Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections

Rémi Faggiani; Alexandre Baron; Xiaorun Zang; Loïc Lalouat; Sebastian A. Schulz; Bryan O'Regan; Kevin Vynck; Benoît Cluzel; Frédérique De Fornel; Thomas F. Krauss; Philippe Lalanne

doi:10.1038/srep27037

Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections

Rémi Faggiani, Alexandre Baron^*, Xiaorun Zang, Loïc Lalouat, Sebastian A. Schulz, Bryan O'Regan, Kevin Vynck, Benoît Cluzel, Frédérique De Fornel, Thomas F. Krauss, Philippe Lalanne

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

Light localization due to random imperfections in periodic media is paramount in photonics research. The group index is known to be a key parameter for localization near photonic band edges, since small group velocities reinforce light interaction with imperfections. Here, we show that the size of the smallest localized mode that is formed at the band edge of a one-dimensional periodic medium is driven instead by the effective photon mass, i.e. the flatness of the dispersion curve. Our theoretical prediction is supported by numerical simulations, which reveal that photonic-crystal waveguides can exhibit surprisingly small localized modes, much smaller than those observed in Bragg stacks thanks to their larger effective photon mass. This possibility is demonstrated experimentally with a photonic-crystal waveguide fabricated without any intentional disorder, for which near-field measurements allow us to distinctly observe a wavelength-scale localized mode despite the smallness (∼1/1000 of a wavelength) of the fabrication imperfections.

Original language	English
Article number	27037
Journal	Scientific Reports
Volume	6
Early online date	1 Jun 2016
DOIs	https://doi.org/10.1038/srep27037
Publication status	E-pub ahead of print - 1 Jun 2016

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Scientific reports 27037Final published version, 706 KBLicence: CC BY

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title = "Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections",

abstract = "Light localization due to random imperfections in periodic media is paramount in photonics research. The group index is known to be a key parameter for localization near photonic band edges, since small group velocities reinforce light interaction with imperfections. Here, we show that the size of the smallest localized mode that is formed at the band edge of a one-dimensional periodic medium is driven instead by the effective photon mass, i.e. the flatness of the dispersion curve. Our theoretical prediction is supported by numerical simulations, which reveal that photonic-crystal waveguides can exhibit surprisingly small localized modes, much smaller than those observed in Bragg stacks thanks to their larger effective photon mass. This possibility is demonstrated experimentally with a photonic-crystal waveguide fabricated without any intentional disorder, for which near-field measurements allow us to distinctly observe a wavelength-scale localized mode despite the smallness (∼1/1000 of a wavelength) of the fabrication imperfections.",

author = "R{\'e}mi Faggiani and Alexandre Baron and Xiaorun Zang and Lo{\"i}c Lalouat and Schulz, {Sebastian A.} and Bryan O'Regan and Kevin Vynck and Beno{\^i}t Cluzel and {De Fornel}, Fr{\'e}d{\'e}rique and Krauss, {Thomas F.} and Philippe Lalanne",

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doi = "10.1038/srep27037",

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T1 - Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections

AU - Faggiani, Rémi

AU - Baron, Alexandre

AU - Zang, Xiaorun

AU - Lalouat, Loïc

AU - Schulz, Sebastian A.

AU - O'Regan, Bryan

AU - Vynck, Kevin

AU - Cluzel, Benoît

AU - De Fornel, Frédérique

AU - Krauss, Thomas F.

AU - Lalanne, Philippe

PY - 2016/6/1

Y1 - 2016/6/1

N2 - Light localization due to random imperfections in periodic media is paramount in photonics research. The group index is known to be a key parameter for localization near photonic band edges, since small group velocities reinforce light interaction with imperfections. Here, we show that the size of the smallest localized mode that is formed at the band edge of a one-dimensional periodic medium is driven instead by the effective photon mass, i.e. the flatness of the dispersion curve. Our theoretical prediction is supported by numerical simulations, which reveal that photonic-crystal waveguides can exhibit surprisingly small localized modes, much smaller than those observed in Bragg stacks thanks to their larger effective photon mass. This possibility is demonstrated experimentally with a photonic-crystal waveguide fabricated without any intentional disorder, for which near-field measurements allow us to distinctly observe a wavelength-scale localized mode despite the smallness (∼1/1000 of a wavelength) of the fabrication imperfections.

AB - Light localization due to random imperfections in periodic media is paramount in photonics research. The group index is known to be a key parameter for localization near photonic band edges, since small group velocities reinforce light interaction with imperfections. Here, we show that the size of the smallest localized mode that is formed at the band edge of a one-dimensional periodic medium is driven instead by the effective photon mass, i.e. the flatness of the dispersion curve. Our theoretical prediction is supported by numerical simulations, which reveal that photonic-crystal waveguides can exhibit surprisingly small localized modes, much smaller than those observed in Bragg stacks thanks to their larger effective photon mass. This possibility is demonstrated experimentally with a photonic-crystal waveguide fabricated without any intentional disorder, for which near-field measurements allow us to distinctly observe a wavelength-scale localized mode despite the smallness (∼1/1000 of a wavelength) of the fabrication imperfections.

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VL - 6

JO - Scientific Reports

JF - Scientific Reports

M1 - 27037

ER -

Lower bound for the spatial extent of localized modes in photonic-crystal waveguides with small random imperfections

Abstract

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