Hafnia-based platform for high-index visible and UV integrated photonics

基于 Hafnia 的高折射率可见光和紫外集成光子学平台

• 批准号: 2301389
• 负责人: Karan Mehta
• 金额: $ 44.7万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2301389&HistoricalAwards=false
• 关键词: Hafnia; based; platform; index; visible

Integrated photonics at visible and ultraviolet wavelengths stand to enable applications spanning quantum systems based on individual atoms, ions, and defects in solids, bio-chemical spectroscopy, and neural stimulation and probing. Operation at visible and ultraviolet wavelengths requires different material platforms and device architectures as compared to the comparatively mature near infrared, where communications applications have spurred significant development. The lack of wide-bandgap materials platforms transmissive to these high energy photons has been a major limitation on development of integrated photonics at these short wavelengths. This program develops a new CMOS-compatible platform for ultraviolet and visible photonics based on thin-film deposited hafnia, whose relatively high refractive index is a critical advantage over the current alternative for ultraviolet integrated photonics, alumina. This program explores strategies to inhibit crystallization of hafnia, which has been a major obstacle to realization of low optical losses, by controlled incorporation of other elements into films. The resulting composite films maintain the bulk of hafnia's advantage in refractive index, while reducing losses by orders of magnitude. The work further explores and develops materials processing and fabrication techniques to pattern this material into low-loss photonic devices, and develops novel photonic device concepts leveraging the new platform motivated by application in atomic quantum systems. This work will enable significantly higher performance photonics at blue/UV wavelengths, and due to the CMOS compatibility of the proposed platform, enables rapid integration into state-of-the-art manufacturing platforms. Undergraduate education and participation in the research is a key component of the program, as are outreach efforts exposing K-12 students to cutting-edge work happening in optical and atomic science and technology. The program explores routes to optimizing material loss and index in HfO2/Al2O3 composites formed by atomic layer deposition, develops nanofabrication processes for these composites to enable lithographically defined nanophotonics, and pursues detailed characterization of the developed platform. The high refractive index of the composite material as compared to the current best alternative, pure Al2O3, is a significant enabling advantage for multiple photonic components including grating couplers, photonic crystals, microresonators, and active electro- and acousto-optic devices. Furthermore, this work introduces novel device architectures leveraging the platform capability to address key challenges in application to atomic quantum systems. In particular, a novel concept is introduced to enable robust, broadband generation of pure circularly polarized radiation (99.9% purity in relative intensity) from passive integrated photonics. This concept takes advantage of the high refractive index contrast enabled by the developed platform, and will be pursued in theory and demonstrated in experiment. The work also explores novel hybrid schemes for blue/ultraviolet parallel electro-optic control enabled by HfO2’s high index, via integration with bulk beta barium borate. This work opens future directions in efficient integrated short-wavelength nonlinear optics, as well as architectures for integrated acousto-optics in the blue/ultraviolet. The program addresses key challenges in scaling quantum systems, with advances spanning photonic materials/processing, as well as in passive and active optical functionalities. Due to the material's compatibility with CMOS fabrication, this work stands to rapidly impact integrated photonics for atomic quantum systems and at blue/ultraviolet wavelengths more broadly.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

可见光和紫外波长的集成光子学可以实现基于单个原子、离子和固体缺陷的量子系统、生物化学光谱学以及神经刺激和探测的应用。与相对成熟的近红外相比，在可见光和紫外波长下的操作需要不同的材料平台和设备架构，其中通信应用已经刺激了显着的发展。对这些高能量光子透射的宽带隙材料平台的缺乏已经成为在这些短波长下开发集成光子学的主要限制。该计划开发了一种新的CMOS兼容平台，用于基于薄膜沉积氧化铝的紫外和可见光光子学，其相对较高的折射率是目前紫外集成光子学替代品氧化铝的关键优势。该计划探讨了通过控制将其他元素掺入到薄膜中来抑制氧化铌结晶的策略，氧化铌结晶一直是实现低光学损耗的主要障碍。由此产生的复合薄膜保持了大部分的折射率优势，同时减少了几个数量级的损失。这项工作进一步探索和开发了材料加工和制造技术，将这种材料图案化为低损耗光子器件，并开发了新的光子器件概念，利用了原子量子系统中应用的新平台。这项工作将使蓝光/紫外波长的光子学性能显著提高，并且由于所提出的平台的CMOS兼容性，能够快速集成到最先进的制造平台中。本科教育和参与研究是该计划的一个关键组成部分，因为是外展工作，使K-12学生接触到光学和原子科学与技术领域的前沿工作。该计划探索了优化原子层沉积形成的HfO 2/Al 2 O3复合材料的材料损耗和折射率的途径，为这些复合材料开发了纳米纤维工艺，以实现光刻定义的纳米光子学，并对开发的平台进行了详细的表征。与当前最佳替代品纯Al 2 O3相比，复合材料的高折射率对于包括光栅耦合器、光子晶体、微谐振器以及有源电光器件和声光器件在内的多个光子器件是显著的有利优势。此外，这项工作引入了新的设备架构，利用平台能力来解决应用于原子量子系统的关键挑战。特别是，引入了一种新的概念，使鲁棒的，宽带产生的纯圆偏振辐射（99.9%纯度的相对强度）从被动集成光子。这个概念利用了所开发的平台所实现的高折射率对比度，并将在理论上进行研究并在实验中进行验证。这项工作还探讨了新的混合方案，蓝色/紫外线并行电光控制启用HfO 2的高指数，通过集成与散装β硼酸钡。这项工作开辟了未来的方向，在有效的集成短波长非线性光学，以及架构集成声光在蓝色/紫外线。该计划解决了缩放量子系统的关键挑战，其进步跨越光子材料/处理以及无源和有源光学功能。由于该材料与CMOS制造的兼容性，这项工作将迅速影响原子量子系统和更广泛的蓝色/紫外波长的集成光子学。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。