Energy Collection Efficiency of Tungsten Transition-Edge Sensors in the Near-Infrared

Single-photon detectors operating at visible and near-infrared wavelengths with high detection efficiency and low noise are a requirement for many quantum-information applications. Detection of visible and near-infrared light at the single-photon level and discrimination between one- and two-photon absorption events place stringent requirements on TES design in terms of heat capacity, thermometry, and optical detection efficiency. Energy loss in the conversion of the photon energy in tungsten TESs to heat degrades the performance of these devices. By fabricating TESs on surface-micromachined Si₃N₄ membranes we improved the energy collection efficiency by a factor of two, to ∼80% energy efficiency.