Zhaowei Liu - US grants

Objective: The objective of this program is to develop a new concept of a high throughput optical microscopy technique with unprecedented imaging resolution as well as speed. By combining two emerging fields, surface plasmon interference engineering with the structured illumination microscopy technique, the proposed plasmonic structured illumination microscopy (PSIM) takes advantage of the superior properties of surface plasmons to significantly improve the spatial resolution. A prototype plasmonic structured illumination microscope will be constructed with 3-5 fold spatial resolution improvement compared with a conventional light microscope. The target imaging speed is 50 frames/second and beyond.
Intellectual Merit: The PSIM is a novel concept and it is the first ever to utilize surface plasmon interference patterns in structured illumination microscopy to improve the imaging resolution. Considering both the high resolution and the high speed, the proposed PSIM will represent a new standard of optical imaging tools that is difficult to realize through any other current techniques.
Broader Impacts: The remarkable performance improvement provided by this proposed PSIM will make profound influences in a broad spectrum of fields wherever a high speed high-resolution optical microscopy is needed. The impact of this research will be far-reaching. The outreach activities include the involvement of graduate and undergraduate students in the project as well as the development of new courses which will be integrated with current under/graduate curricula. More importantly, the PSIM will also be introduced to local biologists through NCMIR, a national public imaging facility, to assist in the new discoveries in their fields.

Diabetes, heart failure, and hepatic failure are diseases of enormous burden to Americans. The effective therapies for these often lethal diseases require the application of novel engineering concepts and technologies. Tissue engineering holds great promise for the treatment of these diseases. Using biodegradable scaffolds, cells are organized in close proximity to each other with a well-defined 3-dimensional (3D) space for the formation of new tissues. While a typical biological cell has a size of several microns, the interactions of cells with the environment occur at a nanoscale. Fabricating such scaffolds with micro- and nano-scale features has been a significant bottleneck for industrial scale production of tissues. The goal of this research is to develop a novel nanomanufacturing system, Hyperlens-Assisted Projection Stereolithography (HAPS), with a sub-50 nm resolution for the direct-write of 3D, heterogeneous biological scaffolds. The research tasks include: a) design and fabrication of the hyperlens by combining simulation with experiments, b) integration of the hyperlens with the projection stereolithography system, c) design and fabrication of complex tissue scaffolds, and d) studying the growth and phenotypical modulation of vascular endothelial cells and smooth muscle cells using the scaffolds.

If successful, this project will help to enhance the emerging US biomanufacturing industry for the production of vascular tissues, skins, bones, and other tissues and organs. The proposed HAPS technique will foster a giant step for scalable, continuous 3D nanomanufacturing of not only functional biomedical devices, but also 3D nanoelectronics, nanophotonics, and nanoenergy devices. Moreover, the results of this work will provide inspiring teaching materials and interesting laboratory projects. The proposed efforts of integrating research with education will offer undergraduates and graduate students increased exposure to nanomanufacturing. The proposed symposia and workshop will greatly enhance the impact of nanomanufacturing research.

Nontechnical description: Photonic metamaterials are artificial constructs whose optical characteristics may be engineered by altering their geometrical structure, as well as their chemical composition. In this project, the research team explores new phenomena that arise when structural features of the metamaterials are of only several nanometers in size. On such a small scale, traditional optical properties such as color and sheen are no longer discernible. Instead, the properties of the materials may now be precisely tuned by carefully varying their nanoscale structure. The overarching goal of this project is to conduct basic science and engineering research on such precision-structured metamaterials, and elucidate their potential applications. This study particularly addresses fundamental aspects of electronic and optical characteristics of nanoscale metamaterials. In addition, undergraduate and graduate students receive hands-on training in the fields of nanoscience and nanotechnology, materials synthesis, characterization, and device design. Achieving a fundamental understanding of artificial optical materials and their fabrication is anticipated to have broad ranging impact on assessing their potential in new optical devices.

Technical description: This project addresses the prospects for achieving fundamental understanding of a new class of hyperbolic metamaterials at the quantum level, and the ability to engineer and fabricate such structures. In particular, the research team is interested in developing quantum engineering methodologies through an approach which combines materials optimization, detailed optical studies and theoretical modeling. The project fosters a systematic investigation, starting from ab-initio modeling of thin films, followed by studies of multilayered systems, and subsequently a detailed study of patterned nano-photonic structures and devices. By combining skills in thin film synthesis, device fabrication and characterization, ultrafast optics and nano-photonics a comprehensive data set is obtained. Given the current trends for nanophotonics, device miniaturization and photonic-electronic integration, the ability to engineer new photonic materials is expected to significantly extend current applications of existing devices, enabling yet unforeseen implementations of quantum photonic metamaterials.

Liu 1604216
ABSTRACT

The research will develop a unique optical instrument for super resolution imaging at ultra-fast speed. The instrument will be the first optical imaging tool that has unprecedented resolution in both space (~50nm scale) and time (~20ms scale) simultaneously. It will have a profound impact to the fields of physical science, biomedical imaging and to fields where both high resolution and high speed optical imaging are required.

An innovative combination of plasmonics, structured illumination microscopy, and optical tweezers, will allow a host of fundamental studies on the nanoscale interactions and real-time dynamics of living cells that are impossible to conduct by any other presently available instrument. Localized plasmonic structured illumination (LPSIM) is a structured illumination microscopy (SIM) technique and the plasmonic antenna array provides deep sub-wavelength illumination patterns, leading to much higher resolution in a final reconstructed image.
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Nonlinear optics has been a rapidly growing scientific field in recent decades and holds promise for critical applications in optical information processing, telecommunications, and etc. Because the nonlinear coefficients for most materials are typically low, exploring new materials with higher nonlinear responses has always been one of the greatest challenges in this field. As a distinct research field, plasmonics has emerged as a novel approach to manipulate light at nanoscales. Recent advances in nanofabrication enable plasmonic structures at nanometer scales, leading to exceptionally high nonlinear responses due to the quantum size effect. This project aims to combine the field of quantum plasmonics with nonlinear optics to discover new optical materials with extremely high nonlinear responses and to apply such new materials for on-chip supercontinuum generation with an ultra-small footprint. This project involves fundamental science exploration, nano-material design and fabrications, on-chip supercontinuum generation device design and fabrication, and optical characterizations. This research will address fundamental issues at the cross-section of nanoplasmonics and nonlinear optics, and train graduate and undergraduate students in important areas of nanomaterials design and growth, optical characterization, device fabrication, nano-science, and nanotechnology. The transformative goal is to provide the scientific underpinnings of next generation integrated optical components based on engineered nanomaterials with extremely high nonlinearities. Research-based curriculum development, web-based dissemination of research results, journal publications and conference/workshop presentations, will impact more students including those at the pre-college level.
Technical description. This project addresses a new way to create strong nonlinear responses in a quantum engineered system and how to use it to build an ultra-compact supercontinuum generation device. The nonlinear optical properties of metal quantum wells will be systematically investigated. A dynamic quantum electrostatic model will be developed to accurately describe and predict the nonlinear responses of the metal quantum well systems. The state-of-the-art quantum plasmonic films will be fabricated at feature size down to 1-3 nm. Based on our theoretical estimation and preliminary experimental results, the quantum plasmonic systems will lead to the record high third order nonlinear susceptibility. The proposed quantum plasmonic waveguide-based supercontinuum generation devices, if successfully demonstrated, would be the first supercontinuum light source with micrometer footprint, enabling new opportunities for high-density integration and on-chip applications. Other than proposing specific individual concept and device, the PI envisions this project as a paradigm shift in the way a nonlinear material is constructed and implemented. Due to the large transition matrix elements and the high electron density in ultrathin metal films, quantum plasmonic structures can be tailored to possess extremely high nonlinear responses at desired operation frequencies. The outcome of this research will fill up knowledge void in both fields of plasmonics and nonlinear optics and pave the way to a new generation of strong nonlinear materials that may find important applications in integrated nonlinear optics.

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.

Non-technical Abstract:
Heat transfer is ubiquitous and plays an important role in our daily lives and industrial processes, such as cooling of computer chips and heating of buildings. In classical textbooks of thermal physics, it is well known that the dominant mode of heat transfer in solids is heat conduction, which is known to be slow (travels at around the speed of sound) and diffusive (non-directional). This project studies a new heat conduction mechanism that combines the light in vacuum and sound in solids to conduct heat at high speed (on the order of speed of light) and with a high degree of directionality. The study is important as it may contribute to diverse applications such as more efficient thermal management of computer chips, light emitting diodes, and buildings. By integrating photonics, thermal science, and nanotechnologies, the project provides an excellent interdisciplinary platform to educate and train female graduate students in physics and engineering and offers attractive hands-on laboratory experience for undergraduate and local high-school students from underrepresented minority groups.

Technical Abstract:
Heat conduction in solids is normally described as a diffusion process with short mean free path (MFP < 10 microns) associated with the main heat carriers, such as phonons and electrons. The goal of this project is to theoretically and experimentally investigate extraordinary thermal transport phenomena in a new regime of heat conduction mediated by surface phonon polariton (SPhP), which originates from the coupling between optical phonon and photon. SPhP is highly confined along the interface between a polar dielectric material and its surroundings and thus can carry high energy flux, comparable to or even higher than that of phonons in a solid. Under suitable conditions, SPhP can have extremely long propagation lengths (mm or longer) even at room and high temperature, and therefore, can exhibit extraordinary behaviors over a much longer distance. The project utilizes novel experimental techniques in nanoscale device fabrication and high-resolution nano-watt calorimetry, combined with rigorous theoretical modeling and numeric simulation, to explore extraordinary SPhP heat conduction phenomena in polar dielectric nanostructures, including low-dimensional heat conduction, non-diffusive and quantum thermal transport, and dynamically tunable thermal transport.

This Division of Materials Research (DMR) grant supports research to investigate extraordinary thermal transport phenomena in a new regime of heat conduction mediated by surface phonon polariton with funding from the Condensed Matter Physics (CMP) Program in the DMR of the Mathematical and Physical Sciences Directorate.

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.