Boston Chapter of the IEEE Photonics Society

Abstract:  Mid-infrared is one of the most important segments of the optical spectrum because it contains the "fingerprints" of most biological molecules. An explosion of near-field techniques (e.g., spectroscopy with sub-cellular resolution, labels-free detection) motivates the development of new sub-wavelength imaging tools. Experimental demonstration of a near-field super-lens in the mid-infrared (around 11 microns) range will be described. The lens is implemented using crystalline SiC films that have remarkable infrared properties: they support surface polaritons with less damping than most metals. Two demonstrations of super-lensing with lambda/20 spatial resolution will be demonstrated: (a) using FTIR microscopy [1], and (b) by direct near-field probing with NSOM [2]. Both amplitude and phase-sensitive imaging is demonstrated. It is also demonstrated that super-lensing can be used for sub-surface imaging. Applications to biologically-relevant imaging through water in nanofluidic channels will be discussed. In the second half of the talk, I will describe a novel imaging tool in IR/THZ: tapered multi-wire coaxial endoscope. Using a conventional coaxial waveguide (the ultimate sub-wavelength element!) as an inspiration,  I will demonstrate how two types of nanoscale imaging applications are enabled: image magnification and radiation focusing. In the first scenario, the tapered wire array acts as a multi-pixel TEM endoscope by capturing a detailed electromagnetic field profile created by deeply sub-wavelength objects at the endoscope's tip and magnifying it for observation.

The resulting imaging method is superior to the conventional scanning microscopy because of the parallel nature of the image acquisition by multiple metal wires. In the second scenario, the image of a large mask at the endoscope's base can be projected into a much smaller image at the tip, paving the way to novel lithographic techniques.

[1] D. Korobkin, Y.Urzhumov, and G.Shvets, "Enhanced Near-Field Resolution in Mid-Infrared Using Metamaterials", JOSA B 23, 467 (2006).

[2] T. Taubner, D.Korobkin, Y.Urzhumov, G.Shvets, and R.Hillenbrand, "Near-field microscopy through a SiC superlens", Science 313, 1595 (2006).

Biography:  Gennady Shvets is an Associate Professor of Physics at The University of Texas at Austin. He received his PhD in Physics from MIT in 1995. He has been on the Physics faculty at the University of Texas at Austin since 2004. Previously he has held research positions at the Princeton Plasma Physics Laboratory and the Fermi National Accelerator Laboratory, and was on the faculty of the Illinois Institute of Technology. His research interests include nano-photonics, meta-materials with exotic optical properties (especially negative index), near field optics, laser processing of materials on a nanoscale, and advanced particle accelerators. Dr. Shvets was a Department of Energy Postdoctoral Fellow in 1995-96. He was a recipient of the Presidential Early Career Award for Scientists and Engineers in 2000. His research is supported by DOE, NSF, DARPA, AFOSR, and ARO.