TY - JOUR
T1 - Cavity-enhanced second-harmonic generation via nonlinear-overlap optimization
AU - Lin, Zin
AU - Liang, Xiangdong
AU - Lončar, Marko
AU - Johnson, Steven G.
AU - Rodriguez, Alejandro W.
N1 - Publisher Copyright:
© 2016 Optical Society of America.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - 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 β, 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 > 104, small modal volumes λ∕n)3, and extremely large β ≳ 10−2, leading to orders of magnitude enhancements in SHG efficiency compared to state-of-the-art photonic designs. Such giant β 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.
AB - 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 β, 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 > 104, small modal volumes λ∕n)3, and extremely large β ≳ 10−2, leading to orders of magnitude enhancements in SHG efficiency compared to state-of-the-art photonic designs. Such giant β 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.
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U2 - 10.1364/OPTICA.3.000233
DO - 10.1364/OPTICA.3.000233
M3 - Article
AN - SCOPUS:84962596249
VL - 3
SP - 233
EP - 238
JO - Optica
JF - Optica
SN - 2334-2536
IS - 3
M1 - 030233
ER -