Hastings' Research Group

News

New paper published in the International Journal of Hydrogen Energy

Schematic of bioreactor system.

Post-doctoral scholar Yuxia Ji (ChemE) and Ph.D. student Mansoor Sultan (ECE) recently published their work on clean hydrogren production from waste organic acids.  The effort combined photo-active bacteria, near-infrared illumination, and plasmonic nanoparticles and quantified hydrogen and CO2 production rates and efficiencies.  Professor Bhattacharyya (ChemE) led the research team which also included Professors Kim (Chemistry) and Hastings (ECE).  The work was conducted in collaboration with and through the support of Southern Company.  The research appeared in the International Journal of Hydrogen Energy, and can be accessed at https://doi.org/10.1016/j.ijhydene.2020.11.257.

New paper published in Optics Letters

Image of a metasurface for focussing and filtering.

Graduate students Mansoor Sultan and Fatih Balli, along with professors Lau and Hastings, recently published their work describing metasurfaces that can simultaneously focus and filter light.  These novel nanostructured optics may find application in imaging, spectroscopy, communications, or optical trapping.  The work appears in Optics Letters (https://doi.org/10.1364/OL.410080) and was supported by the National Science Foundation and Intel Corp.

New e-print on arXiv: Switchable X-ray Orbital Angular Momentum from an Artificial Spin Ice

An artificial spin ice generated x-ray beam carrying orbital angular momentum.

There is rapidly growing interest in X-ray orbital angular momentum (OAM) for imaging and probing materials at the nanoscale.  Recently, a team of researchers spanning the University of Kentucky and Lawrence Berkeley, Argonne, and Brookhaven National Laboratories found that X-ray diffraction from an antiferromagnetic (AF) metasurface gives rise to X-ray photons carrying OAM.  U.K. graduate student Justin Woods and postdoc Xiaoqian Chen (now at BNL) took leading roles in the effort and just released a preprint of their findings on arXiv (arXiv:2011.10148).  The results confirmed several predications about artificial spin lattices and their interactions with X-ray photons and suggest that AF metasurfaces can underpin designs for reconfigurable X-ray optics.

New paper in Nanotechnology: Real-time dose control for electron-beam lithography

Real-time feedback control for electron beam lithography.

Former UK ECE graduate students Yugu Yang and Stephen Maloney recently published their work on "Real-time dose control for electron-beam lithography" in Nanotechnology.  Electron-beam lithography is the primary patterning technique for integrated circuit mask making and low-volume manufacturing of nanoscale devices.  The electron dose controls the critical dimensions of transistors and other nanoscale features.  This paper describes the first step toward controlling this dose in real-time during patterning by using a fluorescent layer on the substrate.  The paper can be found at https://doi.org/10.1088/1361-6528/abcaca.

New e-print on arXiv: Hybrid Metasurfaces for Simultaneous Focusing and Filtering

Image of a metasurface for focussing and filtering.

UK graduate students Mansoor Sultan and Fatih Balli recently released an e-print of their paper "Hybrid Metasurfaces for Simultaneous Focusing and Filtering."  The paper described nanostructured, "flat" optics that simultaneously focus and filter light.  Similiar devices could find application in conventional or hyperspectral imaging.  The paper can be found at https://arxiv.org/abs/2009.07407.

National Nanotechnology Coordinated Infrastructure Award renewed for Kentucky Multiscale

The Kentucky Multiscale site of the National Nanotechnology Coordinated Infrastructure program was recently awarded a five year renewal by the National Science Foundation.  Kentucky Multiscale is a consortium of shared facilities at the University of Louisville and the University of Kentucky that provide cutting-edge instrumentation and expertise in advanced manufacturing and characterization from the nanoscale to the macroscole.  The award enables expanded access to the facilities along with a broad range of educational and outreach activities focused on nanoscale science and engineering.  Professor Kevin Walsh from the University of Louisville serves as the prinical investigatator on the award while Professor Hastings serves as the partner site co-PI at the University of Kentucky.  The full announcement can be found at NSF's website

New paper in Nature Communications: A Hybrid Achromatic Metalens

A Hybrid Achromatic Metalens and Near Infrared Images

U.K. graduate students Fatih Balli, Mansoor Sultan, and Sarah Lami just published their work on "flat optics" in Nature Communications.  Their paper, "A Hybrid Achromatic Metalens," describes lenses between 10 and 50 times thinner than a human hair.  The lenses image with light spanning a broad range of wavelengths in the near infrared.  The compact size, light weight, and mass manufacturabilty of metalenses make them ideal for mobile and airborne imaging, as well as for integration with optoelectronic systems for communications, computing, and medical diagnostics.  

Autovision 2020 to highlight Advanced Manufacturing Resources at the University of Kentucky and Louisville

The Autovision 2020 conference, hosted by the Kentucky Association of Manufacturers, will present a session on accessing advanced manufacturing resources at Kentucky Universities.  This will include highlights from several Ky Multiscale NNCI cores and a panel discussion.  The session is at 2pm on August 27, and Dr. Hastings will join the discussion with colleagues from UofL.  More details can be found at the Autovision 2020 website.

Research from Hastings and De Long groups featured in Science Briefs from Lawrence Berkeley National Laboratory's Advanced Light Source

Lawrence Berkeley National Laboratory's Advanced Light Source recently featured work from Dr. Hastings' and Dr. De Long's research groups in their "Science Briefs."  UK ECE postdoc Xiaoqian Chen and UK Physics graduate students Barry Farmer and Justin Woods took leading roles the effort which studied new phenomena in nanofabricated magnetic systems.  The work was supported by the U.S. Department of Energy under Award Number DE-SC0016519.

Recent Ph.D. graduate Sarah Lami publishes work on electron-beam induced etching in Nanotechnology.

Recent U.K. ECE Ph.D. graduate Sarah Lami has published an article entitled "Nanoscale focused electron beam induced etching of nickel using a liquid reactant" in the journal Nanotechnology.  The research, which introduces a new method for prototyping and repairing nickel nanostructures, was conducted in collaboration with Amrit Kahple (U.K. Physics), Nicolas Briot (U.K. Electron Microscopy Center), and Aurelien Botman (Thermo Fisher Scientific).

Graduate Students Sultan and Balli to present at SPIE Optics+Photonics

U.K. graduate students Mansoor Sultan and Fatih Balli will present their work on "flat" optics at the SPIE Optics+Photonics meeting in August.  Their abstracts can be found on the SPIE conference website.

"3D printed color focusing filters," Mansoor A. Sultan, Fatih Balli, Daniel L. Lau, J. Todd Hastings

"Rotationally tunable polarization-insensitive metasurfaces for generating vortex beams," Fatih Balli, Mansoor Sultan, J. Todd Hastings

New NSF RAPID Award

Motivated by the COVID-19 pandemic, the Hastings group has joined a new collaboration led by Dr. Bhattacharya (UK Chemical Engineering) to address the need for more breathable, antiviral masks.  See the UK Engineering news article for more information. The research is supported by a new NSF award  "RAPID: Antiviral Functionalized Membrane Mask and Nanostructured Materials for Corona Virus Capture and Deactivation." 

New paper in RSC Advances: Rhodopseudomonas palustris-based conversion of organic acids to hydrogen using plasmonic nanoparticles and near-infrared light

UK ECE graduate student Mansoor Sultan has just published a paper in collaboration with the Bhattacharyya (UK Chemical Engr.) and Kim (UK Chemistry) groups.  The paper addresses a new approach to clean energy production from waste streams using phototrophic bacteria and plasmonic nanoparticles.  The full paper can be found at https://doi.org/10.1039/C9RA08747H.

New paper in Physical Review Letters: Spontaneous Magnetic Superdomain Wall Fluctuations in an Artificial Antiferromagnet

UK ECE postdoc Xiaoqian Chen and UK Physics graduate students Justin Woods and Barry Farmer have published a new paper in Physical Review Letters entitled "Spontaneous Magnetic Superdomain Wall Fluctuations in an Artificial Antiferromagnet." The work was carried out in collaboration with researchers at Lawrence Berkeley National Laboratory, Argonne National Laboratory, and Brookhaven National Laboratory.  The effort used resonant, coherent soft X-ray scattering to study the behavior of nanomagnets in an artifical spin system.  The full paper can be found at https://doi.org/10.1103/PhysRevLett.123.197202.

New e-print on arXiv: A Hybrid Achromatic Metalens

UK Physics student Fatih Balli and UK ECE graduate students Mansoor Sultan and Sarah Lami have submitted an e-print entitled "A Hybrid Achromatic Metalens' that is currently under review for publication.  The paper presents a new approach to designing and fabricating "flat" optics that can focus and image over a broad range of near-infrared wavelengths.  The full paper can be found at https://arxiv.org/abs/1909.07941

New paper in Nanoscale: The radiation chemistry of focused electron-beam induced etching of copper in liquids

UK ECE graduate students Sarah Lami and Gabriel Smith, along with former Paul Lawrence Dunbar High School researcher Eric Cao, have just published a new paper related to nanoscale rapid prototyping and integrated circuit edit.  The full paper can be be found at https://doi.org/10.1039/C9NR01857C

New paper in Nanotechnology: Altering the radiation chemistry of electron-beam lithography with a reactive gas: a study of Teflon AF patterning under water vapor

UK ECE graduate students Mansoor Sultan and Sarah Lami, along with collaborators in UK Physics, have published a new paper in Nanotechnology entitled, "Altering the radiation chemistry of electron-beam lithography with a reactive gas: a study of Teflon AF patterning under water vapor."  The paper addresses a new approach to electron-beam lithography in which the exposure process is altered by the presence of water vapor.  The full paper can be found at https://doi.org/10.1088/1361-6528/ab16f7.