Speaker
Description
Cryogenic transition edge sensors (TESs) are single photon detectors featuring high quantum efficiency and excellent energy resolution below 10% at optical and near-infrared wavelengths. If thermal backgrounds can be suppressed to sufficiently low levels, such detectors would be ideally suited for experiments searching for photon-axion conversion at these wavelengths such as light-shining-through-a-wall (LSW) experiments or axion interferometers. Here, we report on the determination of the system detection efficiency of the TES intended for a future run at the LSW experiment Any Light Particle Search II (ALPS II). With our latest experimental setup, we are able to achieve an SDE $\gtrsim$ 80%. Furthermore, we report on a novel cold optical filter bench that could suppress backgrounds by more than two orders of magnitude. The filter bench can be remotely aligned and first results indicate a transmission of $\gtrsim$ 60%.
