Anderson Localization in Disordered LN Photonic Crystal Slab Cavities

Abstract

We present a detailed theoretical study of the effects of structural disorder on LN photonic crystal slab cavities, ranging from short to long length scales (N =3-35 cavity lengths), using a fully three-dimensional Bloch mode expansion technique. We compute the optical density of states (DOS), quality factors and effective mode volumes of the cavity modes, with and without disorder, and compare with the localized modes of the corresponding disordered photonic crystal waveguide. We demonstrate how the quality factors and effective mode volumes saturate at a specific cavity length and become bounded by the corresponding values of the Anderson modes appearing in the disordered waveguide. By means of the intensity fluctuation criterion, we observe Anderson-like localization for cavity lengths larger than around L31, and show that the field confinement in the disordered LN cavities is mainly determined by the local characteristics of the structural disorder as long as the confinement region is far enough from the cavity mirrors and the effective mode localization length is much smaller than the cavity length; under this regime, the disordered cavity system becomes insensitive to changes in the cavity boundaries and a good agreement with the intensity fluctuation criterion is found for localization. Surprisingly, we find that the Anderson-like localized

Global optimization of an encapsulated Si/SiO2 L3 cavity with a 43 million quality factor

“…These features have allowed to study a wide variety of classical and quantum phenomena, where the linear and non-linear interactions between light and matter are effectively enhanced in the cavity region [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . Broadly speaking, the strength of this enhancement grows with the local density of electromagnetic states, which is proportional to the quality factor of the cavity mode Q c , and inversely proportional to its mode volume V [21][22][23] . Hence, massive efforts have been directed toward the optimization of these figures of merit in order to reach the desired functionality of the photonic device [24][25][26][27][28][29] .…”

Global optimization of an encapsulated Si/SiO$$_2$$ L3 cavity with a 43 million quality factor

“…These features have allowed to study a wide variety of classical and quantum phenomena, where the linear and non-linear interactions between light and matter are effectively enhanced in the cavity region 3 – 20 . Broadly speaking, the strength of this enhancement grows with the local density of electromagnetic states, which is proportional to the quality factor of the cavity mode , and inversely proportional to its mode volume V 21 – 23 . Hence, massive efforts have been directed toward the optimization of these figures of merit in order to reach the desired functionality of the photonic device 24 – 29 .…”

Influence of disorder on a Bragg microcavity

“…Unavoidable technological imperfections can sometimes critically reduce the desired performance of photonic crystal slab waveguides and nanocavities [6][7][8][9]. Different theoretical approaches have been proposed to describe the role of disorder, either numerically [10,11] or based on various versions of perturbation theory in electrodynamics [6,[12][13][14][15]. The important prerequisite for any perturbation theory is a suitable basis, which, in the case of open electrodynamical systems, is composed of resonant states (also known as quasi-normal or leaky modes) [16][17][18][19][20][21][22][23][24][25][26][27] that determine the resonant optical response, e.g., the Fano resonances in open cavities [28][29][30].…”