scholarly journals Optical lattice with spin-dependent sub-wavelength barriers

2021 ◽  
Vol 11 (6) ◽  
Author(s):  
Edvinas Gvozdiovas ◽  
Povilas Račkauskas ◽  
Gediminas Juzeliūnas
Keyword(s):  
Tight Binding ◽  
Coupling Scheme ◽  
Brick Wall ◽  
Laser Fields ◽  
Dark State ◽  
Coupling Laser ◽  
Spin Ordering ◽  
Light Coupling ◽  
Type Lattice ◽  
Sub Wavelength

We analyze a tripod atom light coupling scheme characterized by two dark states playing the role of quasi-spin states. It is demonstrated that by properly configuring the coupling laser fields, one can create a lattice with spin-dependent sub-wavelength barriers. This allows to flexibly alter the atomic motion ranging from atomic dynamics in the effective brick-wall type lattice to free motion of atoms in one dark state and a tight binding lattice with a twice smaller periodicity for atoms in the other dark state. Between the two regimes, the spectrum undergoes significant changes controlled by the laser fields. The tripod lattice can be produced using current experimental techniques. The use of the tripod scheme to create a lattice of degenerate dark states opens new possibilities for spin ordering and symmetry breaking.

scholarly journals Efficient light coupling into in-plane semiconductor nanomembrane photonic devices utilizing a sub-wavelength grating coupler

2012 ◽  
Vol 20 (18) ◽  
pp. 20659 ◽  
Author(s):  
Harish Subbaraman ◽  
Xiaochuan Xu ◽  
John Covey ◽  
Ray T. Chen
Keyword(s):  
Photonic Devices ◽  
Grating Coupler ◽  
Light Coupling ◽  
Sub Wavelength

scholarly journals Light-coupling masks for lensless, sub-wavelength optical lithography

1998 ◽  
Vol 72 (19) ◽  
pp. 2379-2381 ◽  
Author(s):  
Heinz Schmid ◽  
Hans Biebuyck ◽  
Bruno Michel ◽  
Olivier J. F. Martin
Keyword(s):  
Optical Lithography ◽  
Light Coupling ◽  
Sub Wavelength

CORRUGATED QUANTUM WELL INFRARED PHOTODETECTORS AND ARRAYS

2002 ◽  
Vol 12 (03) ◽  
pp. 715-759 ◽  
Author(s):  
K. K. CHOI
Keyword(s):  
Quantum Well ◽  
Material Characterization ◽  
Infrared Detection ◽  
Infrared Photodetectors ◽  
Coupling Scheme ◽  
Electromagnetic Modeling ◽  
Material Technology ◽  
Quantum Well Infrared Photodetectors ◽  
Light Coupling

Quantum well infrared photodetectors (QWIPs) have many advantages in infrared detection, mainly due to the mature III-V material technology. The employment of the corrugated light-coupling scheme further improves the technology for its simplicity and efficiency. A C-QWIP enjoys the same flexibility as a detector with intrinsic normal incident absorption. In this chapter, we will discuss the sensitivity of C-QWIPs and their utilities in infrared detection, material characterization and electromagnetic modeling. Besides the standard corrugated structures, other exploratory detector architectures will also be described.

scholarly journals Ultimate conversion efficiency bound for the forward double-Λ atom–light coupling scheme

2020 ◽  
Vol 45 (21) ◽  
pp. 6090
Author(s):  
Dionisis Stefanatos ◽  
Athanasios Smponias ◽  
Hamid Reza Hamedi ◽  
Emmanuel Paspalakis
Keyword(s):  
Conversion Efficiency ◽  
Coupling Scheme ◽  
Light Coupling

scholarly journals Enhanced light coupling in sub-wavelength single-mode silicon on insulator waveguides

2009 ◽  
Vol 17 (9) ◽  
pp. 6939 ◽  
Author(s):  
C. Pang ◽  
F. Gesuele ◽  
A. Bruyant ◽  
S. Blaize ◽  
G. Lérondel ◽  
...  
Keyword(s):  
Single Mode ◽  
Silicon On Insulator ◽  
Light Coupling ◽  
Sub Wavelength

scholarly journals Possible Routes to Obtain Enhanced Magnetoresistance in a Driven Quantum Heterostructure with a Quasi-Periodic Spacer

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1021
Author(s):  
Arpita Koley ◽  
Santanu K. Maiti ◽  
Laura M. Pérez ◽  
Judith Helena Ojeda Silva ◽  
David Laroze
Keyword(s):  
Layered Structure ◽  
Numerical Study ◽  
Tight Binding ◽  
Light Irradiation ◽  
Effect Of Temperature ◽  
Coupling Scheme ◽  
Magnetic Layers ◽  
Periodic Potentials ◽  
Ferromagnetic Layers ◽  
Multilayered Systems

In this work, we perform a numerical study of magnetoresistance in a one-dimensional quantum heterostructure, where the change in electrical resistance is measured between parallel and antiparallel configurations of magnetic layers. This layered structure also incorporates a non-magnetic spacer, subjected to quasi-periodic potentials, which is centrally clamped between two ferromagnetic layers. The efficiency of the magnetoresistance is further tuned by injecting unpolarized light on top of the two sided magnetic layers. Modulating the characteristic properties of different layers, the value of magnetoresistance can be enhanced significantly. The site energies of the spacer is modified through the well-known Aubry–André and Harper (AAH) potential, and the hopping parameter of magnetic layers is renormalized due to light irradiation. We describe the Hamiltonian of the layered structure within a tight-binding (TB) framework and investigate the transport properties through this nanojunction following Green’s function formalism. The Floquet–Bloch (FB) anstaz within the minimal coupling scheme is introduced to incorporate the effect of light irradiation in TB Hamiltonian. Several interesting features of magnetotransport properties are represented considering the interplay between cosine modulated site energies of the central region and the hopping integral of the magnetic regions that are subjected to light irradiation. Finally, the effect of temperature on magnetoresistance is also investigated to make the model more realistic and suitable for device designing. Our analysis is purely a numerical one, and it leads to some fundamental prescriptions of obtaining enhanced magnetoresistance in multilayered systems.

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