Izadshenas Jahromi Saeid, Słowik Karolina
Opt Lett. 2024 Jul 15;49(14):3914-3917. doi: 10.1364/OL.531669.
We present a hybrid graphene-gold nanoantenna designed to enhance multiphoton absorption signals in molecules. The enhancement process involves two key steps: Firstly, the graphene component of the antenna supports molecular absorption in the mid-infrared and terahertz bands. By applying gate voltage, one can adjust the spectral positions of its resonances and select the desired absorption order, determining the number of photons absorbed in a single transition event. Secondly, gold nanorods with carefully tailored geometrical parameters enhance fluorescent single-photon emission. As a proof of concept, we adjust the geometry parameters of the hybrid antenna to the ATTO 700 dye molecule, taking into account its spectrally resolved emission characteristics. We predict a significant local enhancement of the fluorescence signal indicating the highly nonlinear process of N-photon absorption to exceed 5 orders of magnitude for N = 2 and 13 orders of magnitude for higher nonlinearity orders. Our proposed nanoantenna offers a promising platform for the tunable enhancement of highly nonlinear light-matter interactions.
我们展示了一种混合石墨烯-金纳米天线，其设计目的是增强分子中的多光子吸收信号。增强过程涉及两个关键步骤：首先，天线的石墨烯组件支持分子在中红外和太赫兹波段的吸收。通过施加栅极电压，可以调整其共振的光谱位置并选择所需的吸收阶数，从而确定单个跃迁事件中吸收的光子数。其次，具有精心调整几何参数的金纳米棒增强荧光单光子发射。作为概念验证，我们根据ATTO 700染料分子的光谱分辨发射特性，将混合天线的几何参数进行了调整。我们预测荧光信号会有显著的局部增强，这表明N光子吸收的高度非线性过程对于N = 2时超过5个数量级，对于更高的非线性阶数则超过13个数量级。我们提出的纳米天线为可调谐增强高度非线性光-物质相互作用提供了一个有前景的平台。
