Professor Joseph Talghader is Fulbright Scholar and Optica Fellow
Fulbright Scholar Awards are highly distinguished and competitive fellowships that provide scholars unique opportunities for professionals, artists, and scholars to teach and conduct research abroad. Fulbright alumni include Nobel Laureates, Pulitzer Prize winners, MacArthur Fellows, and thousands of experts and leaders across academia and diverse fields in the private, public, and non-profit sectors. With the award, Talghader will establish and further the University of Minnesota’s connections with scholars, researchers, and potential students in Australia and around the world.
At the University of Minnesota, Talghader leads the Optical Micro and Nanosystems Laboratory. With funding from the United States Army Research, researchers in the lab have been working to develop uncooled thermal infrared sensors with performance close to that of cryogenically cooled detectors. The group recently developed uncooled metastructure detectors with record detectivity.
For the Fulbright scholarship, Talghader will probe the limits of a metastructure’s (a metastructure is a material with subwavelength patterns) ability to absorb any incident light. The project complements the research interests of Professor Lorenzo Faraone at the University of Western Australia who leads the Microelectronics Research Group. The MRG has crystal growth facilities that can grow the material that makes the best performance longwave infrared (LWIR) cryogenically cooled photodetectors and photoconductors. Talghader’s own expertise in LWIR thermal detectors (although a different class of LWIR detectors) will make significant contributions; the teams can draw on integrated metastructure absorbers for both detector classes.
During his time in Australia under the Fulbright program, Talghader will visit, lecture, and collaborate with multiple sites besides the UWA. These include the Defence Science and Technology Group, University of Adelaide, Australian National University, and University of Sydney.
Elevation to Optica Fellow
Late last year, Talghader was elevated to Fellow by Optica, formerly The Optical Society (OSA). The honor is a recognition of his research that has led to “advances in high optical power thin film physics and thermal infrared coating design.”
Working in the areas of optics and micro- and nano-mechanical systems, Talghader leads a research group that has been extensively involved in thermal infrared and radiation heat transfer devices, optical coatings materials science, and the miniaturization of micro-opto-mechanical systems. The highlights of the group’s work include: new ways to control the responsiveness and sensing wavelengths of standard uncooled infrared detectors; development of instrumentation to measure volcanic ash layers in glacier ice of Antarctica, developing stress and thermal expansion invariant coatings and negative thermal expansion thin films for matching zero expansion glasses, and projects that have led to adaptive mirrors with high heat transfer and coatings for lightweight mirrors and high power lasers.
Work conducted by Talghader’s research team between 2015 and 2019 contributed to the understanding of how the physics of the breakdown of an optic with surface particle contamination differs from that of clean optics under a short pulse or a continuous wave illumination. The outcome of this research has led to the recognition of material bandgap as more significant than thermal properties in predicting contamination-induced breakdown of an optic. This particular research, supported by the Directed Energy Joint Transition Office (DEJTO) Multidisciplinary Research Initiative (MRI), provided other findings too, all of which are now being used in the fabrication and design of high power laser coating materials.
Another high impact work led by the Talghader group is the development of wavelength tunable MEMS thermal detectors using a single absorbing layer in a transparent cavity that the group called “coupled-absorption cavities.” The group used the design to create a thermoelectric thermal detector for which they hold the record for the highest detectivity of any uncooled device. The design has also led to several patents. Currently infrared detectors developed by the group using the design have the highest absorption per unit mass of any planar subwavelength structures.
Talghader has also significantly contributed to multilayer coating design to minimize deformation due to stress and thermal expansion mismatch. Using atomic layer deposition (ALD), the Talghader group has designed coatings that can be deposited with the specific thermal expansion properties expected for specific applications.
Talghader has received multiple 3M Faculty Awards, the Antarctic Service Medal of the United States, and he has served on various program committees and reviews, including the triennial strategic planning panel for the Army Research Office Electronics Division, twice as program chair of the IEEE/LEOS Optical Microelectromechanical Systems Conference, and as guest editor of the IEEE Journal of Selected Topics in Quantum Electronics Special Issue on Optical Microsystems. He was conference chair of the IEEE/LEOS Optical MEMS and Nanophotonics Conference and served as lead editor of the JSTQE Special Issue on Optical Micro and Nanosystems. He is currently an editor of the NPG journal Light: Science and Applications.
Joseph Talghader earned his bachelor’s degree in electrical engineering from Rice University in Texas, and his master’s (1993) and doctoral degrees (1995) from the University of California at Berkeley. He worked at Texas Instruments as a Process Development Engineer, where he investigated EEPROM memory design and reliability issues. After graduating from Berkeley in 1995, he joined Waferscale Integration where he developed microfabrication processes for high-density nonvolatile memory devices. In 1997 Talghader joined the faculty at the University of Minnesota as an Assistant Professor and was later promoted to Associate and then Full Professor.