Cavity-Electro-Optomechanical Circuits with Broken Time-Reversal Symmetry

光通常在双向街道上传播——如果它经过反射，向前传播的光就会伴随着向后传播的光。为了消除反向传播的“表亲”，需要光的时间反转对称性破缺。这是一个挑战，因为光子——光的量子——不携带电荷，因此不与磁场相互作用，而磁场是带电粒子（如电子）的时间反转对称性破缺背后的力量。无反射光传播对于光信息通信非常重要，特别是对于稳定激光频率和减轻信号衰减。在小型化的环境中，今天的集成光子微芯片使用低功耗和宽带光学元件来执行传统电子产品无法实现的信息处理和通信。就像光网络一样，光子微芯片的正常工作也得益于反射消除装置。这些器件的芯片级实现，即所谓的光隔离器，仍然是一个突出的挑战。已知光的时间反转对称性可以通过诱导介质折射率的时间调制来打破。一种有效的时间调制方法是在光介质中激发声波，使局部电极化密度发生扰动。在此背景下，本项目将探索由光与机械运动相互作用引起的时间反转对称性破缺，并研究在微芯片上实现的人工光机械结构中的非互反光传播及其相关的新物理。这项工作潜在的更广泛的影响主要在于开发集成光子技术的新设备和方法，通过实践研究和新课程对这一重要领域的学生进行教育，以及通过新一代光电产品提高社会效益。该计划旨在开发一种创新的集成光子电路家族，该电路具有破时反转对称性，由耦合电光机械谐振器中的辐射压力力实现。空腔光力学系统，涉及光强度与机械运动在波长尺度上通过辐射压力的耦合，为明确的时间反转对称性破缺创造了必要的大光学非线性。使用相位相关参量光泵来控制单个腔，突出了可编程合成场的方法，这导致了光和声的非互易性，甚至可能揭示大尺度光机械结构中的拓扑波干涉。压电驱动稳态机械运动，在多模光机械腔中诱导光子跃迁，作为打破时间反转对称性的另一种手段，可以用来提高腔-电-光机械电路的带宽超过机械阻尼率。最突出的工作将是研究电光机械电路中的非互易光子-声子相互作用，并实现重要的光子器件应用，包括非磁性环行器和鲁棒延迟线。在由机械运动驱动的光机械晶体中，新的物理轴承拓扑性质也将被研究。该提案的智力价值主要在于纳米光子网络架构的新范式的发展，这将开启新的研究领域，从光学NEMS到拓扑光力学，并使微波光子学，通信和量子信息的变革技术成为可能。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。

Light generally travels in two-way streets - a forward propagating light is accompanied by a backward propagating light if it undergoes reflection. To eliminate the backward propagating cousin requires time-reversal symmetry breaking of light. This is challenging because photons - the quanta of light- do not carry charge and thus do not interact with magnetic fields which are the force behind time-reversal symmetry breaking of charged particles, such as electrons. Reflection-free light propagation is important to optical information communications, in particular for stabilizing laser frequencies and mitigating signal decay. In a miniaturized setting, today's integrated photonic microchips use low-power and broadband optical elements to perform information processing and communication unavailable with conventional electronic counterparts. Just like an optical network, the proper functioning of the photonic microchips also benefits from reflection-eliminating devices. The chip-scale realization of these devices, so called optical isolators, remains an outstanding challenge. It is known that time-reversal symmetry of light can be broken by inducing time-modulation of media's refractive index. An effective means of such time-modulation can be achieved by exciting acoustic waves in the optical media which perturb local electric polarization density. In this context, this program will explore time-reversal symmetry breaking induced by the interaction between light and mechanical motion, and study non-reciprocal light propagation and associated new physics in artificial optomechanical structures realized on microchips. The potential broader impact of this work lies primarily in the development of new devices and methodologies for integrated photonic technologies, in the education of students in this important field through hands-on research and new courses, and in the improvement of societal benefits with new generations of optoelectronic products.The proposed program aims at developing an innovative family of integrated photonic circuits with broken time-reversal symmetry, enabled by radiation pressure force in coupled electro-optomechanical resonators. Cavity-optomechanical systems, involving the coupling of light intensity to mechanical motion via radiation pressure at wavelength scale, create the requisite large optical nonlinearities for explicitly time-reversal symmetry breaking. The use of phase-correlated parametric optical pumps for controlling individual cavities highlights the approach of programmable synthetic fields, which leads to optical and acoustic nonreciprocity, and may even reveal topological wave interference in large-scale optomechanical structures. Piezoelectric driving of steady state mechanical motion, for inducing photonic transition in multimode optomechanical cavities as another means to break time-reversal symmetry, can be used to boost the bandwidth of cavity-electro-optomechanical circuits beyond the mechanical damping rate. Most prominent of this work will be studying nonreciprocal photon-phonon interactions in electro-optomechanical circuits, and realizing important photonic device applications including non-magnetic circulators and robust delay lines. New physics bearing topological properties in optomechanical crystals driven by mechanical motion will also be investigated. The intellectual merit of this proposal lies primarily in the development of a new paradigm of nanophotonic network architecture that will unlock new lines of research, from optical NEMS to topological optomechanics, and enable transformative technologies for microwave photonics, communications, and quantum information.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.