First principles calculation of topological invariants of non-Hermitian photonic crystals

AbstractTopological photonic systems have recently emerged as an exciting new paradigm to guide light without back-reflections. The Chern topological numbers of a photonic platform are usually written in terms of the Berry curvature, which depends on the normal modes of the system. Here, we use a gauge invariant Green’s function method to determine from first principles the topological invariants of photonic crystals. The proposed formalism does not require the calculation of the photonic band-structure, and can be easily implemented using the operators obtained with a standard plane-wave expansion. Furthermore, it is shown that the theory can be readily applied to the classification of topological phases of non-Hermitian photonic crystals with lossy or gainy materials, e.g., parity-time symmetric photonic crystals.

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3-D Photonic Band Structure Engineering in Self-Assembled Macroporous Photonic Crystals

MRS Proceedings ◽

10.1557/proc-988-0988-qq05-08 ◽

2006 ◽

Vol 988 ◽

Author(s):

Michael H. Bartl ◽

Kaycee Carter ◽

Michael H. Bartl

Keyword(s):

Experimental Data ◽

Photonic Crystals ◽

Band Structure ◽

Photonic Band Structure ◽

Crystal Axis ◽

Inverse Opals ◽

Band Structure Calculations ◽

Structure Engineering ◽

Photonic Band ◽

Structure Calculations

AbstractBy applying directional pressure along the (111) crystal axis of opaline photonic crystals under controlled temperatures, inverse opals with symmetry broken structures are fabricated. This selective deformation results in strongly modified photonic band structures and hence optical properties of the photonic crystals. Experimental data are accompanied by theoretical band structure calculations that confirm the experimental results and are used to predict new structures with optimized band gap properties.

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Exciton Polaritons in One-Dimensional Metal-Semiconductor Photonic Crystals

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18429 ◽

2008 ◽

Vol 8 (12) ◽

pp. 6584-6588 ◽

Cited By ~ 3

Author(s):

R. Márquez-Islas ◽

B. Flores-Desirena ◽

F. Pérez-Rodríguez

Keyword(s):

Photonic Crystal ◽

Photonic Crystals ◽

Band Structure ◽

Dielectric Function ◽

Low Frequency ◽

Photonic Band Structure ◽

One Dimensional ◽

Exciton Polaritons ◽

Metal Layers ◽

Photonic Band

We investigate theoretically the coupling of exciton with light in a one-dimensional photonic crystal. The unit cell of the crystal consists of two alternating layers, namely a metallic layer and a semiconductor one. The frequency-dependent dielectric function of the metal is described by the Drude model, whereas for the semiconductor we use a nonlocal excitonic dielectric function. The polariton dispersion for s-polarized modes in the metal-semiconductor photonic crystal is compared with that for a dielectric-semiconductor photonic crystal. Because of the metal layers, a low-frequency gap appears in the photonic band structure. The presence of the semiconductor gives rise to photonic bands associated with the coupling of light with size-quantized excitón states. At frequencies above the longitudinal exciton frequency, the photonic band structure exhibits anticrossing phenomena produced by the upper exciton–polariton mode and size-quantized excitons. It is found that the anticrossing phenomena in the metal-semiconductor photonic crystal occur at higher frequencies in comparison with the dielectric-semiconductor case.

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Iridescence and spectral filtering of the gyroid-type photonic crystals in Parides sesostris wing scales

Interface Focus ◽

10.1098/rsfs.2011.0082 ◽

2011 ◽

Vol 2 (5) ◽

pp. 681-687 ◽

Cited By ~ 51

Author(s):

Bodo D. Wilts ◽

Kristel Michielsen ◽

Hans De Raedt ◽

Doekele G. Stavenga

Keyword(s):

Spatial Distribution ◽

Photonic Crystals ◽

Reflectance Spectrum ◽

Green Light ◽

Wing Pattern ◽

Photonic Band Structure ◽

Spectral Filtering ◽

Pass Filter ◽

Photonic Band ◽

Wing Scales

The cover scales on the wing of the Emerald-patched Cattleheart butterfly, Parides sesostris , contain gyroid-type biological photonic crystals that brightly reflect green light. A pigment, which absorbs maximally at approximately 395 nm, is immersed predominantly throughout the elaborate upper lamina. This pigment acts as a long-pass filter shaping the reflectance spectrum of the underlying photonic crystals. The additional effect of the filtering is that the spatial distribution of the scale reflectance is approximately angle-independent, leading to a stable wing pattern contrast. The spectral tuning of the original reflectance is verified by photonic band structure modelling.

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