CAREER: Nonspherical, Active, and "Inverted" Bases for Optimized Photonic Crystal Design

Cornell University, Ithaca NY

Investigators

Abstract

Technical This project focuses on synthesis and characterization of inorganic colloids with tailoredmorphology and composition for greater understanding and fabrication of three-dimensional photonic crystal structures. New configurations and functionality will be explored through research on photonic crystals with nonspherical and active colloids as bases. Realization of photonic band gap materials (photonic crystals) operating in the near infrared and visible regions relies on ordered lattices of monodispersed, or uniform sized, nano- and mesoscale particles. This overcomes limitations of traditional colloidal building blocks such as silica (SiO2) and polystyrene spheres, which have poor optical function (low refractive index) and cannot produce the diverse packing arrangements necessary to fulfill the most promising enhancements in optical properties expected from photonic crystals. Monodispersed colloids with functionality (metals, semiconductors, magnetic ceramics, etc.) are promising for a variety of electrooptic applications, but have not been widely available. In the proposed research, techniques to expand colloid composition and morphology control will be studied to produce high refractive index monodispersed colloids including non-spherical, core-shell,hollow, and luminescent particles. Fields and templates made by lithography will be utilized in addition to self-assembly strategies to organize the particles. Modeling the assembly optical properties will enable refinement of the photonic crystal design requirements for several types of non-spherical building blocks. The research approach also includes the use of characterization techniques to image electromagnetic modes within the assemblies. Thus, theoretical photonic band calculations will be directly correlated with the structure and properties of the new photonic crystal materials. Better understanding of the effect of tailoring single particle properties (including symmetry reduction) on photonic band characteristics is sought and anticipated. Understanding of the relationship between material topology and function will aid in achieving new functional photonic crystal structures Non-Technical Broader Impact. Research will be closely integrated with education and outreach efforts. An outreach activity is proposed to build an appreciation for materials science and engineering at the pre-collegiate level through challenging "play" and cognitive activities that integrate art and technology. The jigsaw puzzle outreach to middle school students uses scanning electron microscopy art as a tool in science and engineering education. The PI also plans to incorporate her current research ideas and methods in fine particle technology and self-assembly into a new interactive course offering which will strengthen the linkage between graduate and undergraduate materials science and engineering education. The approach is novel and its evaluation has potential to enhance science studies research into engineering education. In addition, activities are planned that encourage female undergraduates attending Historically Black Colleges and Universities to engage in summer research experiences in nano- and mesoscale systems. This has the potential to strengthen network relationships between the Cornell University Department of Materials Science and Engineering and the physical science and engineering departments (and faculty) at minority serving institutions. It is also expected to lead to increased minority female graduate school applicants and admissions.