de Gaay Fortman Nelson, Pal Debapriya, Schall Peter, Koenderink A Femius
Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
Department of Physics of Information in Matter and Center for Nanophotonics, NWO-I Institute AMOLF, Science Park 104, NL1098XG Amsterdam, The Netherlands.
ACS Photonics. 2025 Jan 7;12(2):1163-1173. doi: 10.1021/acsphotonics.4c02323. eCollection 2025 Feb 19.
Dense plasmon lattices are promising as experimentally accessible implementations of seminal tight-binding Hamiltonians, but the plasmonic dispersion of interest lies far beyond the light line and is thereby inaccessible in far-field optical experiments. In this work, we make the guided mode dispersion of dense hexagonal plasmon antenna lattices visible by bandfolding induced by perturbative scatterer size modulations that introduce supercell periodicity. We present fluorescence enhancement experiments and reciprocity-based T-matrix simulations for a systematic variation of perturbation strength. We evidence that folding the -point into the light cone gives rise to a narrow plasmon mode, achieving among the highest reported quality factors for plasmon lattice resonances in the visible wavelength range despite a doubled areal density of plasmon antennas. We finally show -point lasing and spontaneous symmetry breaking between the bandfolded - and '-modes, signifying that intrinsic symmetry properties of the dense plasmon lattice are maintained and can be observed upon band folding.
密集等离子体晶格有望成为开创性紧束缚哈密顿量的可实验实现方式，但感兴趣的等离子体色散远超出光线，因此在远场光学实验中无法获取。在这项工作中，我们通过引入超胞周期性的微扰散射体尺寸调制所诱导的能带折叠，使密集六边形等离子体天线晶格的导模色散变得可见。我们针对微扰强度的系统变化进行了荧光增强实验和基于互易性的T矩阵模拟。我们证明，将Γ点折叠到光锥中会产生一个窄等离子体模式，尽管等离子体天线的面密度增加了一倍，但在可见波长范围内实现了等离子体晶格共振所报道的最高品质因数之一。我们最终展示了Γ点激光以及能带折叠的Γ模和Γ'模之间的自发对称性破缺，这表明密集等离子体晶格的固有对称特性得以保持，并且在能带折叠时可以被观察到。
