Xu Research Group














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Prof. Xu’s group carries out research in two main areas: (1) nanoscale energy transport, and (2) nano-optics and laser-based nano-optical engineering.  



(1) Nanoscale energy transport


We investigate energy transport in nanoscale materials used for efficient energy conversion, including photovoltaic and thermoelectric energy conversion, and nanoscale materials for controlling - reducing or enhancing - thermal transport in nanoscale devices. At a microscopic level, energy transport and conversion is ultimately determined by the dynamics of interactions among basic energy carriers such as electrons, phonons, and photons, which occur at a time scale of femtosecond (fs, 10^-15 s) to picosecond (ps, 10^-12 s). We develop advanced femtosecond (fs) laser based high temporal (~ 10 fs) resolution experimental techniques (e.g., coherent phonon spectroscopy), Raman spectroscopy based thermometry, and high resolution (~ 10 nm) scanning probe based thermometry for the study of nanoscale energy transfer and conversion processes.


Current research projects include (details see Research Projects):

- Energy transport in 2D materials and nanoelectronic devices

- Near field radiation

- Ultrahigh resolution temperature mapping

- Energy transport in thermoelectric materials for waste heat recovery from automobile exhaust gas


 Also see Test Rig for TEG performance evaluation

 Also see News Release: Technology uses auto exhaust heat to create electricity, boost mileage




Doctoral student Vasudevan Iyer works with a Ultra fast laser at the Birck Nanotechnology Center to study energy transport in 2D materials





(2) Nano-optics and laser-based nano-optical engineering 


We are working on a broad range of topics related to nano-optics and nano-optical engineering. Our current effort is on laser-based nano-engineering using nanoscale optical antennas, which are developed in our laboratory. These antennas are capable of efficiently focusing light into a nanometer domain with intensity orders of magnitude higher than the incoming light intensity. Being able to concentrate light into a nanoscale domain with high intensity has numerous applications in nano-manufacturing, nanoscale imaging and diagnostics, and ultra-high density data storage. We also utilize femtosecond two-photon processes to develop rapid 3D nanoscale printing technologies.


Current projects in this area include (see details by following the link):

- Femtosecond rapid 3D printing
- Near-field radiation and nanostructures for efficient photovoltaic energy conversion

- Near-field scanning optical microscopy

- Parallel nanomaterials synthesis using nanoscale optical antenna and device development

- High density data storage using nanoscale optical antenna




Keywords: Nanoscale heat transfer, thermoelectrics, nano-optics, near-field optics, ultrafast laser, phonon spectroscopy, nano-manufacturing, nano-lithography, N/MEMS






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Copyright 2010, Prof. Xianfan Xu, Purdue University, all rights reserved.