absorb a photon, part of the wire stops superconducting and becomes resistive. This transition and sudden jump in resistance is what enables the detection of the photon. Over the past two decades, these devices have matured greatly as a technology and have found many applications ranging from quantum optics to astronomy. However, there are still multiple theories of the dominant mechanism behind these devices. Recently proposed theories suggest a more complicated but potentially more powerful detection mechanism, and experiments are only recently starting to demonstrate this effect and its potential applications. In this research, the capability to fabricate these intricate devices was developed. This requires high-quality deposition of the superconductors, precise machining of the devices with electron beam lithography, and accurate etching of the films. Many parts of the process have been characterized. Additionally, two new directions are being explored. The first attempts to exploit the recently proposed detection mechanism to make detectors with much wider wires, leading to faster detection rates. The second is the fabrication of superconducting single-photon detectors directly onto optical fibers, eliminating the need for complicated coupling structures and alignment of the detector with the fiber.The Ohio State University College of Engineering Undergraduate Research ScholarshipNo embargoAcademic Major: Engineering Physic