Regensburg 2019 – scientific programme
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O: Fachverband Oberflächenphysik
O 72: Poster Wednesday: Scanning Probe Techniques
O 72.9: Poster
Wednesday, April 3, 2019, 17:45–20:00, Poster B2
Collection and Detection Mechanisms for Photons Emerging from Tunnel Junctions — •Berk Zengin1,2, Hugo Cabrera2, Dilek Yildiz2,3, Danilo Pescia2, and Oguzhan Gürlü1,2 — 1Istanbul Technical University, Department of Physics, 34460, Istanbul, Turkey — 2ETH Zurich, 8093, Zurich, Switzerland — 3University of Basel, Basel, Switzerland
Even though photon emission from planar tunneling junctions were studied long before the invention of Scanning Tunneling Microscope (STM), studies on such photon generation mechanisms are gaining more interest in recent years. Several photon collection and detection mechanisms with high efficiencies were reported. We constructed several photon collection mechanisms on a commercial STM system. In one, emitted photons were collected using a fiber that was placed in proximity of tunneling junction, mounted on a manual positioner. Based on simulations carried out by finite element methods, a ball lens was placed in between fiber and the junction to increase coupling efficiency and results were compared accordingly. Furthermore, a bundle of two fiber cores were used to detect photons in order to perform two channel photon detection from the tunnel junction. Two types of detectors were utilized for photon collection process. Our results indicate that photon maps acquired simultaneously with topography and tunneling current maps can show contrast between neighboring data points, demonstrating a resolution with several Angstroms. In general, we address the challenges of interpretation of photon maps obtained under ambient conditions due to changes at the tip apex.