A. L. Chekhov

Wide tunability of magnetoplasmonic crystals due to excitation of multiple waveguide and plasmon modes

Magnetoplasmonic crystals (MPC) composed of a 1D gold grating on top of a magnetic garnet layer made by a combined ion-beam etching technique are studied. We demonstrate that this method allows to make high-quality MPC. It is shown that MPC with a 30-40 nm thick perforated gold layer provides an effective excitation of two surface plasmon-polariton modes and several numbers of waveguide modes in the garnet layer. An enhancement of the transversal magneto-optical effect up to the value of 10(-2) is observed for all types of resonant modes, that propagate in the magnetic layer, due to magnetic-field control over the mode excitation which is promising for future photonic devices.

High-quality Au/BIG/GGG magnetoplasmonic crystals fabricated by a combined ion-beam etching technique

In this paper we discuss a promising method for the fabrication of magnetoplasmonic crystals (MPC) based on the combined ion-beam etching technique. We show that this method allows producing high-quality planar 1D MPC structures consisting of a gold grating formed on top of a garnet-based magnetic dielectric layer. We demonstrate that resonant features of the MPC, which are determined by surface plasmon-polariton (SPP) and waveguide (WG) mode excitations, can be controlled by a proper choice of the MPC period and the stripe width. Transmission spectra of the MPCs were measured in a wide angular and wavelength range, revealing the excitation of SPP and WG modes of the orders up to m = ±3. The anomalous transmission is observed at normal incidence in the spectral region where Au/garnet SPPs are excited. High values of the linear magneto-optical intensity effect are observed in transmission through the MPC. The effect is odd with respect to the direction of the SPP propagation at the Au/garnet interface and vanishes at the edges of the Brillouin zones, where counter propagating plasmons degenerate into standing waves.

Surface Plasmon-Mediated Nanoscale Localization of Laser-Driven sub-Terahertz Spin Dynamics in Magnetic Dielectrics

We report spatial localization of the effective magnetic field generated via the inverse Faraday effect employing surface plasmon polaritons (SPPs) at Au/garnet interface. Analyzing both numerically and analytically the electric field of the SPPs at this interface, we corroborate our study with a proof-of-concept experiment showing efficient SPP-driven excitation of coherent spin precession with 0.41 THz frequency. We argue that the subdiffractional confinement of the SPP electric field enables strong spatial localization of the SPP-mediated excitation of spin dynamics. We demonstrate two orders of magnitude enhancement of the excitation efficiency at the surface plasmon resonance within a 100 nm layer of a dielectric garnet. Our findings broaden the horizons of ultrafast spin-plasmonics and open pathways toward nonthermal opto-magnetic recording on the nanoscale.

Surface-plasmon enabled control over magnetization dynamics in hybrid magnetoplasmonic crystals

Non-thermal, optical magnetization control and switching offers new opportunities for data recording. Future applications require not only temporal, but also spatial control of magnetization at the nanoscale, which can be realized using surface plasmon polaritons (SPP) — electromagnetic modes highly localized at metal/dielectric interfaces. Here, promising materials are hybrid structures with ferromagnetic iron garnets [1-3], where the laser-induced magnetization switching can be realized using the photomagnetism or the inverse Faraday effect. Recent investigations have shown that plasmonic and magnetic effects can be effectively combined in hybrid magnetoplasmonic crystals consisting of a garnet with a noble metal grating on top (Fig. 1, a) [4, 5]. These structures support SPPs at both sides of the metal grating [6], providing flexibility in the localization of the excitation at the nanoscale and enabling local SPP-assisted manipulation of magnetization. Combining spatial nanoscale with sub-picosecond time resolution, magneto-plasmonics is a promising playground for novel future devices utilizing SPPs for transmitting and recording the magnetically stored data.

Magnetoplasmonic crystals: Resonant linear and nonlinear magnetooptical effects

Results of spectroscopic analysis of the optical second-harmonic (SH) generation in magnetic plasmonic structures comprised of iron garnet and periodic arrays of gold stripes are presented. It is shown experimentally that, in the region of the resonant excitation of a surface plasmon on the metal–magnetic dielectric interface, an increase in the SH intensity and an alternating modulation of the magnetic contrast for the SH, reaching 40%, are observed. The results are described in terms of a nonlinear Fano resonance.

Simulating single-photon-single-atom absorption experiments with an optical resonator

The absorption of a single photon by a single two-level system (TLS) in free space is a fundamental physical process. In this contribution, we present the experimental realization of a model system to simulate the dynamics of such an absorption experiment: Comparing the absorption process of a single photon by a single TLS and the incoupling dynamics of an optical resonator, one finds an analogy between the energy stored inside the resonator and the probability of the photon to be absorbed by the TLS [1]. Both systems, resonators and TLS, respond in an equivalent way to the temporal profile of the incident light pulse. The energy storage in a resonator as well as the absorption of a single photon by a TLS can reach an unit efficiency under idealized conditions. Such an optimized process is achieved by an exponentially rising incident light field with a time constant which matches the lifetime of the system [2]. For such a perfect coupling, the end mirror of the resonator needs to have a reflectivity of unity. This corresponds to the excitation of a TLS from the complete solid angle. For a smaller reflectivity of the end mirror, the cavity simulates the absorption dynamics in the case of excitation from only a part of the solid angle. However, using real mirrors, a good analogy with excitation from a large solid angle can still be obtained by using a strongly asymmetric resonator, i.e. an incoupling mirror which has a significantly lower reflectivity than the end mirror of the cavity.

Porous silicon with metal nanoparticles for silicon solar cells

Composite solar cells formed by a crystalline Si with a thin mesoporous silicon layer infiltrated by plasmonic nanoparticles are studied. Measurements show an increase of quantum efficiency as a result of local field enhancement near nanoparticles due to plasmon resonance.