Three MSE students win Rackham Predoctoral Fellowship Awards

MSE is proud to announce that three Ph.D. candidates - Wonjin Choi, Peter Meisenheimer, and Mohsen Taheri (ME) - have received Rackham Predoctoral Fellowships for the 2020-21 academic year.

The Rackham Predoctoral Fellowship is one of the most prestigious awards granted by the Rackham Graduate School. Each department (university-wide) can nominate up to three doctoral candidates, who are judged on the strength and quality of their dissertation abstract, publications and presentations, and recommendations.

“The Rackham Predoctoral Fellowship is an extremely competitive and highly coveted award,” said MSE graduate program advisor Renee Hilgendorf. “Having all three of our nominees selected is a true testament to the extraordinary caliber of our students.”

WONJIN CHOI

Terahertz circular dichroism (TCD) offers multifaceted spectroscopic capabilities for understanding the mesoscale chiral architecture and low-energy vibrations of macromolecules in (bio)materials. However, the lack of dynamic polarization modulators comparable to polarization optics for other parts of the electromagnetic spectrum is impeding the proliferation of TCD spectroscopy. Tunable optical elements fabricated from patterned plasmonic sheets with periodic kirigami cuts make possible the polarization modulation of terahertz radiation under application of mechanical strain. A herringbone pattern of microscale metal stripes enables a dynamic range of polarization rotation modulation exceeding 80° over thousands of cycles. Following out-of-plane buckling, the plasmonic stripes function as reconfigurable semi-helices of variable pitch aligned along the terahertz propagation direction. Several biomaterials, exemplified by an elytron of the Chrysina gloriosa, revealed distinct TCD fingerprints associated with the helical substructure in the biocomposite. Analogous kirigami modulators will also enable other applications in terahertz optics, such as polarization-based terahertz imaging, line-of-sight telecommunication, information encryption and space exploration.

PETER MEISENHEIMER

Meisenheimer's passion, and plan for the future, is to find new materials and design devices that can mitigate heating from electronics, saving a tremendous amount of energy in the long run. To this end, his research explores the frontiers of materials synthesis to engineer new, sustainable, non-volatile devices with unprecedented performance. His research centers around discovering new ferroic states in disorder-driven materials. This includes synthesis and characterization of new, magnetic, entropy-stabilized oxides and device implementation and optimization of existing composite multiferroic systems. Through these projects he has experience with many aspects of materials design, ranging from material deposition and basic characterization to nanolithography and coupled electronic measurements.

MOHSEN TAHERI (ME)

Taheri's research is looking into improving the fundamental relationships between the microstructures and mechanical properties are key to enhance the functional properties of metallic materials. The objective of his PhD research work is to utilize a combined multiscale experimental and computational framework to better understand the origins of the weakness in the mechanical properties of anisotropic metallic materials including 3-D printed metals and magnesium alloys. It is intended to (i) gain a fundamental understanding of the three-dimensional microstructural characteristic of metallic alloys, (ii) unravel the role of interfaces such as grain boundary and melt pool boundary on the mechanical response of materials (iii) develop a comprehensive computational model for accurately predicting the mechanical response of anisotropic metallic materials, and (iv) optimize the manufacturing process conditions to reinforce the mechanical response of metallic parts. Obtaining such unrivaled knowledge would provide the scientific underpinning crucial to the design of future metallic alloys.