Characterizing enhanced nonlinear optical responses in the mid-infrared spectrum

这项提议要求为中红外(2至20微米)光谱范围内的灵敏光学探测器提供资金，以便能够测量各种介电材料的强烈增强的非线性光学响应，以及对薄膜和时变变形表面的相干热发射进行空间、光谱和时间调整。具体地说，需要资金购买光功率探测器和相关电子设备，用于测量巨大的超快非线性光学响应，以及用于检测中红外样品的热指纹和光谱指纹的复杂光谱系统。这种用于中红外的必要检测设备将使申请者和众多HQP将他们在可见光和近红外区域(400-2000 nm)建立的非线性光学专业知识带入到迄今大部分未被探索的中红外光谱，在那里我们预测声子介导的共振固态材料中的光-物质相互作用将显示出巨大的非线性光学增强，并为热发射工程创造机会。*由该设备启动的研究是由我们最近的四个发现推动的：1)由于固有的等离子体共振，材料的非线性光学响应在近零介电常数下得到极大的增强，这是我们在近红外中所展示的；2)预测了声子固态材料在中红外波段的非线性光学性质可以远远超过等离子体材料的非线性光学性质；3)近零介电常数材料可以动态地控制等离子体和介电散射体的共振，我们在近红外中已经证明了这一点；4)理论预测，利用近零介电常数可以增强或抑制黑体的时空相干性和发射率。然而，所有的实验工作都局限于近红外光谱，因为无论是在渥太华大学还是在渥太华核研究中心的设施中，都完全没有可用的测量设备，这些设备与在中红外波段具有强烈光脉冲的飞秒激光系统兼容。*这些专门的中红外光学探测系统对于将申请者的NSERC资助的非线性光学和亚表面研究从近红外光谱扩展到中红外光谱至关重要，因为到目前为止，技术限制阻碍了非线性光学研究。申请者希望揭示声子共振产生的这些明显的非线性比在等离子体共振下观察到的更强，从而为两者提供见解。此外，了解基于这种独特的物理现象的大的非线性响应可以导致新的相干源、吸收体和信号处理设备的发展，这些设备有可能在光伏热发射工程、环境危害和污染物的光学远程检测、主动控制热和光学伪装，甚至可能实现超过黑体极限的热发射工程中得到应用。

This proposal requests funding for sensitive optical detectors in the mid-infrared (2 to 20 um) spectral range, enabling measurements of strongly enhanced nonlinear optical responses of various dielectric materials as well as the spatial, spectral and temporal tailoring of coherent thermal emission from films and time-varying metasurfaces. Specifically, funds are requested to purchase optical power detectors with associated electronics for measurements of giant ultrafast nonlinear optical responses and a sophisticated spectrometry system for detecting the thermal and spectral fingerprints of samples in the mid-IR. This necessary detection equipment for mid-IR will enable the applicants and numerous HQP to bring their nonlinear optics expertise established in the visible and near-IR regimes (400-2000 nm) into the so far largely unexplored mid-IR spectrum, where we predict light-matter interactions in phonon-mediated resonant solid state materials will reveal giant nonlinear optical enhancements, and create opportunities for thermal emission engineering.***Research enabled by this equipment is motivated by four of our recent findings: 1)nonlinear optical response of materials are greatly enhanced at near-zero permittivities due to inherent plasmonic resonances, which we have shown in near-IR; 2)prediction that the nonlinear optical properties of phononic solid state materials in the mid-IR can greatly exceed those of plasmonic ones; 3)near-zero permittivity materials can dynamically control the resonances of plasmonic and dielectric scatterers, which we have shown in near-IR; and 4)the theoretical prediction that the spatiotemporal coherence and emissivity of a blackbody can be enhanced or suppressed using near-zero permittivity. However, all experimental work has been confined to the near-IR spectrum due to the complete lack, either at uOttawa or in the NRC Ottawa facilities, of available measurement devices that are compatible with a femtosecond laser system with intense optical pulses in the mid-IR.***These specialized mid-IR optical detection systems are crucial to the expansion of the applicants' NSERC-funded research on nonlinear optics and metasurfaces from the near-IR to the mid-IR, where technological limitations have thus far prevented nonlinear optics research. The applicants hope to reveal that these distinct nonlinearities stemming from phononic resonances are even stronger than those observed at plasmonic resonances, thus providing insights into both. Furthermore, understanding large nonlinear responses based on this distinct physical phenomena could leading to the development of new coherent sources, absorbers, and signal processing devices with the potential of finding applications in thermal emission engineering of photovoltaics, optical remote detection of environmental hazards and pollutants, active-control thermal and optical camouflage and perhaps even achieving thermal emission engineering that could surpass the blackbody limit.