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Joshua Caldwell

Associate Professor of Mechanical Engineering
Associate Professor of Electrical Engineering


Mechanical Engineering
Electrical Engineering and Computer Science (secondary)


Intellectual Neighborhoods

Research Focus

The Caldwell lab boasts a Fourier transform infrared (FTIR) system and attached microscope. Both the system and microscope have been custom modified to incorporate a Sterling-cooled bolometer and a series of MCT detectors that enable the measurements covering a the spectral range extending from 10-10,000 cm-1 (1,000 – 1 mm). The system can perform static or time-domain experiments and work in emission mode, quantifying thermal emission, luminescence or fluorescence in the infrared from micron scale areas of interest. Modulated spectroscopies such as photo and electroreflectance are also available for quantifying weak or forbidden optical transitions within semiconductor superlattices or atomic-scale two-dimensional materials. In addition, a custom-designed, variable angle attenuated total reflection tool capable of ATR, Kretschmann and Otto configuration experiments over the mid- to far-infrared is also available. The lab has expertise in the exfoliation and transfer of two-dimensional materials and heterostructures and has assisted in the development of the VINSE transfer tool for this purpose.

Biography

Dr. Caldwell obtained his B.A. in Chemistry in 2000 from Virginia Tech with a minor in History. Following this, he attended the University of Florida where he received his Ph.D. in Physical Chemistry in 2004. He accepted an American Society of Engineering Education Postdoctoral Fellowship to the US Naval Research Laboratory in 2005, where he was hired on as a staff scientist in 2007. He was promoted to a supervisory role in 2012. In 2013-2014 Dr. Caldwell worked with Prof. Kostya Novoselov at the University of Manchester during a Sabbatical, where they worked on identifying two-dimensional materials for infrared nanophotonics, identifying hexagonal boron nitride as a natural hyperbolic material. During his time at NRL he was the recipient of three highly competitive Nanoscience Institute Grants and several awards for his published works. In 2017 he accepted a tenured Associate Professorship in the Mechanical Engineering Department at Vanderbilt University.