ACOUSTO-OPTICAL PHASED ARRAYS (A-OPA)

为虚拟/增强/混合现实（VR/AR/MR）、三维全息显示和固态光探测与测距（LiDAR）系统开发低功耗、高效的光学接口是一个公认的挑战。如果能够克服，最终将对我们的社会产生变革性影响的新应用将成为可能。这些光学接口的核心是光学相控阵（OPA），这是一种基于半导体的设备，可以通过可调组件控制光的相位来引导光束。迄今为止所证明的OPA要么依赖于液晶，要么依赖于热调谐的集成光子平台。虽然结构紧凑，但这些opa消耗瓦特的功率。降低OPA的功耗是本项目的最终目标。通过材料、器件设计和组件集成方面的创新，该项目将研究新型OPA（声光相控阵）开发背后的基础科学和工程挑战。如果成功，该项目将为开发新型opa奠定基础，这将有助于为VR/AR/MR、自动驾驶汽车或远程传感器通信部署高效的光学接口。A-OPA的影响将是破坏性的，并改变我们与人类和机器的互动。更广泛地说，材料、器件和技术方面的基础研究将通过在光网络、自由空间通信、光交换和互连方面实现一系列新的应用，从而影响整个光子界。所提出的a - opa将铌酸锂（LN）薄膜与三硫化砷（As2S3）薄膜集成在一起，铌酸锂（LN）是一种光学损耗低、电光系数最高、机电系数非常大的材料，而三硫化砷（As2S3）是一种光学损耗相对低、声光系数最高的硫系材料之一。利用LN中的电光效应和As2S3中的声光效应，使光沿两个正交角度定向。先进的微加工工艺的发展允许这些材料集成在非常有限的几何形状中，因此光在亚微米波导中以低损耗引导，高效率的电声换能器建立在同一芯片上。非常低的电压和功率将用于通过LN中的电光效应将光的相位转向一个方向。绝缘体堆上的LN将被设计成有效地将声波驱动到未释放的As2S3薄膜中。通过在As2S3中激发高频声波，可以在芯片表面雕刻出可变间距的光栅，从而使光偏离平面。最终的技术目标是设计一种高性能的OPA，与最先进的OPA相比，功耗显著降低。该奖项反映了美国国家科学基金会的法定使命，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。

The development of low power and efficient optical interfaces for virtual/augmented/mixed reality (VR/AR/MR), three dimensional holographic displays and solid-state light detection and ranging (LiDAR) systems is a recognized challenge. If overcome, new applications that will ultimately have a transformative impact on our society would be enabled. At the heart of these optical interfaces there is the optical phased array (OPA), a semiconductor-based device that can steer a light beam by controlling the phase of light through tunable components. The OPA demonstrated to date rely either on liquid crystals or integrated photonic platforms with thermal tuning. While compact, these OPAs consume Watts of power. Reducing power consumption of the OPA is the ultimate goal of this project. Through innovations in materials, device design and component integration, this project will investigate the fundamental scientific and engineering challenges behind the development of a new class of OPA, which is dubbed the acousto-optic phased array (A-OPA). If successful, this project will lay the foundations for the development of a new class of OPAs that would facilitate the deployment of efficient optical interfaces for VR/AR/MR, self-driving cars or remote sensor communication. The impact of the A-OPA would be disruptive and transform our interactions with humans and machines. More broadly, the fundamental investigations in materials, devices and technology will impact the photonic community at large by enabling a new host of applications in optical networking, free-space communication, optical switching and interconnects.The proposed A-OPA integrates thin films of lithium niobate (LN), a material with low optical losses, the highest electro-optic coefficient and very large electromechanical coefficient, with arsenic trisulfide (As2S3), a chalcogenide material with relatively low optical losses and one of the highest acousto-optic coefficients. Light is steered along two orthogonal angles by means of the electro-optic effect in LN and the acousto-optic effect in As2S3. The development of advanced micromachining processes permits the integration of these materials in very confined geometries so that light is guided with low loss in sub-micron waveguides and high efficiency electro-acoustic transducers are built on the same chip. Very low voltages and power will be used to steer the phase of light in one direction through the electro-optic effect in LN. The LN on insulator stack will be engineered to efficiently drive acoustic waves into unreleased films of As2S3. By exciting high frequency acoustic waves in As2S3, gratings of variable pitch will be sculpted on the surface of the chip and steer light out of plane. The ultimate technical goal is to devise a high performance OPA with significantly reduced power consumption with respect to the state-of-the-art.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.