Influence of fabrication disorder on the optical properties of coupled-cavity photonic crystal waveguides
Influence of fabrication disorder on the optical properties of coupled-cavity photonic crystal waveguides
复制标题
DOI：
10.1103/physrevb.78.144201
复制
发表时间：
2008-10-01
影响因子：
3.7
通讯作者：
Dignam, M. M.
中科院分区：
文献类型：
--
作者：
Fussell, D. P.;Hughes, S.;Dignam, M. M.
采用紧束缚的形式主义和微扰理论，我们从理论上证明了如何弱制造无序由于表面粗糙度显着降低半导体光子晶体板的耦合腔波导的带边性能。我们发现，表面粗糙度在很大程度上影响的带边性能，通过引入随机变化的个别腔频率，欧米茄（0），而不是通过变化的紧束缚耦合系数，卡帕。使用与最先进结构相当的模型粗糙度参数，估计Omega（0）的标准偏差为大于或接近1x 10（-4）Omega（0）的sigma（Omega 0）。发现高折射率对比度制造缺陷加宽了带边处的光子态密度，其特征线宽γ（e）近似于sigma（4/3）（omega 0）/（2 Omega（0）kappa）（1/3）。这意味着最小带边群速度约为v（g），类似于c/120，与实验一致。对于修改后的自发辐射的应用程序，我们表明，特征线宽γ（e）是，不幸的是，一个因素5大于最大的带边耦合率，强光子量子点带边相互作用可以发生。尽管在无序的情况下仍然可以实现大的珀塞尔因子，但是嵌入的半导体量子点随后耦合到有损（无序诱导）传播模式，这可能限制相干量子光学的潜在应用。
Employing a tight-binding formalism and perturbation theory, we theoretically demonstrate how weak fabrication disorder due to surface roughness dramatically reduces the band-edge performance of coupled-cavity waveguides in semiconductor photonic crystal slabs. We find that surface roughness largely affects the band-edge performance through the introduction of random variations in the individual cavity frequencies, Omega(0), rather than through variations in the tight-binding coupling coefficients, kappa. Using model roughness parameters comparable to state-of-the-art structures, the standard deviation of Omega(0) is estimated to be sigma(omega 0)greater than or similar to 1x10(-4) Omega(0). High-index-contrast fabrication imperfections are found to broaden the photon density of states at the band edge with a characteristic linewidth of gamma(e)approximate to sigma(4/3)(omega 0)/(2 Omega(0)kappa)(1/3). This implies a minimal band-edge group velocity of around v(g)similar to c/120, consistent with experiments. For applications toward modified spontaneous emission, we show that the characteristic linewidth gamma(e) is, unfortunately, a factor of 5 greater than the largest band-edge coupling rate for which strong photon quantum dot band-edge interactions can occur. Although large Purcell factors can still be achieved in the presence of disorder, an embedded semiconductor quantum dot then couples to a lossy (disorder-induced) propagation mode, which may limit the potential applications in coherent quantum optics.