Two-dimensional array of iron-garnet nanocylinders supporting localized and lattice modes for the broadband boosted magneto-optics.

We demonstrate a novel all-dielectric magnetophotonic structure that consists of two-dimensional arrays of bismuth substituted iron-garnet nanocylinders supporting both localized (Fabry-Perot-like) and lattice (guided-like) optical modes. Simultaneous excitation of the two kinds of modes provides a significant enhancement of the Faraday effect by 3 times and transverse magneto-optical Kerr effect by an order of magnitude compared to the smooth magnetic film of the same effective thickness. Both magneto-optical effects are boosted in wide spectral and angular ranges making the nanocylinder array magnetic dielectric structures promising for applications with short and tightly focused laser pulses.

Magnetless Optical Circulator Based on an Iron Garnet with Reduced Magnetization Saturation.

A three-port circulator for optical communication systems comprising a photonic crystal slab made of a magneto-optical material in which an magnetizing element is not required to keep its magnetic domains aligned is suggested for the first time. By maximizing the incorporation of europium to its molecular formula, the magneto-optical material can remain in the saturated magnetic state even in the absence of an external DC magnetic field. Two- and three-dimensional simulations of the device performed with full-wave electromagnetic solvers based on the finite element method demonstrate that, at the 1550 nm wavelength, the insertion loss, isolation, and reflection levels are equal to or better than -1 dB, -14 dB, and -20 dB, respectively.

Magneto-optics of subwavelength all-dielectric gratings.

We provide the experimental research on a novel type of all-dielectric magnetic structure designed to achieve an enhanced magneto-optical response. 1D grating fabricated via etching of bismuth substituted iron garnet film supports the excitation of optical guided modes, which are highly sensitive to the external magnetic field. A unique feature of proposed structure is the synergetic combination of high transparency, tunability, high Q-factor of the resonances and superior magneto-optical response that is two orders higher in magnitude than in the non-structured smooth iron-garnet film.

Nonreciprocal Transverse Photonic Spin and Magnetization-Induced Electromagnetic Spin-Orbit Coupling.

We present a formulation of electromagnetic spin-orbit coupling in magneto-optic media, and propose an alternative source of spin-orbit coupling to non-paraxial optics vortices. Our treatment puts forth a formulation of nonreciprocal transverse-spin angular-momentum-density shifts for evanescent waves in magneto-optic waveguide media. It shows that magnetization-induced electromagnetic spin-orbit coupling is possible, and that it leads to unequal spin to orbital angular momentum conversion in magneto-optic media evanescent waves in opposite propagation-directions.

Optical isolation in topological-edge-state photonic arrays.

We introduce a new type of optical isolator based on breaking time reversal symmetry in dissipative finite Su-Schrieffer-Heeger (SSH) waveguide arrays that support topological edge states at one end of the structure. In the forward propagation direction, light is launched into the edge waveguide to excite the localized topological midgap state. As a result, most of the input optical power is transmitted to the output port.

Enhancing optical isolator performance in nonreciprocal waveguide arrays.

We investigate the operation of optical isolators based on magneto-optics waveguide arrays beyond the coupled mode analysis. Semi-vectorial beam propagation simulations demonstrate that evanescent tail coupling and the effects of radiation are responsible for degrading the device's performance. Our analysis suggests that these effects can be mitigated when the array size is scaled up.

On-chip optical isolation based on nonreciprocal resonant delocalization effects.

We propose on-chip optical isolators that provide large isolation ratios. The isolation mechanism is based on the interplay between magneto-optical effects and resonant delocalization. Our analysis predicts large isolation ratios in the range of -45 to -55 dB between forward and backward propagating optical beams.

On-chip optical isolation via unidirectional Bloch oscillations in a waveguide array.

We propose to use the unidirectionality of the optical Bloch oscillation phenomenon achievable in a magneto-optic asymmetric waveguide array to achieve optical isolation. At the 1.55 μm telecommunication wavelength, our isolator design exhibits an isolation ratio of 36 dB between forward- and backward-propagating waves.

Formation of Degenerate Band Gaps in Layered Systems.

In the review, peculiarities of spectra of one-dimensional photonic crystals made of anisotropic and/or magnetooptic materials are considered. The attention is focused on band gaps of a special type-the so called degenerate band gaps which are degenerate with respect to polarization. Mechanisms of formation and properties of these band gaps are analyzed.

Unidirectional optical Bloch oscillations in asymmetric waveguide arrays.

We present an analytical proof of the existence of unidirectional optical Bloch oscillations in a waveguide array system. It is shown that the presence of nonreciprocity in the system allows for a complete normal-mode dephasing in one of the propagation directions, resulting in a unidirectional breakdown in Bloch oscillations. A model system consisting of an array of transversely magnetized asymmetric Si/SiO2 waveguides with a magneto-optic cover layer is presented.

Nonreciprocal Bloch oscillations in magneto-optic waveguide arrays.

We show that nonreciprocal optical Bloch-like oscillations can emerge in transversely magnetized waveguide arrays in the presence of an effective index step between the waveguides. Normal modes of the system are shown to acquire different wavenumbers in opposite propagation directions. Significant differences in phase coherence and decoherence between these normal modes are presented and discussed.

Second harmonic generation study of internally-generated strain in bismuth-substituted iron garnet films.

The present article highlights the lattice-imperfection and compositional origins of the nonlinear optical response in bismuth-substituted iron garnet films. In particular the roles of lattice mismatch strain and micro-strain on second harmonic generation in (Bi,Y)(3)(Fe,Ga)(5)O(12) films are elucidated based on experimental findings. It is found that lattice mismatch strain drives the second harmonic signal in (Bi,Y)(3)(Fe,Ga)(5)O(12) films, in agreement with theoretical predictions; however micro-strain was found not to correlate significantly with the second harmonic signal at the micro-strain levels present in these samples.

Bandgap formation and selective suppression of Bloch states in birefringent gyrotropic Bragg waveguides.

Birefringent magnetophotonic crystals are found to exhibit degeneracy breaking for asymmetric contradirectional coupling in planar waveguides. Fundamental to high-order local normal mode coupling leads to partially overlapping gyrotropic bandgaps inside the Brillouin zone and partial suppression of Bloch mode propagation. A large magneto-optically active reorientation in polarization state is found for allowed Bloch modes at bandgap edges.

Single-crystal relaxor ferroelectric piezoactuators with interdigitated electrodes.

We report on the fabrication and performance of (1-x) Pb(Zn(1/3)Nb(2/3))O3-xPbTiO3 (PZN-PT) single-crystal relaxor piezoactuators with interdigitated electrodes patterned on a single surface. An electric field gradient across the sample thickness induces a differential contraction between opposite faces, and it is responsible for the actuation. The samples are poled by energizing the electrodes at 100 degrees C and cooling in a field.