Cavity-enhanced second-harmonic generation via nonlinear-overlap optimization
Cavity-enhanced second-harmonic generation via nonlinear-overlap optimization
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DOI：
10.1364/optica.3.000233
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发表时间：
2016-03-20
期刊：
影响因子：
10.4
通讯作者：
Rodriguez, Alejandro W.
中科院分区：
文献类型：
--
作者：
Lin, Zin;Liang, Xiangdong;Rodriguez, Alejandro W.
我们描述了一种新的方法，拓扑优化的基础上，实现高效率的二次谐波产生（SHG）的波长尺度的光子结构的自动发现。一个关键的区别，从以前的配方和设计，寻求最大限度地提高珀塞尔因素在个别频率是，我们的方法不仅旨在实现频率匹配（整个倍频程）和大的辐射寿命，但也优化了同样重要的非线性耦合品质因数（β）超过酒吧，涉及一个复杂的空间模式之间的积分。我们将这种方法应用于优化微柱和光栅板腔的特定问题（一维多层结构），并证明了各种材料平台可以支持具有必要频率的模式，大寿命Q > 10（4），小模态体积类似于（λ/n）（3），并且在条10（-2）上极大（β），导致与现有技术的光子设计相比SHG效率的数量级增强。这种巨大的（β）过棒减轻了对超窄线宽的需求，从而为具有更快操作时间尺度和对制造缺陷的更高容限的波长级SHG器件铺平了道路。(C)2016美国光学学会
We describe a novel approach based on topology optimization that enables automatic discovery of wavelength-scale photonic structures for achieving high-efficiency second-harmonic generation (SHG). A key distinction from previous formulation and designs that seek to maximize Purcell factors at individual frequencies is that our method aims to not only achieve frequency matching (across an entire octave) and large radiative lifetimes, but also optimizes the equally important nonlinear-coupling figure of merit (beta) over bar, involving a complicated spatial overlap-integral between modes. We apply this method to the particular problem of optimizing micropost and grating-slab cavities (one-dimensional multilayered structures) and demonstrate that a variety of material platforms can support modes with the requisite frequencies, large lifetimes Q > 10(4), small modal volumes similar to(lambda/n)(3), and extremely large (beta) over bar 10(-2), leading to orders of magnitude enhancements in SHG efficiency compared to state-of-the-art photonic designs. Such giant (beta) over bar alleviate the need for ultranarrow linewidths and thus pave the way for wavelength-scale SHG devices with faster operating timescales and higher tolerance to fabrication imperfections. (C) 2016 Optical Society of America