Surface plasmon resonance enhanced transverse magneto-optical Kerr effect and the detection performance of nanopore arrays

The introduction of a magnetic component to the surface plasmon resonance (SPR) structure to form a magneto-optical surface plasmonic resonance (MOSPR) detector is an effective method for enhancing the detection limit for small molecules at low concentrations. This is important for biosensing, early disease diagnosis, drug discovery, and the detection of contamination in solutions and gases. In this study, a MOSPR crystal composed of a Co6Ag94 slab covered by a subwavelength periodic square array of gold (Au) nanopores was designed to theoretically examine the mechanism by which MOSPR crystals detect glucose concentrations through the transverse magneto-optical Kerr effect (T-MOKE). Owing to the excitation of SPR at the interface between the glucose solution and Au film, a Fano-like sharp T-MOKE spectrum with a narrow linewidth and a high amplitude was obtained, thus producing a high sensitivity of 159° RIU−1 and a high figure of merit (FOM) of the order of 103 RIU−1. This corresponds to a glucose detection limit of 0.0066 g/ml, which is more accurate than that previously reported. This design provides an alternative method for detecting analytes’ concentrations in aqueous environments.

Solving Generalized Nonlinear Schrödinger Equation by Adomian Decomposition Technique

In this paper, using a suitable change of variable and applying the Adomian decomposition method to the generalized nonlinear Schr¨odinger equation, we obtain the analytical solution, taking into account the parameters such as the self-steepening factor, the second-order dispersive parameter, the third-order dispersive parameter and the nonlinear Kerr effect coefficient, for pulses that contain just a few optical cycle. The analytical solutions are plotted. Under influence of these effects, pulse did not maintain its initial shape.

Observation of spatial nonlinear self-cleaning in a few-mode step-index fiber for special distributions of initial excited modes

In this paper, we experimentally demonstrate that a nonlinear Kerr effect in suitable coupling conditions can introduce a spatially self-cleaned output beam for a few-mode step-index fiber. The impact of the distribution of the initial excited modes on spatial beam self-cleaning has been demonstrated. It is also shown experimentally that for specific initial conditions, the output spatial pattern of the pulsed laser can be reshaped into the LP11 mode due to nonlinear coupling among the propagating modes. Self-cleaning into LP11 mode required higher input powers with respect to the power threshold for LP01 mode self-cleaning. Our experimental results are in agreement with the results of numerical calculations.

Direct measurement of magnon temperature by magneto-optic Kerr effect in YIG

Magnon-phonon thermal relaxation holds a fundamental role in condensed matter physics, and the difference between local phonon and magnon temperature ΔTmp as an important part of this subfield was theoretically considered responsible for the spin Seebeck effect. Experimental determination of ΔTmp is necessary to give more insight into magnon-phonon coupling. Here we report spatially resolved measurements of magnon temperature performed by magneto-optic Kerr effect in yttrium iron garnet. Our results indicate a strong interaction between magnon and phonon subsystems in YIG with an upper limit of the phonon-magnon thermal relaxation length of 1.4 mm, and means this method is valid.

A tutorial on fiber Kerr nonlinearity effect and its compensation in optical communication systems

The advent of silica-based low-cost standard single-mode fibers revolutionized the whole communication industry. The deployment of optical fibers in the networks induces a paradigm shift in the communication technologies used for long-haul information transfer. However, the communication using the optical fibers is affected by several linear and nonlinear effects. The most common linear effects are attenuation and chromatic dispersion, whereas the dominant nonlinear effect is the Kerr effect. The Kerr effect induces a power-dependent nonlinear distortion for the signal propagating in the optical fiber. The detrimental effects of the Kerr nonlinearity limit the capacity of long-haul optical communication systems. Fiber Kerr nonlinearity compensation using digital signal processing (DSP) techniques has been well investigated over several years. In this paper, we provide a comprehensive tutorial, including the fundamental mathematical analysis, on the characteristics of the optical fiber channel, the origin of the Kerr nonlinearity effect, the theory of the pulse propagation in the optical fiber, and the numerical and analytical tools for solving the pulse propagation equation. In addition, we provide a concise review of various DSP techniques for fiber nonlinearity compensation, such as digital back-propagation, Volterra series-based nonlinearity equalization, perturbation theory-based nonlinearity compensation, and phase conjugation. We also carry out numerical simulation and the complexity evaluation of the selected nonlinearity compensation techniques.

Theoretical Study on Metasurfaces for Transverse Magneto-Optical Kerr Effect Enhancement of Ultra-Thin Magnetic Dielectric Films

We study how to enhance the transverse magneto-optical Kerr effect (TMOKE) of ultra-thin magnetic dielectric films through the excitation of strong magnetic resonances on metasurface with a metal nanowire array stacked above a metal substrate with an ultra-thin magnetic dielectric film spacer. The plasmonic hybridizations between the Au nanowires and substrate result in magnetic resonances. The periodic arrangement of the Au nanowires can excite propagating surface plasmon polaritons (SPPs) on the metal surface. When the SPPs and the magnetic resonances hybridize, they can strongly couple to form two strong magnetic resonances, which are explained by a coupled oscillator model. Importantly, benefitting from the strong magnetic resonances, we can achieve a large TMOKE signal up to 26% in the ultra-thin magnetic dielectric film with a thickness of only 30 nm, which may find potential applications in nanophotonics, magnonics, and spintronics.