PFI:AIR - TT: Demonstration of parametrically robust wideband resonant reflectors

该PFI：AIR技术翻译项目的重点是翻译与新型宽带反射器相关的研究发现，以满足激光制造和红外成像系统等各种应用对新型光子元件的需求。这一创新非常重要，因为新的基本物理效应将被应用于实现当前竞争技术无法实现的解决方案。该项目将产生新的设计和原型反射器，这些反射器将在重要频段进行详细测试。所提出的反射器将具有以下独特的功能：高度的参数稳定性，大的光谱带宽，紧凑的尺寸，和高产量的制造。这些特征提供了包括高效率、低损耗、制造经济性和应用鲁棒性的优点。这些单层器件可以在基底上或作为膜制造。它们避免了商业薄膜多层反射器中的多个界面和相关问题;因此，热膨胀效应和粘附问题被最小化。这些反射器可以应用在光谱区域中的薄膜多层膜的沉积是不切实际的或不可能的。因此，这一创新提供了新的解决方案，并可能在相当大的市场空间中有效竞争。 该项目解决了以下技术差距，因为它从研究发现转化为商业应用：（1）在这种情况下，所提出的基本谐振效应的效用的验证，以及（2）验证具有高效宽带光谱的实际原型反射器可以制造。所提出的谐振反射器设计有光栅，其中光栅脊与相同的材料匹配，从而避免局部反射和相位变化。由于这种临界界面具有零折射率对比度，我们称之为“零对比度光栅”。“对于具有两部分周期的简单光栅，我们使用数值计算来证明零对比度光栅提供了极大的平顶带宽和参数稳定的光谱;该项目旨在通过实验来演示这些设备。总之，主要目标是制造在~1.2- 12微米光谱区工作的反射器原型;验证反射率超过99%的~600-1100 nm带宽;验证预测的参数稳定性;演示偏振和非偏振反射器;并验证理论预测的~10- 100 nm带宽的99.99%反射率。这些器件是使用强大的电磁优化算法设计的，并且它们是使用标准的纳米制造方法制造的，包括薄膜沉积、光刻图案化和蚀刻。它们的特征在于在~1至12微米波段的光谱分析。因此，该项目提供了紧凑，坚固，偏振和非偏振的谐振反射器，可在广泛的光谱应用空间内工作，经典方法无法提供有效的解决方案。此外，参与该项目的人员，包括本科生和研究生，将通过注册PI定期教授的“工程创业”获得创业经验，包括商业规划。

This PFI: AIR Technology Translation project focuses on translating research discoveries associated with a new class of wideband reflectors to fill the need for new photonic components in a broad variety of applications including laser manufacturing and infrared imaging systems. This innovation is important as new fundamental physical effects will be applied to enable solutions not attainable with current competing technology. The project will result in new designs and prototype reflectors that will be tested in detail for operation in important frequency bands. The proposed reflectors will have the following unique features: high degree of parametric stability, large spectral bandwidth, compact size, and high-yield manufacturing. These features provide advantages including high efficiency, low loss, economy in fabrication, and robustness in applications. These single-layer devices can be fabricated on substrates or as membranes. They avoid the multiple interfaces and associated issues in commercial thin-film multilayer reflectors; thus, thermal expansion effects and adhesion problems are minimized. These reflectors can be applied in spectral regions for which the deposition of thin-film multilayers is impractical or impossible. Therefore, this innovation provides new solutions and is likely to compete effectively in a sizeable market space. This project addresses the following technology gaps as it translates from research discovery toward commercial application: (1) verification of the utility of the proposed fundamental resonance effect in this context, and (2) verification that practical prototype reflectors with high-efficiency wideband spectra can be fabricated. The proposed resonant reflectors are designed with gratings in which the grating ridges match to an identical material, thereby avoiding local reflections and phase changes. As this critical interface possesses zero refractive-index contrast, we call them "zero-contrast gratings." For simple gratings with two-part periods, we use numerical calculations to show that zero-contrast gratings provide extremely large flattop bandwidths and parametrically stable spectra; this project aims to demonstrate these devices experimentally. In summary, the main goals are to fabricate reflector prototypes operating in the ~1.2- to 12- micron spectral region; verify bandwidths of ~600-1100 nm with reflectance exceeding 99%; verify the predicted parametric stability; demonstrate polarized and unpolarized reflectors; and verify theoretical predictions of 99.99% reflectance for ~10- to 100-nm bandwidths. These devices are designed using powerful electromagnetic optimization algorithms, and they are made using standard nanofabrication methods including thin-film deposition, lithographic patterning, and etching. They are characterized by spectral analysis in the ~1- to 12- micron wavelength band. Hence, the project delivers compact, robust, polarized and unpolarized resonant reflectors that work within a broad spectral application space where classical methods fail to deliver effective solutions. In addition, personnel involved in this project, including undergraduate and graduate students, will receive entrepreneurial experiences, including business planning, by enrolling in "Engineering Entrepreneurship" that is taught by the PI on a regular basis.