Nonlinear Goniometry by Second-Harmonic Generation in AlGaAs Nanoantennas
Nonlinear Goniometry by Second-Harmonic Generation in AlGaAs Nanoantennas
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DOI：
10.1021/acsphotonics.8b00810
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发表时间：
2018-11-01
期刊：
影响因子：
7
通讯作者：
Neshev, Dragomir N.
中科院分区：
文献类型：
--
作者：
Carletti, Luca;Marino, Giuseppe;Neshev, Dragomir N.
高介电常数的半导体纳米谐振器已显示出巨大的潜力，增强非线性光物质的相互作用，在纳米尺度上，由于丰富的各种谐振与低的光学损耗和强大的体非线性相结合的可用性。AlGaAs纳米天线中的二次谐波产生可以是非常有效的，并且表现出复杂的辐射图案。然而，这种远场轮廓的复杂性对实际应用和检测效率施加了严重的限制。在这项工作中，我们证明，无论是实验和数值，控制的角度分布的二次谐波辐射图案从单片AlGaAs上AlOx纳米盘通过改变偏振和泵浦光束的入射角。通过将具有s偏振光的光束的入射角从0度调谐到45度，由于非线性辐射图案对泵浦光束性质的强烈依赖性，检测到的二次谐波信号单调增加到超过一个数量级。我们的研究结果表明，可以进行精确的角度测量的泵倾斜与二次谐波信号的相对强度变化高达0.25度（-1）和偏振歧视，从而建立了一个新的技术，无背景的纳米非线性角度测量。
High-permittivity semiconductor nanoresonators have shown great potential for enhanced nonlinear light matter interactions at the nanoscale due to the availability of a rich variety of resonances combined with low optical losses and a strong bulk nonlinearity. Second-harmonic generation in AlGaAs nanoantennas can be extremely efficient and exhibits a complex radiation pattern. However, the complexity of this far-field profile imposes severe constraints on practical applications and detection efficiency. In this work, we demonstrate, both experimentally and numerically, the control over the angular distribution of the second-harmonic radiation pattern from a monolithic AlGaAs-on-AlOx nanodisk by varying the polarization and the angle of incidence of the pump beam. By tuning the angle of incidence of a beam with s-polarized light from 0 to 45 degrees, the detected second-harmonic signal is monotonically increased up to over an order of magnitude due to the strong dependence of the nonlinear radiation pattern on the pump beam properties. Our results demonstrate that precise angular measurements of the pump inclination can be performed with a relative intensity change of the second-harmonic signal up to 0.25 deg(-1) and polarization discrimination, therefore establishing a new technique for background-free nanoscale nonlinear goniometry.