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Abstract We designed a simple on-chip integrated optical isolator made up of a metal–insulator–metal waveguide and a disc cavity filled with magneto-optical material to enhance the transverse magneto-optical effect through the coin paradox spin–orbit interaction (SOI). The simulation results of the non-reciprocal transmission properties of this optical structure show that a high-performance on-chip integrated optical isolator is obtained. The maximum isolation ratio is greater than 60 dB with a corresponding insertion loss of about 2 dB. The great performance of the optical isolator is attributed to the strong transverse magneto-optical effect, which is enhanced by the coin paradox SOI. Moreover, the enhancement of the transverse magneto-optical effect through the coin paradox SOI is more substantial for smaller azimuthal mode number n. Benefiting from this, the transverse magneto-optical effect remains strong in a wide wavelength range. Additionally, a smaller cavity has a stronger transverse magneto-optical effect in the same wavelength range. Our research provides a new perspective for creating highly integrated magneto-optical devices.

We designed a simple on-chip integrated optical isolator made up of a metal–insulator–metal waveguide and a disc cavity filled with magneto-optical material to enhance the transverse magneto-optical effect through the coin paradox spin–orbit interaction (SOI). The simulation results of the non-reciprocal transmission properties of this optical structure show that a high-performance on-chip integrated optical isolator is obtained. The maximum isolation ratio is greater than 60 dB with a corresponding insertion loss of about 2 dB. The great performance of the optical isolator is attributed to the strong transverse magneto-optical effect, which is enhanced by the coin paradox SOI. Moreover, the enhancement of the transverse magneto-optical effect through the coin paradox SOI is more substantial for smaller azimuthal mode number n. Benefiting from this, the transverse magneto-optical effect remains strong in a wide wavelength range. Additionally, a smaller cavity has a stronger transverse magneto-optical effect in the same wavelength range. Our research provides a new perspective for creating highly integrated magneto-optical devices. [ABSTRACT FROM AUTHOR]

The whispering gallery modes (WGMs) are studied theoretically in a proposed magneto-optic (MO) silicon micro-ring resonator with a radial magnetic field. The dispersion relations between both the frequency and polarization of the resonant mode and the gyration coefficient are achieved through Finite-Element Method (FEM). Nonreciprocal polarization coupling is observed between the intrinsic quasi-TM and quasi-TE modes, due to their different frequency shift coefficients originating from the magneto-optic effect. This polarization coupling results in the rapid changes of linear polarization degrees of the supermodes. The nonreciprocal mode coupling is universal and will be of practical value for the MO optical integration. [ABSTRACT FROM AUTHOR]

In this work, the narrowband and broadband absorption characteristics of single layer graphene-based photonic structures are investigated. The optical features were determined utilizing the 4 × 4 transfer matrix method. The results indicate that the proposed design incorporating monolayer graphene achieves absorption rates exceeding 90% across a bandwidth of 1.8 THz. Additionally, the suggested photonic configuration has the potential to function as a triple-mode narrowband absorber through the alteration of layer positioning or the substitution of materials. The numerical relationships between the refractive indexes of materials A, B, and C have been formulated to facilitate broadband and narrowband absorption. The absorption characteristics of the proposed design have been significantly influenced by the Fermi-level of Graphene and the magnetic field. The results indicate that the absorption value of both broadband and narrowband absorbers can be dynamically adjusted by manipulating the Fermi-level of Graphene and magnetic field. The photonic configuration being proposed presents novel opportunities for the development of electrically and magnetically tunable narrowband and broadband absorbers. • The proposed design can offer both broadband and multi-mode narrowband absorption. • The triple-mode narrowband absorption with a value greater than 95% achieved. • The proposed novel design provided broadband absorption over a bandwidth of 1.8 THz. • Formulated numerical relations for broadband and multi-mode absorption. • The design enables dynamic absorption tuning via electrical and magnetic biassing. [ABSTRACT FROM AUTHOR]

Dynamic properties of ferromagnetic nematic liquid crystals under an external magnetic field have investigated. The coupled dynamics of the magnetization, M , and the director field, n , associated with the liquid crystalline orientation order, have studied. In the framework of the hydrodynamicand and thermodynamic approach, the role of the dynamic cross-coupling in macroscopic dynamic behavior both the nematic liquid crystal and its magneto-optic properties is considered. The dependence of the temporal evolution of a magneto-induced response on the dissipative and reversible parts of the dynamic cross-coupling is considered. [ABSTRACT FROM AUTHOR]

We present studies on the long-term reliability of interferometric fiber-optic current sensors (FOCS) for use in electric power transmission systems. Accelerated ageing tests are performed on crucial optical sensor components and a three-phase sensor system is subjected to an extended field trial. The sensor components under test include the sensor’s superluminescent light emitting diode light source, the integrated-optic phase modulator and various passive components such as fiber couplers, fiber polarizers, polarization-maintaining fiber connectors, and fiber coatings. The components are exposed to accelerated ageing conditions for extended periods of time, i.e., temperature cycling (between −25 °C and 65 °C for up to 15000 cycles), constant high temperature at dry conditions (up to 115 °C for up to 20000 h), and damp heat (85 % relative humidity at 85 °C for up to 7900 h). Crucial component parameters such as the source wavelength and polarization extinction ratios are repeatedly measured as a function of temperature at defined intervals during the ageing periods and examined for potential drift of component failures. The field trial is carried out for a three-phase FOCS system integrated into 420 kV double-chamber circuit breakers over a period of more than three years. The sensor signals are compared to the signals of conventional current transformers. In addition, the evolution of various operational parameters such as the light source power is continuously recorded. The results prove a high degree of reliability of modern FOCS systems. [ABSTRACT FROM AUTHOR]

We propose an arresting scheme for emulating the famous Faraday effect in ultracold atomic gases. Inspired by the similarities between the light field and bosonic atoms, we represent the light propagation in medium by the atomic transport in accompany of the laser-atom interaction. An artificial magneto-optic Faraday effect (MOFE) is readily signaled by the spin imbalance of atoms, with the setup of laser fields offering a high controllability for quantum manipulation. The present scheme is really feasible and can be realized with existing experimental techniques of ultracold atoms. It generalizes the crucial concept of the MOFE to ultracold atomic physics, and opens a new way of quantum emulating and exploring the MOFE and associated intriguing physics.

Magneto-induced molecular orientational transitions in nematic liquid crystals doped by ferromagnetic nanoparticles have studied. On the basis of a microscopic approach of tensor operators it is sequentially considered the influence of the ferromagnetic dopes on the sensitivity of the orientational structure and the optical activity of the nematic liquid crystals. [ABSTRACT FROM AUTHOR]

We demonstrate the selective control of the magnetic response and photoluminescence properties of Er 3 + centers with light, by associating them with a highly conjugated β -diketonate (1,3-di(2-naphthyl)-1,3-propanedione) ligand. We demonstrate this system to be an optically-pumped molecular compound emitting in infra-red, which can be employed as a precise heat-driving and detecting unit for low temperatures. • Control of the magnetic response of Er-molecular compound through light. • Close correlation between the magnetic response and absorption spectra. • Application as a contact-free, rare-earth-based thermometer for low temperatures. [ABSTRACT FROM AUTHOR]

In this paper, we study the spin-reorientation processes in DyCo5 and TbCo5 intermetallic compounds by direct observation of domain structure (DS) realignment during the easy plane—easy cone—easy axis phase transitions. In addition to the analysis of DS changes due to temperature induced spin reorientation, a description is given of a newly discovered effect of surface out-of-plane domain reorientation produced by abrasion and/or indentation of the surface of macroscopic samples with overall easy-plane magnetocrystalline anisotropy. [ABSTRACT FROM AUTHOR]

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The combination of the vector nature (i.e. polarization) of light in materials with nonlinearity can give rise to outstanding phenomena in the transmission of nonlinear optical fields. When the optical medium has been initially altered by a magnetic field, magneto-optical effects introduce additional interesting phenomena such as the possible control of optical signals by a magnetic field. The present work addresses the problem of optical-soliton generation from pulsed radiations interacting with a quasi-resonant magneto-optical medium, under normal Zeeman effect. It is shown that multi-soliton structures can be generated in the magneto-optical medium under specific conditions, these include periodic trains of bright and dark optical solitons having finite temporal periods. [ABSTRACT FROM AUTHOR]

This paper discusses the nonreciprocal effect induced by magnetized semiconductor substrate on surface plasmon mode guided through monolayer graphene. Dispersion relation for the fundamental antisymmetric mode is derived analytically. Nonreciprocal propagation characteristics of fundamental mode is studied as a function of wavelength, graphene layer chemical potential and biasing magnetic field. Fundamental mode exhibits appreciable nonreciprocal dispersion for transversal magnetization of semiconductor substrate in midinfrared and terahertz frequencies. Cutoff wavelength for backward propagating mode is observed above 2.5 T of external biasing field. Cutoff wavelength is found to be decreasing with increase in the biasing magnetic field and cladding index, also identified to be independent of graphene layer chemical potential. Proposed waveguide structure suggests the possibility of realizing one way propagating plasmonic waveguides with widely tunable guiding characteristics and related functional devices such as isolators, modulators, phase shifters and switches for integrated photonic circuits. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fiber optic sensors dispose of some advantages in the field of electrical current and magnetic field measurement, like large bandwidth, linearity, light transmission possibilities. Unfortunately, they suffer from some parasitic phenomena. The crucial issue is the presence of induced and latent linear birefringence, which is imposed by the fiber manufacture imperfections as well as mechanical stress by fiber bending. In order to the linear birefringence compensation a promising method was chosen for pulsed current sensor design. The method employs orthogonal polarization conjugation by the back direction propagation of the light wave in the fiber. The Jones calculus analysis presents its propriety. An experimental fiber optic current sensor has been designed and realized. The advantage of the proposed method was proved considering to the sensitivity improvement.

In the current study, we have explored the broadband absorption characteristics of graphene-layered random photonic crystals by the 4 × 4 characteristic matrix method. The findings confirm that under the influence of magnetic field B, optimal semi-random photonic crystals are capable of providing broadband absorption with a value greater than 84% in the wavelength range of 74.8–85.57 μm. The absorption band is tuned to desired frequencies by appropriate selection of the thickness of the silicon carbide layer. An absorption and FWHM enhancement with respect to the number of layers in each elementary unit, Fermi-level, and period number are numarically revealed. The application of a positive magnetic field minimises fluctuations and enhances the FWHM value in the desired absorption band for LCP waves, whereas the converse is true for RCP waves. The proposed absorber has applications in polarization selective absorbers, sensors and terahertz imaging. • A broadband Terahertz absorber designed with only a minimal number of graphene layers. • An absorption band is tuned to the desired frequencies by the appropriate selection thickness of the spacer layer. • The random structures have more potential to provide broadband absorption compared to periodic structures. • The anisotropic property of graphene plays a crucial role in reducing fluctuations in a selected absorption band. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the total reflection tunneling effect of the one-dimensional (1-D) photonic crystal, the multi-channel filter structure is proposed, in which SiO 2 –ferrite–TiO 2 structure layer is introduced into the photonic crystal as the compound defect. The total reflection tunneling phenomena is analyzed using the transfer matrix method, and the influence on the tunneling mode by the number of compound defect, the number of the periodical structure layer, the optical thickness of the defect layer, and the variation of magnetic intensity are discussed, respectively. The magneto-optical properties of the ferrite defect layer are analyzed and the changing regularity of the transmission spectrum for the photonic crystal is obtained with the modulation of the external magnetic field. The simulation results show that the number of tunneling modes is corresponding to the number of the compound defects, and the full width with half magnitude (FWHM) of the tunneling modes will be narrowed with the increase of the number for the compound defects and the quality factor can attain to 1974.9, which can achieve ultra-narrowband multi-channel filtering. When the external magnetic intensity changes, the transmission spectrum will shift with the sensitivity of 198.7 nm/RIU. The photonic crystal filter is compact in structure and has perfect tunability, which can provide some theoretical references for the design of high Q value and tunable multi-channel photonic crystal filters. [ABSTRACT FROM AUTHOR]

Starting with the nonlinear coupled-mode equations of guided optical waves in the magneto-optic fiber Bragg grating (MFBG), the amplitude transfer curve of the transmitted light is numerically calculated for the incident right-circularly polarized wave, and the multi-stability is analyzed by introducing the parameter of jitter suppression. It is shown that, (i) the performance of amplitude jitter suppression in the stable states of high level is better than that of low level; (ii) the jitter suppression in the multi-stable regions can be enhanced when the magnetic field is applied to the MFBG in the opposite direction of the incident wave; and (iii) by adjusting the applied magnetic field, the multi-stable levels can be tuned flexibly, which is helpful for developing the intelligent all-optical devices for multilevel regeneration. [ABSTRACT FROM AUTHOR]

Highlights: [•] We report the synthesis of a novel polysquaraine. [•] Prepared disks of the polysquaraine display large magneto-optic effects. [•] Disk samples also return saturation magnetization values of 4.13×10−3 emug−1. [•] All observations are commensurate with magnetism of a reduced dimensional nature. [ABSTRACT FROM AUTHOR]

Abstract: We present temperature-dependent magneto-optic hysteresis curves of “quasi-two-dimensional” arrays of 10nm Co nanoparticles which are covered by a native CoO layer. The particles deposited on thin aluminum films become magnetically very hard at 10K, i.e. the coercive field exceeds 1.6T. Only in a narrow temperature range near 100K an out-of-plane magnetization loop with considerable coercivity is observed. A shift of the magneto-optic hysteresis curves due to exchange bias was detected. Magnetization measurements on a frozen volume of nanoparticle solution reveal a strong exchange-bias effect of 0.8T at 10K. The exchange-bias effect is attributed to the rough interface and/or spin-disordered state between CoO shell and Co core. [Copyright &y& Elsevier]

Fiber optic sensors dispose of some advantages in the field of electrical current and magnetic field measurement, like large bandwidth, linearity, light transmission possibilities. Unfortunately, they suffer from some parasitic phenomena. The crucial issue is the presence of induced and latent linear birefringence, which is imposed by the fiber manufacture imperfections as well as mechanical stress by fiber bending. In order to the linear birefringence compensation a promising method was chosen for pulsed current sensor design. The method employs orthogonal polarization conjugation by the back direction propagation of the light wave in the fiber. The Jones calculus analysis presents its propriety. An experimental fiber optic current sensor has been designed and realized. The advantage of the proposed method was proved considering to the sensitivity improvement. [ABSTRACT FROM AUTHOR]

Using the macroscopic formalism of the Kerr Effect, the magneto-optical (MO) response of (Cox/Pdx)n and (Cox/Ptx)n multilayers was simulated while varying x (monolayer thickness) and n its periodicity . Later the MO response of the same multilayers was simulated with Pd and Pt cov-ers. With the variation of those parameters the MO effects Faraday-Kerr transition (TF-K) is ob-served. It is shown a TF-K surface as a function of those parameters. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)