Engineering gratings for light trapping in photovoltaics: The supercell concept

Martins, Emiliano R.; Li, Juntao; Liu, Yikun; Zhou, Jianying; Krauss, Thomas F.

doi:10.1103/physrevb.86.041404

Cited by 98 publications

(80 citation statements)

References 18 publications

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“…The latter is more common for optical device applications of interest here. Also note that the structures considered in this study resemble an insulator with hoppingtype transport and are better described on the basis of individual waveguide modes rather than periodic Bloch modes 27,47 .…”

Section: Discussionmentioning

confidence: 99%

High-density waveguide superlattices with low crosstalk

et al. 2015

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Silicon photonics holds great promise for low-cost large-scale photonic integration. In its future development, integration density will play an ever-increasing role in a way similar to that witnessed in integrated circuits. Waveguides are perhaps the most ubiquitous component in silicon photonics. As such, the density of waveguide elements is expected to have a crucial influence on the integration density of a silicon photonic chip. A solution to highdensity waveguide integration with minimal impact on other performance metrics such as crosstalk remains a vital issue in many applications. Here, we propose a waveguide superlattice and demonstrate advanced superlattice design concepts such as interlacing-recombination that enable high-density waveguide integration at a half-wavelength pitch with low crosstalk. Such waveguide superlattices can potentially lead to significant reduction in on-chip estate for waveguide elements and salient enhancement of performance for important applications, opening up possibilities for half-wavelength-pitch optical-phased arrays and ultra-dense space-division multiplexing.

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Section: Discussionmentioning

confidence: 99%

High-density waveguide superlattices with low crosstalk

et al. 2015

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“…In order to enhance light absorption, this type of solar cell employs nanostructures to couple light into the quasi-guided modes of its thin absorbing film 1,13,14,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] . The quasi-guided modes are usually excited by wavelength-scale periodic structures such as nano-wires 30,31 , photonic crystals [20][21][22][23][24][25][26][27][28][29] or metallic gratings 32,34 . The excitation of a quasi-guided mode results in strong resonant absorption enhancement, but only over a narrow bandwidth.…”

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confidence: 99%

“…The quasi-random cell of Fig. 2c offers a 'sweet-spot' in-between periodic and random domains by taking advantage of both; more resonances can be excited by its mesoscopic unit cell than by a wavelength-scale unit cell, yet these resonances are still strong because the modulation is designed to channel the diffracted energy only into the diffraction orders that can excite quasi-guided modes 29 .…”

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confidence: 99%

Deterministic quasi-random nanostructures for photon control

et al. 2013

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Controlling the flux of photons is crucial in many areas of science and technology. Artificial materials with nano-scale modulation of the refractive index, such as photonic crystals, are able to exercise such control and have opened exciting new possibilities for light manipulation. An interesting alternative to such periodic structures is the class of materials known as quasi-crystals, which offer unique advantages such as richer Fourier spectra. Here we introduce a novel approach for designing such richer Fourier spectra, by using a periodic structure that allows us to control its Fourier components almost at will. Our approach is based on binary gratings, which makes the structures easy to replicate and to tailor towards specific applications. As an example, we show how these structures can be employed to achieve highly efficient broad-band light trapping in thin films that approach the theoretical (Lambertian) limit, a problem of crucial importance for photovoltaics.

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“…Through different photonic architectures it is possible to augment the optical absorption by, for instance, trapping light within ultra-thin films [14], or even manipulate the photon density of state [15] or slowing down light in absorbing thin films. This can be achieved by periodic photonic structures [14,15] or disordered ones [19][20][21], as it has been recently proposed in a two-dimensional system [22] in which disorder modes are on the verge of light (Anderson) localization [23][24][25].…”

Section: -Introductionmentioning

confidence: 99%