ACOUSTO-OPTICAL PHASED ARRAYS (A-OPA)

为虚拟/增强/混合现实(VR/AR/MR)、三维全息显示器和固态光探测和测距(LiDAR)系统开发低功率和高效的光学接口是一个公认的挑战。如果被攻克，最终将对我们的社会产生变革性影响的新应用程序将成为可能。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，可以通过控制通过可调元件的光的相位来控制光束。到目前为止，OPA要么依赖于液晶，要么依赖于带有热调的集成光子平台。虽然结构紧凑，但这些Opa消耗的功率为瓦特。降低OPA的功耗是本项目的最终目标。通过在材料、器件设计和组件集成方面的创新，该项目将调查开发一种新的OPA背后的基本科学和工程挑战，这类OPA被称为声光相控阵(A-OPA)。如果成功，该项目将为开发新类别的OPA奠定基础，该OPA将促进为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的影响将是颠覆性的，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来影响整个光子界。建议的A-OPA将具有低光学损耗、最高电光系数和非常大的机电系数的Nb酸锂(LN)薄膜与三硫化砷(As2S3)相结合，As2S3是一种光学损耗相对较低的硫化物材料，也是声光系数最高的材料之一。利用LN中的电光效应和As2S3中的声光效应，光被引导成两个直角。先进微加工工艺的发展使得这些材料可以在非常有限的几何形状中集成，从而在亚微米波导中以低损耗引导光，并在同一芯片上构建高效率的电声换能器。极低的电压和功率将被用来通过LN的电光效应在一个方向上控制光的相位。绝缘体上的LN将被设计成有效地将声波驱动到未发布的As2S3薄膜中。通过在As2S3中激发高频声波，在芯片表面雕刻出变螺距的光栅，引导光出平面。最终的技术目标是设计一种高性能的OPA，与最先进的技术相比，大大降低了功耗。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.