Local Normal Mode Coupling and Energy Band Splitting in Elliptically Birefringent 1D Magnetophotonic Crystals

An analysis is presented of wave-vector dispersion in elliptically birefringent stratified magneto-optic media having one-dimensional periodicity. It is found that local normal-mode polarization-state differences between adjacent layers lead to mode coupling and impact the wave-vector dispersion and the character of the Bloch states of the system. This coupling produces extra terms in the dispersion relation not present in uniform circularly birefringent magneto-optic stratified media. Normal mode coupling lifts the degeneracy at frequency band cross-over points under certain conditions and induces a magnetization-dependent optical band gap. This study examines the conditions for band gap formation in the system. It shows that such a frequency-split can be characterized by a simple coupling parameter that depends on the relation between polarization states of local normal modes in adjacent layers. The character of the Bloch states and conditions for maximizing the strength of the band splitting in these systems are analyzed.Comment: 15 pages, 4 figure

Magneto-photonic crystal isolators

A magneto-optical isolator (20) for an optical circuit. The isolator includes a substrate, and an optical channel (350) disposed next to the substrate. The optical channel and substrate are configured to transmit optical radiation within the optical channel. The isolator further includes a photonic- crystal rotator (24) formed with the substrate and the optical channel. The rotator has at least one defect (52) and magnetic (M) and non-magnetic (N) materials.https://digitalcommons.mtu.edu/patents/1045/thumbnail.jp

Managing Systemic Liquidity Risk in Financially Dollarized Economy

This paper evaluates ways to protect highly dollarized banking systems from systemic liquidity runs (such as the ones that took place recently in Argentina, Uruguay, and Paraguay). In view of the limitations of available (private or official) insurance schemes, and the distortions introduced by central bank lending of last resort (LOLR), the authors favor decentralized liquid foreign asset requirements on dollar deposits, supplemented by a scheme of “circuit breakers.” The latter combines the use of limited dollar liquidity to ensure the convertibility of transactional deposits with a mechanism that automatically limits the convertibility of dollar term deposits once triggered by a predetermined decline in banks’ liquidity.

Band structure and Bloch states in birefringent 1D magnetophotonic crystals: An analytical approach

An analytical formulation for the band structure and Bloch modes in elliptically birefringent magnetophotonic crystals is presented. The model incorporates both the effects of gyrotropy and linear birefringence generally present in magneto-optic thin film devices. Full analytical expressions are obtained for the dispersion relation and Bloch modes in a layered stack photonic crystal and their properties are analyzed. It is shown that other models recently discussed in the literature are contained as special limiting cases of the formulation presented herein

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

A study of nonreciprocal transverse-spin angular-momentum-density shifts for evanescent waves in magneto-optic waveguide media is presented. Their functional relation to electromagnetic spin- and orbital-momenta is presented and analyzed. It is shown that the magneto-optic gyrotropy can be re-interpreted as the nonreciprocal electromagnetic spin-density shift per unit energy flux, thus providing an interesting alternative physical picture for the magneto-optic gyrotropy. The transverse spin-density shift is found to be thickness-dependent in slab optical waveguides. This dependence is traceable to the admixture of minority helicity components in the transverse spin angular momentum. It is also shown that the transverse spin is magnetically tunable. A formulation of electromagnetic spin-orbit coupling in magneto-optic media is presented, and an alternative source of spin-orbit coupling to non-paraxial optics vortices is proposed. It is shown that magnetization-induced electromagnetic spin-orbit coupling is possible, and that it leads to spin to orbital angular momentum conversion in magneto-optic media evanescent waves.Comment: 11 pages, 4 figures In this second version, I have added an explicit expression for the spin-orbit coupling at the end of the articl