Hastings' Research Group

J. Todd Hastings

Reese Terry Professor of Electrical Engineering

Professor of Physics (joint appointment)

Director, Center for Nanoscale Science and Engineering

Contact:  todd.hastings@uky.edu

The Hastings Research Group seeks novel ways to increase the resolution, accuracy, and throughput of nanofabrication and nanomanufacturing techniques with a particular emphasis on photonics applications for sensing, imaging, and materials characterization. Collaborations have expanded the groups' investigations to renewable energy, data storage, communications, and computing.


New paper in Optics Letters describes Zoom Metalens

Scanning electron micrograph of a zoom metaens.

UK graduate Students Fatih Balli and Mansoor Sultan recently published their work on variofocal ("zoom") metalenses in Optics Letters.  Metalenses replace traditional bulky glass optics with thin, lightweight, patterned surfaces.  The metalens discussed in this paper consists of two "flat" optical elements whose mutual rotation allows the focal length to be adjusted.  The metalenses were fabricated using two-photon lithography, a type of nanoscale 3D printing. The work represents a first step toward building ultrathin, lightweight zoom lenses for mobile applciations.  The paper, entitled "Rotationally tunable varifocal 3D metalens," can be found at https://doi.org/10.1364/OL.426661.

New paper in Physical Review Letters highlighted in Physics Magazine

Postdoc Justin Woods and former postdoc Xiaoqian Chen's work, "Switchable X-Ray Orbital Angular Momentum from an Artificial Spin Ice," just appeared in Physical Review Letters.  The paper was also highlighted in Physics Magazine in a Viewpoint article entitled "Switching the Twist in X Rays with Magnets."   The research was conducted by a collabortive team from U.K.'s Electrical and Computer Engineering and Physics departments along with Lawrence Berkeley, Argonne, and Brookhaven National Laboratories.  So called “twisted” X-ray beams carry orbital angular momentum (OAM) and hold great promise for imaging and probing materials at the nanoscale.  In this work, we showed that a patterned array of nanoscale magnets, an artificial spin ice (ASI), can impart OAM to X-ray beams and that the beams can be switched on and off with temperature and magnetic field.  The research opens the possibility of using ASIs as reconfigurable X-ray optics, and switchable X-ray OAM beams could provide new tools for studying magnetic materials.

New paper in Nanophotonics describes visible-to-near infrared metalens

U.K. graduate students Fatih Balli and Mansoor Sultan just published their work on "flat optics" in Nanophotonics.  Their paper, "An Ultrabroadband 3D Achromatic Metalens," describes lenses 50 times thinner than a human hair.  The lenses image with light ranging from blue (450 nm) to the short-wave infrared (1700 nm).  The compact size, light weight, and mass manufacturabilty of metalenses make them ideal for mobile and airborne imaging.  The broadband capabilities of this lens are particularly well suited to emerging visible-to-short wave infrared camera technology.