High-sensitivity plasmo-photonic interferometric sensors on a chip

Abstract

Optical refractive index (RI) sensors exploiting selective co-integration of plasmonics with silicon photonics in Lab-on-achip configurations are expected to disrupt Point-of-Care (POC) diagnostics, delivering performance and economic breakthroughs. Propagating surface-plasmon-polariton modes offer superior sensitivity due to their extreme overlap with the surrounding medium. In parallel, low-loss photonics act as the hosting platform with which the plasmonic losses can be sustained while allowing for multiplexed layouts via in-plane SPP excitation schemes. However, merging plasmonics with silicon photonics in a cost-effective manner, requires a truly CMOS-compatible manufacturing process. Herein, we demonstrate experimentally, the highest bulk-sensitivity among all the plasmo-photonic interferometric RI sensors, while taking the leap forward in the development of a CMOS-manufactured plasmo-photonic sensing platform merging Si3N4 photonics and aluminum plasmonics. The proposed structure relies on a butt-coupled interface between Si3N4 waveguides and a 70 μm long plasmonic stripe, deployed in one branch of a Mach-Zehnder Interferometer (MZI) serving as the sensing transducer that detects local changes in the refractive index. The lower MZI arm (reference arm) exploits the low-loss Si3N4 platform to deploy a MZI-based variable optical attenuator followed by a thermo-optic phase shifter to optimize the sensor performance achieving resonance extinction ratio values at the MZI output of more than 35 dB. Experimental evaluation of a gold-based sensor revealed a bulk refractive index sensitivity of 1930 nm/RIU. In addition, we experimentally demonstrate that the proposed plasmo-photonic waveguide platform can migrate from gold (Au) to Aluminum (Al), demonstrating the first step towards a fully CMOS compatible plasmo-photonic interferometric sensor.

Authors 16

1. E. Chatzianagnostou

   Aristotle University of Thessaloniki

   Affiliation as printed

   Aristotle Univ. of Thessaloniki (Greece)

2. Athanasios Manolis

   Aristotle University of Thessaloniki

   Affiliation as printed

   Aristotle Univ. of Thessaloniki (Greece)

3. George Dabos

   Aristotle University of Thessaloniki

   Affiliation as printed

   Aristotle Univ. of Thessaloniki (Greece)

4. Dimitra A. Ketzaki

   Aristotle University of Thessaloniki

   Affiliation as printed

   Aristotle Univ. of Thessaloniki (Greece)

5. Bartos Chmielak Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Advanced Microelectronic Ctr. Aachen (Germany)

6. Anna Lena Giesecke Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Advanced Microelectronic Ctr. Aachen (Germany)

7. Caroline Porschatis Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Advanced Microelectronic Ctr. Aachen (Germany)

8. Piotr Jacek Cegielski Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Advanced Microelectronic Ctr. Aachen (Germany)

9. Stephan Suckow Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Advanced Microelectronic Ctr. Aachen (Germany)

10. Laurent Markey

    Centre National de la Recherche Scientifique · Université de Bourgogne

    Affiliation as printed

    CNRS, Univ. de Bourgogne (France)

11. Jean‐Claude Weeber

    Centre National de la Recherche Scientifique · Université de Bourgogne

    Affiliation as printed

    CNRS, Univ. de Bourgogne (France)

12. Alain Dereux

    Centre National de la Recherche Scientifique · Université de Bourgogne

    Affiliation as printed

    CNRS, Univ. de Bourgogne (France)

13. Stefan Schrittwieser

    AIT Austrian Institute of Technology GmbH

    Affiliation as printed

    AIT Austrian Institute of Technology (Austria)

14. Rudolf Heer

    AIT Austrian Institute of Technology GmbH

    Affiliation as printed

    AIT Austrian Institute of Technology (Austria)

15. Nikos Pleros

    Aristotle University of Thessaloniki

    Affiliation as printed

    Aristotle Univ. of Thessaloniki (Greece)

16. D. Tsiokos

    Aristotle University of Thessaloniki

    Affiliation as printed

    Aristotle Univ. of Thessaloniki (Greece)

    Bialoom Ltd. (Cyprus)