Plasmonic technology has attracted intense research interest enhancing the functional portfolio o... more Plasmonic technology has attracted intense research interest enhancing the functional portfolio of photonic integrated circuits (PICs) by providing Surface-Plasmon-Polariton (SPP) modes with ultra-high confinement at sub-wavelength scale dimensions and as such increased light matter interaction. However, in most cases plasmonic waveguides rely mainly on noble metals and exhibit high optical losses, impeding their employment in CMOS processes and their practical deployment in highly useful PICs. Hence, merging CMOS compatible plasmonic waveguides with low-loss photonics by judiciously interfacing these two waveguide platforms appears as the most promising route towards the rapid and costefficient manufacturing of high-performance plasmo-photonic integrated circuits. In this work, we present butt-coupled plasmo-photonic interfaces between CMOS compatible 7μm-wide Aluminum (Al) and Copper (Cu) metal stripes and 360×800nm Si3N4 waveguides. The interfaces have been designed by means of 3...
We demonstrate a water cladded plasmo-photonic waveguide, by exploiting the directional coupling ... more We demonstrate a water cladded plasmo-photonic waveguide, by exploiting the directional coupling scheme to vertically divert light from a 360 × 800 nm (height × width) Si 3 N 4 waveguide to a plasmonic slot waveguide, enabling the excitation of a pure plasmonic mode within a 210-nm-wide slot at 1550 nm. The 150-nm-thick plasmonic slot waveguide was deposited on the top of an oxide cladded Si 3 N 4 waveguide exhibiting an experimental plasmonic-to-photonic insertion loss of 2.24 ± 0.3 dB and a plasmonic propagation length (L spp) of 10.8 μm at 1550 nm. The proposed plasmo-photonic waveguide holds a promise as an optical transducer element for highly sensitive and low-cost interferometric biosensors due to the significant phase change achieved per unit propagation length.
We present the design, fabrication and characterization of long-range surface plasmon polariton w... more We present the design, fabrication and characterization of long-range surface plasmon polariton waveguide arrays with materials, mainly silicones, carefully selected with the aim to be used as mechanically flexible single-mode optical interconnections, the socalled "plasmonic arc" working at 1.55µm. The fabricated plasmonic arcs show a TM/TE polarization ratio of ~25 dB. By using the cutback method, the straight propagation loss at 1.55µm is estimated to 0.5-1 dB/mm and coupling loss to ~1-2 dB/facet after dicing. In the free-standing S-curved configuration, the bending loss of single cladding plasmonic arc is 2.2-2.8 dB/90° at bending radius 2.5 mm. For double cladding plasmonic arcs, it is decreased to 0.7-1.7 dB/90° for the same radius. The coupling loss with single-mode glass PCB waveguides is estimated to be 1.7 dB/interface in the best condition. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
The Purcell factor Fp is a key quantity in cavity quantum electrodynamics (cQED) that quantifies ... more The Purcell factor Fp is a key quantity in cavity quantum electrodynamics (cQED) that quantifies the coupling rate between a dipolar emitter and a cavity mode. Its simple form Fp ∝ Q/V unravels the possible strategies to enhance and control light-matter interaction. Practically, efficient light-matter interaction is achieved thanks to either i) high quality factor Q at the basis of cQED or ii) low modal volume V at the basis of nanophotonics and plasmonics. In the last decade, strong efforts have been done to derive a plasmonic Purcell factor in order to transpose cQED concepts to the nanocale, in a scale-law approach. In this work, we discuss the plasmonic Purcell factor for both delocalized (SPP) and localized (LSP) surface-plasmon-polaritons and briefly summarize the expected applications for nanophotonics. On the basis of the SPP resonance shape (Lorentzian or Fano profile), we derive closed form expression for the coupling rate to delocalized plasmons. The quality factor factor and modal confinement of both SPP and LSP are quantified, demonstrating their strongly subwavelength behaviour.
This paper demonstrates the efficiency of the differential method, a conventional grating theory,... more This paper demonstrates the efficiency of the differential method, a conventional grating theory, to investigate dielectric loaded surface plasmon polariton waveguides (DLSPPWs), known to be a potential solution for optical interconnects. The method is used to obtain the mode effective indices (both real and imaginary parts) and the mode profiles. The results obtained with the differential method are found to be in good agreement with those provided by the effective index method or finite elements. The versatility of the differential method is demonstrated by considering complex configurations such as trapezoidal waveguides or DLSPPWs lying on a finite width metal stripe.
Nevertheless, data communication and power consumption are still daunting issues in Data Centers ... more Nevertheless, data communication and power consumption are still daunting issues in Data Centers and HPCs. According to recent predictions made in [4], the barrier of 10PFlops Plasmonics-Principles and Applications 524 computing performance should have been overcome in 2012 by a supercomputer that consumes 5MW of power [5]. In addition, [4] predicted that exascale supercomputing machines would consume 20MW having a power efficiency of 1mW/Gb/s [5]. Nonetheless, power consumption in such environments has been proven to be even higher than expected: Today's top-ranked supercomputer, the "K computer", has already reached the 10PFlops performance benchmark but at the expense of excessive consumed power that is more than twice [6] the value that was predicted in 2008. All the above imply that the use of optics at inter-rack communication level is not enough for delivering the necessary performance enhancements. Therefore, the optical technology should now be exploited at shrinked networking environments: The penetration of low-energy photonic solutions at board-toboard, chip-to-chip and eventually intra-chip interconnects would yield remarkable savings in energy consumption [7]. The current mainstream photonic route with high integration and low-cost perspectives relies on the Silicon-on-Insulator (SOI) photonics platform, whose growing maturity is soon expected to release Tb/s-scale data transmission and switching capabilities in datacom and computercom units ensuring low latency, low power consumption and chip-scale integration credentials [8].
The development of near-field optics theory is reviewed. We first recall that near-field optics i... more The development of near-field optics theory is reviewed. We first recall that near-field optics is not limited to near-field microscopy. Broadly speaking, it concerns phenomena involving evanescent electromagnetic waves. The importance of such waves was ignored for a long time in optical and surface physics until the emergence of scanning near-field optical microscopes. Taking evanescent waves into account prevents the use of any simple approximation in the set of Maxwell's equations. The various theoretical approaches of near-field optics are discussed from the point of view of their ability to assess evanescent electromagnetic waves. We discuss the main results of the application of the various practical schemes which all rely on a numerical procedure.
We consider wavelength-selective splitting of radiation using directional couplers (DCs) formed b... more We consider wavelength-selective splitting of radiation using directional couplers (DCs) formed by dielectricloaded surface-plasmon-polariton waveguides (DLSPPWs). The DCs were fabricated by depositing subwavelength-sized polymer ridges on a gold film using large-scale UV photolithography and characterized at telecommunications wavelengths with near-field microscopy. We demonstrate a DLSPPW-based 45-m-long DC comprising 3 m offset S bends and 25-m-long parallel waveguides that changes from the "through" state at 1500 nm to 3 dB splitting at 1600 nm, and show that a 50.5-m-long DC should enable complete separation of the radiation channels at 1400 and 1620 nm. The DC performance is found to be in good agreement with full vectorial three-dimensional finite-element simulations.
The experimental observation of a one-dimensional evanescent wave supported by a 90 • metal edge ... more The experimental observation of a one-dimensional evanescent wave supported by a 90 • metal edge is reported. Through a measurement of in-plane momenta, we clearly demonstrate the dimensional character of this surface wave and show that it is non-radiative in the superstrate. Excitation conditions, lateral extension and polarization properties of this wave are discussed. Finally, we explore the effect of the surrounding dielectric medium and demonstrate that a single edge can sustain distinct excitations.
We analytically and numerically analyze the fluorescence decay rate of a quantum emitter placed i... more We analytically and numerically analyze the fluorescence decay rate of a quantum emitter placed in the vicinity of a spherical metallic particle of mesoscopic size (i.e with dimensions comparable to the emission wavelength). We discuss the efficiency of the radiative decay rate and non-radiative coupling to the particle as well as their distance dependence. The electromagnetic coupling mechanisms between the emitter and the particle are investigated by analyzing the role of the plasmon modes and their nature (dipole, multipole or interface mode). We demonstrate that near-field coupling can be expressed in a simple form verifying the optical theorem for each particle modes.
We report on monitoring the mode power in dielectric-loaded surface plasmon polariton waveguides ... more We report on monitoring the mode power in dielectric-loaded surface plasmon polariton waveguides (DLSPPWs) by measuring the resistance of gold electrodes, supporting the DLSPPW mode propagation, with internal (on-chip) Wheatstone bridges. The investigated DLSPPW configuration consisted of 1-μm-thick and 10-μm-wide cycloaliphatic acrylate polymer ridges tapered laterally to a 1-μm-wide ridge placed on a 50-nm-thin and 4-um wide gold stripe, all supported by a ~1.7-µm-thick Cytop layer deposited on a Si wafer. The fabricated DLSPPW power monitors were characterized at telecom wavelengths, showing very high responsivities reaching up to ~6.4 μV/μW (for a bias voltage of 245 mV) and the operation bandwidth exceeding 40 kHz.
The design, fabrication, characterization, and modeling of basic building blocks of plasmonic cir... more The design, fabrication, characterization, and modeling of basic building blocks of plasmonic circuitry based on dielectric-loaded surface polariton waveguides, such as bends, splitters, and Mach-Zehnder interferometers are presented. The plasmonic components are realized by depositing subwavelength dielectric ridges on a smooth gold film using mass-production-compatible UV-photolithography. The near-field characterization at telecommunication wavelengths shows the strong mode confinement and low radiation and bend losses. The performance of the devices is found in good agreement with results obtained by full vectorial three-dimensional finite element simulations.
We use superresolution single-molecule polarization and lifetime imaging to probe the local densi... more We use superresolution single-molecule polarization and lifetime imaging to probe the local density of states (LDOS) in a metal nanocavity. Determination of the orientation of the molecular transition dipole allows us to retrieve the different LDOS behavior for parallel and perpendicular orientations with respect to the metal interfaces. For the perpendicular orientation, a strong lifetime reduction is observed for distances up to 150 nm from the cavity edge due to coupling to surface plasmon polariton modes in the metal. Contrarily, for the parallel orientation we observe lifetime variations resulting from coupling to characteristic λ/2 cavity modes. Our results are in good agreement with calculations of the nanoscale variations of the projected LDOS, which demonstrates the potential of single molecules as nonperturbative, nanoscale vectorial point probes in photonic and biological nanostructures.
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Papers by Alain Dereux