Erlangen 2022 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 5: Quantum Technologies I

Q 5.8: Talk

Monday, March 14, 2022, 15:45–16:00, Q-H13

Near-infrared single photon detector with µHz dark count rate — Katharina-Sophie Isleif and •ALPS Collaboration — Deutsches-Elektronen Synchrotron DESY, Hamburg, Germany

On behalf of the ALPS Collaboration we present the use of near-infrared photon-counting technology with µHz dark count rate in the Any Light Particle Search (ALPS II) at DESY. ALPS II is a laboratory-based light shining through a wall experiment that searches for axion-like particles (ALPs). It will utilize a superconducting transition edge sensor (TES) to detect single photons at a wavelength of 1064 nm, which are converted from axion-like particles about once per day assuming an axion-photon coupling strength of g_aγγ ≈ 2 × 10⁻¹¹ GeV⁻¹. To detect this weak signal, a low dark count rate, a high detection efficiency and a good energy resolution are required. We present the experimental setup of the TES and how we reach an intrinsic dark count rate of µHz by using analysis routines in the time and frequency domain. Connecting an optical fiber increases the rate by three orders of magnitude, which can be explained by blackbody radiation and can be decreased by improving the detector’s energy resolution and other measures. Additionally, we present the setup for characterizing system detection efficiency using a calibrated single photon source.