We report the realization of a two--dimensional optical microscope for surface plasmons polaritons (SPPs) based on parabolic Bragg mirrors. These mirrors are built from lithographically fabricated gold nanostructures on gold thin films. We show by direct imaging by leakage radiation microscopy that the magnification power of the SPP microscope follows basic predictions of geometrical optics. Spatial resolution down to the value set by the diffraction limit is demonstrated.
A new platform for fabricating polariton lasers operating at room temperature is introduced: nitride-based distributed Bragg reflectors epitaxially grown on patterned silicon substrates. The patterning allows for an enhanced strain relaxation thereby enabling to stack a large number of crack-free AlN/AlGaN pairs and achieve cavity quality factors of several thousands with a large spatial homogeneity. GaN and ZnO active regions are epitaxially grown thereon and the cavities are completed with top dielectric Bragg reflectors. The two structures display strong-coupling and polariton lasing at roo…
Photocurrent is arising as a powerful tool for detecting in-plane collective excitations in hybrid polariton systems. In this paper, based on the intrinsic optoelectric response of graphene, photocurrent imaging of in-plane plasmons from each graphene layer is presented in a hybrid graphene-graphene heterostructure. In combination with near-field optical signals which detect plasmons above the sample, three dimensional detection of hybrid plasmons is demonstrated. Especially, only an electronic boundary is necessary for the electrical detection of hybrid plasmons, which acts as both the photoc…
We present a quantitative experimental analysis of a surface plasmon polariton (SPP) interferometer relying on elliptical Bragg mirrors. By using a leakage radiation microscope we observe oscillation fringes with unit visibility at the two interferometer exits. We study the properties of the SPP beam splitter and determine experimentally both the norm and phase of the SPP reflection and transmission coefficients.
We report the realization of a dual surface plasmon polariton (SPP) microscope based on leakage radiation (LR) analysis. The microscope can either image SPP propagation in the direct space or tin the Fourier space. This particularity allows in turn manipulation of the LR image for a clear separation of different interfering SPP contributions present close to optical nanoelements.
Tamm plasmon provides a new avenue in plasmonics of interface states in planar multilayer structures due to its strong light matter interaction. This article reviews the research and development in Tamm plasmon polariton excited at the interface of a metal and a distributed Bragg reflector. Tamm plasmon offers an easy planar solution compared to patterned surface plasmon devices with huge field enhancement at the interface and does not require of any phase matching method for its excitation. The ease of depositing multilayer thin film stacks, direct optical excitation, and high-Q modes make Ta…
We theoretically study resonance responses of flat surfaces and sharp edges of the nanostructures that support excitations of phonon-polaritons in mid-infrared range. We focus on two materials: silicon carbide that has a nearly isotropic permittivity and hexagonal boron nitride that has a strong anisotropy and spectral band with hyperbolic dispersion. We aim to predict scattering-type near-field optical microscope (s-SNOM) response and develop a modeling approach that adequately describes the resonant behavior of the nanostructure with phonon-polaritons. The previously employed technique assum…
We report the experimental realization of an elliptical Bragg reflector acting as an interferometer for propagating surface plasmon sSPd waves. We investigate SP interferometry in this device using a leakage radiation microscope and we compare our observations with a theoretical model for SP propagation. Strong SP focalization as a function of laser polarization orientation is observed and justified.
Polaritons are compositional light-matter quasiparticles that have recently enabled remarkable breakthroughs in quantum and nonlinear optics, as well as in material science. Despite the enormous progress, however, a direct nanometer-scale visualization of polaritons has remained an open challenge. Here, we demonstrate that plasmon-exciton polaritons, or plexcitons, generated by a hybrid system composed of an individual silver nanoparticle and a few-layer transition metal dichalcogenide can be spectroscopically mapped with nanometer spatial resolution using electron energy loss spectroscopy in …
We present a method to implement 3-dimensional polariton confinement with in-situ spectral tuning of the cavity mode. Our tunable microcavity is a hybrid system consisting of a bottom semiconductor distributed Bragg reflector (DBR) with a cavity containing quantum wells (QWs) grown on top and a dielectric concave DBR separated by a micrometer sized gap. Nanopositioners allow independent positioning of the two mirrors and the cavity mode energy can be tuned by controlling the distance between them. When close to resonance we observe a characteristic anticrossing between the cavity modes and the…
Near-field optical microscopes with two independent tips for simultaneous excitation and detection can be essential tools for studying localized optical phenomena on the subwavelength scale. Here, we report on the implementation of a fully automated and robust dual-tip scanning near-field optical microscope (SNOM), in which the excitation tip is stationary, while the detection tip automatically scans the surrounding area. To monitor and control the distance between the two probes, mechanical interactions due to shear forces are used. We experimentally investigate suitable scan parameters and f…
In quantum mechanics, entanglement and correlations are not just a mere sporadic curiosity, but rather common phenomena at the basis of an interacting quantum system. In electron microscopy, such concepts have not been extensively explored yet in all their implications; in particular, inelastic scattering can be reanalyzed in terms of correlation between the electron beam and the sample. While classical inelastic scattering simply implies loss of coherence in the electron beam, performing a joint measurement on the electron beam and the sample excitation could restore the coherence and the los…
We present optical investigations of rectangular surface plasmon polariton waveguides lithographically defined on GaAs substrates. The plasmon propagation length is directly determined using a confocal microscope, with independent polarization control in both excitation and detection channels. Surface plasmon polaritons are launched along the waveguide using a lithographically defined defect at one end. At the remote end of the waveguide they scatter into the far-field, where they are imaged using a CCD camera. By monitoring the length dependence of the intensity of scattered light from the wa…
The key challenge in current research into electromagnetic cloaking is to achieve invisibility over an extended bandwidth. There has been significant progress towards this using the idea of cloaking by sweeping under the carpet of Li and Pendry, with dielectric structures superposed on a mirror. Here, we show that we can harness surface plasmon polaritons at a metal surface structured with a dielectric material to obtain a unique control of their propagation. We exploit this to control plasmonic coupling and demonstrate both theoretically and experimentally cloaking over an unprecedented bandw…
We report a nano-infrared (IR) imaging study of trilayer graphene (TLG) with both ABA (Bernal) and ABC (rhombohedral) stacking orders using the scattering-type scanning near-field optical microscope (s-SNOM). With s-SNOM operating in the mid-IR region, we mapped in real space the surface plasmon polaritons (SPPs) of ABA-TLG and ABC-TLG, which are tunable with electrical gating. Through quantitative modeling of the plasmonic imaging data, we found that the plasmon wavelength of ABA-TLG is significantly larger than that of ABC-TLG, resulting in a sizable impedance mismatch and hence a strong pla…
We present an optical investigation of surface plasmon polaritons propagating along nanoscale Au-wires, lithographically defined on GaAs substrates. A two-axis confocal microscope was used to perform spatially and polarization resolved measurements in order to confirm the guiding of surface plasmon polaritons over lengths ranging from $5-20 μm$ along nanowires with a lateral dimension of only $\approx 100 nm$. Finite difference time domain simulations are used to corroborate our experimental observations and highlight the potential to couple proximal quantum dot emitters to propagating plasmon…
In this paper, we theoretically and numerically demonstrate a two-dimensional Metal-Dielectric-Metal (MDM) waveguide based on finite-difference time-domain simulation of the propagation characteristics of surface plasmon polaritons (SPPs). For practical applications, we propose a plasmonic Y-branch waveguide based on MDM structure for high integration. The simulation results show that the Y-branch waveguide proposed here makes optical splitter with large branching angle (~180 degree) come true. We also introduce a finite array of periodic tooth structure on one surface of the MDM waveguide whi…
Leakage-radiation microscopy of a thin gold film demonstrates the ability of an ensemble of fluorescent diamond nanoparticles attached onto the apex of an optical tip to serve as an efficient near-field surface-plasmon polariton launcher. The implementation of the nanodiamond-based tip in a near-field scanning optical microscope will allow for an accurate control on the launching position, thereby opening the way to scanning plasmonics.
We present an overview of recent progress in plasmonics. We focus our study on the observation and excitation of surface plasmon polaritons (SPPs) with optical near-field microscopy. We discuss in particular recent applications of photon scanning tunnelling microscope (PSTM) for imaging of SPP propagating in metal and dielectric wave guides. We show how near-field scanning optical microscopy (NSOM) can be used to optically and actively address remotely nano-objects such as quantum dots. Additionally we compare results obtained with near-field microscopy to those obtained with other optical far…
Plasmonics is an interdisciplinary field focusing on the unique properties of both localized and propagating surface plasmon polaritons (SPPs) - quasiparticles in which photons are coupled to the quasi-free electrons of metals. In particular, it allows for confining light in dimensions smaller than the wavelength of photons in free space, and makes it possible to match the different length scales associated with photonics and electronics in a single nanoscale device. Broad applications of plasmonics have been realized including biological sensing, sub-diffraction-limit imaging, focusing and li…
