We present a 2D photonic crystal system for interacting with cold cesium (Cs) atoms. The band structures of the 2D photonic crystals are predicted to produce unconventional atom-light interaction behaviors, including anisotropic emission, suppressed spontaneous decay, and photon-mediated atom-atom interactions controlled by the position of the atomic array relative to the photonic crystal. An optical conveyor technique is presented for continuously loading atoms into the desired trapping positions with optimal coupling to the photonic crystal. The device configuration also enables application of optical tweezers for controlled placement of atoms. Devices can be fabricated reliably from a 200-nm silicon nitride device layer using a lithography-based process, producing predicted optical properties in transmission and reflection measurements. These 2D photonic crystal devices can be readily deployed to experiments for many-body physics with neutral atoms and engineering of exotic quantum matter.
We present a 2D photonic crystal system for interacting with cold cesium (Cs) atoms. The band structures of the 2D photonic crystals are predicted to produce unconventional atom-light interaction behaviors, including anisotropic emission, suppressed spontaneous decay, and photon-mediated atom-atom interactions controlled by the position of the atomic array relative to the photonic crystal. An optical conveyor technique is presented for continuously loading atoms into the desired trapping positions with optimal coupling to the photonic crystal. The device configuration also enables application of optical tweezers for controlled placement of atoms. Devices can be fabricated reliably from a 200-nm silicon nitride device layer using a lithography-based process, producing predicted optical properties in transmission and reflection measurements. These 2D photonic crystal devices can be readily deployed to experiments for many-body physics with neutral atoms and engineering of exotic quantum matter.
Development of technology can allow access to new regimes in science and creation of new fields of research. The development of ultra-high finesse mirror technology enabled the development of the field of cavity quantum electrodynamics, and an abundance of wonderful physics experiments soon followed. The sophistication of the field of nano-fabrication and nano-photonics would allow unprecedented capability to mold the shape and flow of light, and provide a novel platform for efficient and hopefully integrable quantum systems. In this project, we hope to interface cold atoms, perhaps the most quintessential of quantum systems, to the engineering power of nano-photonics. We believe this field of study will not only lead to the demonstration of new physics in the quantum regime, but work toward building a network with quantum capabilities mediated by optical channels. In this project, we develop a nano-fabricated platform capable of interfacing nano-photonic devices with cold Cesium atoms in free-space. Nano-photonic waveguide devices are fabricated in a Silicon Nitride device layer on Silicon substrate. The fabrication is compatible with conventional semiconductor fabrication processes, and the chip design has been adapted to allow incorporation with free-space optics to support cold Cesium atom cloud around the waveguides. An ultra-high vacuum system that is compatible to the chip and its supporting structures was constructed to perform experiments. With our system, we were able to fabricate and characterize nano-photonic structures, including 1D photonic crystal waveguides, cavities, and 2D photonic crystal slabs. For the 1D photonic crystal waveguide devices, enhanced atom-light coupling between localized Cesium atoms in the vicinity of the devices, and also atom-atom interaction between Cesium atoms mediated by the guided mode of the photonic crystal waveguide, has been observed. The 2D photonic devices allow us many capabilities beyond that of the 1D waveguide. Demonstration of exotic optical properties including natural decay rate suppression and circular polarization engineering, should be within reach in the near future.
Abstract Integrating nanophotonics and cold atoms has drawn increasing interest in recent years due to diverse applications in quantum information science and the exploration of quantum many‐body physics. For example, dispersion‐engineered photonic crystal waveguides (PCWs) permit not only stable trapping and probing of ultracold neutral atoms via interactions with guided‐mode light, but also the possibility to explore the physics of strong, photon‐mediated interactions between atoms, as well as atom‐mediated interactions between photons. While diverse theoretical opportunities involving atoms and photons in 1D and 2D nanophotonic lattices have been analyzed, a grand challenge remains the experimental integration of PCWs with ultracold atoms. Here, an advanced apparatus that overcomes several significant barriers to current experimental progress is described, with the goal of achieving strong quantum interactions of light and matter by way of single‐atom tweezer arrays strongly coupled to photons in 1D and 2D PCWs. Principal technical advances relate to efficient free‐space coupling of light to and from guided modes of PCWs, silicate bonding of silicon chips within small glass vacuum cells, and deterministic, mechanical delivery of single‐atom tweezer arrays to the near fields of photonic crystal waveguides.
Strongly interacting systems of atoms and photons are an important resource in many active areas of research, including quantum information science, quantum simulation, and metrology. Frequently, the strength of these interactions is enhanced by using an optical resonator to confine light to a small volume. In recent years, there have been efforts to replace traditional Fabry–Pérot resonators, formed from macroscopic mirrors, with micro- and nano-fabricated systems, leveraging techniques and infrastructure from semiconductor manufacture to scalably produce high-quality, small mode volume waveguides and resonators. Of particular interest are nano-fabricated photonic crystals, in which very fine control over modal and dispersion properties is possible. Here I describe our efforts to reliably produce photonic crystal waveguides with guided modes designed to trap and interrogate an array of ultracold cesium atoms. Specifically, I present models capturing band placement, modal structure, finite photonic crystal effects, and waveguide input and output coupling; I discuss the techniques we use to fabricate our photonic crystal waveguides; and I describe our characterization capabilities and the packaging and installation of the waveguides into the atomic physics system.
Integrating ultracold atoms with nanophotonics enables the exploration of new paradigms in quantum optics and many body physics. Advanced fabrication capabilities for low-loss dielectric materials provide powerful tools to engineer light-matter coupling of photons and atoms. For example, dispersion-engineered photonic crystal waveguides (PCWs) permit not only stable trapping and probing of atoms via interactions with guided mode (GM) light, but also the possibility to study the physics of strong photon-mediated interactions between atoms. This thesis describes the design of a quasi-one-dimensional structure, the alligator photonic crystal waveguide (APCW), which has already allowed for the observation of some of those features. Furthermore, external illumination schemes allow for the trapping and transport of atoms near the dielectric device. Here, atoms loaded into a one-dimensional optical lattice are transported through the APCW. As the atoms trapped in the lattice approach the APCW, the combination of lattice and GM potential can smoothly guide atoms into the gap between the two dielectric nanobeams. Therefore, the transmission of a weak guided mode probe is modulated at the rate determined by the lattice moving through the APCW. In the near future, single atoms can then be transferred from the moving lattice into optical traps formed in each unit cell by GMs of the APCW. Moreover, a characterization of a simple 2D photonic crystal slabs design is presented.
Trapped atoms near nanophotonics form an exciting platform for bottom-up synthesis of strongly interacting quantum matter. The ability to induce tunable long-range atom-atom interactions with photons presents an opportunity to explore many-body physics and quantum optics. Here we implement a configurable optical tweezer array over a planar photonic circuit tailored for cold atom integration and control for trapping and high-fidelity imaging of one or more atoms in an array directly on a photonic structure. Using an optical conveyor belt formed by a moving optical lattice within a tweezer potential, we show that single atoms can be transported from a reservoir into close proximity of a photonic interface, potentially allowing for the synthesis of a defect-free atom-nanophotonic hybrid lattice. Our experimental platform can be integrated with generic planar photonic waveguides and resonators, promising a pathway towards on-chip many-body quantum optics and applications in quantum technology.
Abstract Trapped atoms near nanophotonics form an exciting platform for bottom-up synthesis of strongly interacting quantum matter. The ability to induce tunable long-range atom-atom interactions with photons presents an opportunity to explore many-body physics and quantum optics. Here we implement a configurable optical tweezer array over a planar photonic circuit tailored for cold atom integration and control for trapping and high-fidelity imaging of one or more atoms in an array directly on a photonic structure. Using an optical conveyor belt formed by a moving optical lattice within a tweezer potential, we show that single atoms can be transported from a reservoir into close proximity of a photonic interface, potentially allowing for the synthesis of a defect-free atom-nanophotonic hybrid lattice. Our experimental platform can be integrated with generic planar photonic waveguides and resonators, promising a pathway towards on-chip many-body quantum optics and applications in quantum technology.