Presentation
17 September 2018 Manipulation and measurement of optical coherence in PT photonic structures (Conference Presentation)
Author Affiliations +
Abstract
Optical coherence is of fundamental importance for both classical and quantum applications. This motivates the development of approaches for increasing the degree of coherence, which can be quantified by a measure of purity. The purity is preserved in linear conservative systems, and accordingly the manipulation of coherence was realized with specially introduced loss in bulk optical setups or diffraction on metal films involving optical absorption and plasmon coupling. Here we suggest and show experimentally for the first time that manipulation and measurement of optical coherence and state purification can be efficiently realized in integrated non-Hermitian parity-time (PT) symmetric photonic structures composed of elements with different loss or gain. Specifically, we design and fabricate laser-written waveguide directional couplers that contain two sections. The first section realizes a PT-like coupler, where one of the two waveguides features extra radiative losses via modulation. The second section consists of straight coupled waveguides with specially detuned propagation constants, which are optimized to enable a full reconstruction of the purity and optical coherence by measuring the interference pattern in both waveguides through fluorescence imaging. In PT symmetric regime, we observe that the purity of an initially fully incoherent (mixed) state is increased followed by a revival of the input state. This constitutes an important experimental evidence of reversible manipulation of light coherence in PT coupled waveguides. We anticipate that this method can facilitate a wide range of applications from classical to quantum optics, including filtering out noise and optimizing the visibility of interferometric measurements.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kai Wang, Sergey V. Suchkov, James G. Titchener, Steffen Weimann, Demetrios N. Christodoulides, Alexander Szameit, and Andrey A. Sukhorukov "Manipulation and measurement of optical coherence in PT photonic structures (Conference Presentation)", Proc. SPIE 10721, Active Photonic Platforms X, 107211P (17 September 2018); https://doi.org/10.1117/12.2320395
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KEYWORDS
Coherence (optics)

Optical testing

Waveguides

Absorption

Diffraction

Integrated optics

Laser development

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