Caldwell Nanophotonic Materials and Devices Lab


Prof. Joshua Caldwell, PhD

Dr. Joshua Caldwell was born in Attleboro, MA, graduating from Attleboro High School in 1995.  He left to undertake his undergraduate work at Virginia Tech in Blacksburg, VA, where he studied Chemistry.   During his time there, he served as a Manufacturing Engineer for ITT Night Vision in Roanoke, VA, working both on maintaining yields of microchannel plate fabrication and then later in R&D related to the next generation of filmless MCPs. He was awarded a Energy Research Undergraduate Laboratory Fellowship at the National Renewable Energy Lab in Golden, CO in the Summer of 1999.  There he worked under the direction of Michael Heben on ion milling of alumina templates for carbon nanotube growth. He was awarded his bachelors of Chemistry with a minor in History from Virginia Tech in 2000, at which time he got married, quit his job and moved to Florida.

He began his dissertation research during the Summer of 2000, focusing on magnetic resonance studies of electron-nuclear interactions withing two-dimensional electron systems.  Working under the direction of Prof. C. Russell Bowers in the Physical Chemistry Division at the University of Florida he had the opportunity to perform exciting fundamental research.  Following his graduation in December of 2004, Dr. Caldwell accepted a postdoctoral fellowship at the Naval Research Laboratory, where he was tasked with using optical spectroscopy and electronic testing as a means of understanding defect formation, nucleation and structure within wide-band gap semiconductors. There he worked under the direction of Dr. Orest Glembocki, within the group of Dr. Karl Hobart in the Electronic Science and Technology Division.

Dr. Caldwell was transitioned to permanent staff in 2007, where he began work in the field of nanophotonics, investigating coupling phenomena within plasmonic materials. It was at this time that he won his first major grant, becoming the youngest researcher to be awarded the highly competitive NRL Nanoscience Institute proposal which was ranked as the #1 proposal at NRL out of >110 proposals for that year. Dr. Caldwell, in collaboration with other NRL researchers developed the first method for dry transfer of graphene, demonstrating this with epitaxial graphene on silicon carbide using thermal release tape. A patent covering this technology won the Edison Award for top patent at NRL in 2014 and this is widely used commercially and in research.

Promoted to supervisory staff in 2012, Dr. Caldwell followed this up with another successful NSI proposal (ranked #7 out of >110 proposals), this time focused on understanding surface phonon polaritons and their potential for infrared optical components. This effort merged his prior work in wide band gap semiconductor materials with his more recent research in nanophotonics, leading to his efforts to use undoped, polar dielectric crystals for low-loss, sub-diffraction optics. This resulted in numerous publications, including a well-received review of the phonon polariton phenomena and another focusing on polaritons within two-dimensional materials. Dr. Caldwell was awarded  a sabbatical program by NRL in 2013 to work at the University of Manchester with Prof. Konstantin Novoselov, investigating the use of van der Waals crystals such as hexagonal boron nitride for mid-IR to THz nanophotonics. During this time, he demonstrated the natural hyperbolic response of hexagonal boron nitride, which has led to many additional findings.  Upon returning to NRL in 2014, he was awarded a third NSI proposal (ranked #3 out of >110 proposals), this time focused on identifying methods for creating new polaritonic materials through atomic-scale structuring and growth.

In 2017, Dr. Caldwell moved to Vanderbilt University, where he currently serves as a tenured Associate Professor of Mechanical Engineering, with affiliated status in Electrical Engineering and is part of the Interdisciplinary Materials Science program. He is focused on expanding the available library of nanophotonic materials and devices within the infrared to terahertz spectral range and in developing advanced infrared spectroscopic methods.

Prof. Caldwell has published over 140 papers, owns 10 patents and has given more than 95 invited talks and colloquia. He was elected a Fellow of the Materials Research Society in 2020 and is currently the Flowers’ Family Chancellor’s Faculty Fellow at Vanderbilt. He is an avid volunteer for multiple societies, serving on the Government Agency Subcommittee (former chair), Congressional Visits Day Subcommittee (vice chair) and Government Affairs Committee of the Materials Research Society, is a full member of the Electronic Materials Committee, and has helped organize multiple conferences and symposia.