Berlin 2014 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 54: Photonics I

Q 54.1: Group Report

Friday, March 21, 2014, 10:30–11:00, UDL HS3038

Nondestructive Detection of an Optical Photon — •Andreas Reiserer, Stephan Ritter, and Gerhard Rempe — Hans-Kopfermann-Str. 1, 85748 Garching, Germany

We demonstrate a robust photon detector which does not rely on absorption. Instead, impinging light is reflected off an optical resonator containing a single atom in a superposition of two states. Upon reflection of a single photon, the phase of the superposition state is flipped, which allows us to nondestructively detect the photon.

This experimental achievement has two major consequences: First, it facilitates repeated measurements of one and the same photon, which boosts the photon detection efficiency. Second, nondestructive detection can serve as a herald that signals the presence of a photon without affecting its unmeasured degrees of freedom, like its temporal shape or its polarization. This is in stark contrast to absorbing detectors, where the photon and its quantum state are irreversibly lost. Both implications are of great importance for the rapidly evolving research fields of quantum measurement, quantum computation, quantum communication, and quantum networks.