The high temperature superconductors which were discovered in 1986 still continue to pose major challenges to scientists. Not only is the mechanism for superconductivity not known, but the nature of the superconducting state and the motion of vortices continue to be debated intensely. We study the microwave response of superconductors, both for understanding the nature of superconductivity, the dynamics of vortices and for practical applications in microwave devices.

The principal areas of our research are:

  • Fundamental measurements and analysis of the penetration depth and surface impedance of superconductors, with a view to understanding the pairing state, the quasiparticle spectrum and the gap parameter
  • Vortex dynamics at high (rf and microwave) frequencies to obtain quantiative measurements of parameters such as pinning force constants, vortex viscosity, critical fields, melting and vortex glass transitions
  • Flux penetration and critical state dynamics
  • Josephson type nonlinear phenomena at microwave frequencies
  • Development of novel measurement techniques, such as the “hot finger” cavity method to measure surface impedance, tunnel diode technique of measuring penetration depth, patterned film structures to study vortex dynamics, modulated microwave absorption

The materials we study are the cuprate High Tc superconductors, borocarbides, and organic superconductors.

Our work in Superconductivity is supported by:

  • National Science Foundation
  • Division of Materials Research and Division of Electrical and Communications Systems, Rome Laboratory, Hanscom AFB (an AFOSR lab)

Related Publications

Show all

Sridhar, Srinivas; Dokmeci, Mehmet; Mosallaei, Hossein; Menon, Latika; Sokoloff, Jeffrey; Heiman, Don

Metamaterials and Conformal Antenna Technologies Technical Report

DTIC Document 2013.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Huang, YJ; Sridhar, S

Slow light using negative metamaterials Inproceedings

In: Active Photonic Materials IV, pp. 80951D, International Society for Optics and Photonics 2011.

Abstract | Tags: Metamaterials and Nanophotonics

Savo, Salvatore; Casse, BDF; Lu, Wentao; Sridhar, Srinivas

Observation of slow-light in a metamaterials waveguide at microwave frequencies Journal Article

In: Applied Physics Letters, vol. 98, no. 17, pp. 171907, 2011.

Abstract | Tags: Metamaterials and Nanophotonics

Ye, Yong-Hong; Huang, YJ; Lu, WT; Casse, BDF; Xiao, D; Bennett, SP; Heiman, D; Menon, L; Sridhar, S

Tuning the optical properties of metamaterials based on gold nanowire arrays embedded in alumina Journal Article

In: Optical Materials, vol. 33, no. 11, pp. 1667–1670, 2011.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, BDF; Lu, WT; Huang, YJ; Sridhar, S

Robust method to determine the resolution of a superlens by analyzing the near-field image of a two-slit object Journal Article

In: arXiv preprint arXiv:1105.0182, 2011.

Abstract | Tags: Metamaterials and Nanophotonics

Savo, Salvatore; Lu, Wentao T; Casse, Bernard Didier F; Sridhar, Srinivas

SLOW LIGHT IN NEGATIVE PERMEABILITY METAMATERIAL WAVEGUIDES Incollection

In: Selected Topics In Photonic Crystals And Metamaterials, pp. 373–387, 2011.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, Bernard Didier F; Sridhar, Srinivas

Superresolution imaging and superfocusing with negative-index metamaterials Journal Article

In: 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, BDF; Lu, WT; Huang, YJ; Gultepe, E; Menon, L; Sridhar, S

Super-resolution imaging using a three-dimensional metamaterials nanolens Journal Article

In: Applied Physics Letters, vol. 96, no. 2, pp. 023114, 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Huang, YJ; Casse, BDF; Banyal, RK; Sridhar, S

Storing light in active optical waveguides with single-negative materials Journal Article

In: Applied Physics Letters, vol. 96, no. 21, pp. 211112, 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Sridhar, S

Slow light, open-cavity formation, and large longitudinal electric field on a slab waveguide made of indefinite permittivity metamaterials Journal Article

In: Physical Review A, vol. 82, no. 1, pp. 013811, 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, Wentao T; Sridhar, Srinivas; Vodo, Plarenta; Parimi, Patanjali; Huang, Yongjian

Photonic crystal devices using negative refraction Miscellaneous

2010, (US Patent 7,808,716).

Abstract | Tags: Metamaterials and Nanophotonics

Casse, BDF; Lu, WT; Huang, YJ; Gultepe, E; Menon, L; Sridhar, S

Beating the diffraction limit using a 3D nanowires metamaterials nanolens Inproceedings

In: Frontiers in Optics, pp. FWO3, Optical Society of America 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Reynoso, F; Gultepe, E; Jhaveri, A; Kulkarni, P; Gershman, B; Ferris, C; Campbell, R; Harisinghani, M; Sridhar, S

TH-D-201C-08: Multi-Modal MRI SPECT and CT Imaging of Theranostic Nanoplatforms Journal Article

In: Medical Physics, vol. 37, no. 6Part8, pp. 3470–3470, 2010.

Tags: Metamaterials and Nanophotonics

Casse, Bernard Didier Frederic; Lu, Wentao; Huang, Yongjian; Gultepe, Evin; Menon, Latika; Sridhar, Srinivas

Superresolution Imaging Using a 3D Nanolens Made Up of Bulk Nanowires Metamaterials Journal Article

In: Bulletin of the American Physical Society, vol. 55, 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, Bernard Didier Frederic; Lu, Wentao; Huang, Yongjian; Gultepe, Evin; Menon, Latika; Sridhar, Srinivas

Superresolution Imaging Using a 3D Nanolens Made Up of Bulk Nanowires Metamaterials Inproceedings

In: APS Meeting Abstracts, 2010.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, BDF; Lu, WT; Banyal, RK; Huang, YJ; Selvarasah, S; Dokmeci, MR; Perry, CH; Sridhar, S

Imaging with subwavelength resolution by a generalized superlens at infrared wavelengths Journal Article

In: Optics letters, vol. 34, no. 13, pp. 1994–1996, 2009.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, Wentao T; Savo, Savatore; Casse, Didier B F; Sridhar, Srinivas

Slow microwave waveguide made of negative permeability metamaterials Journal Article

In: Microwave and Optical Technology Letters, vol. 51, no. 11, pp. 2705–2709, 2009.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Sridhar, S

Slow light, open cavity formation, and large longitudinal electric field on slab waveguide made of indefinite-index metamaterials Journal Article

In: arXiv preprint arXiv:0902.4482, 2009.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, Bernard Didier; Lu, Wentao T; Huang, Yongjian; Sridhar, Srinivas

Metallic Nanolens and III-V Nano-Optical Metamaterials Lenses for Subwavelength Imaging and Optoelectronics Applications Inproceedings

In: Optics and Photonics for Advanced Energy Technology, pp. ThC4, Optical Society of America 2009.

Abstract | Tags: Metamaterials and Nanophotonics

Sridhar, Srinivas; Lu, Wentao

Anisotropic metal-dielectric metamaterials for broadband all-angle negative refraction and superlens imaging Miscellaneous

2009, (US Patent App. 12/220,445).

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Sridhar, S

Electronic structure: Wide-band, narrow-band, and strongly correlated systems-Superlens imaging theory for anisotropic nanostructured metamaterials with broadband all-angle negative refraction Journal Article

In: Physical Review B Condensed Matter And Materials Physics, vol. 78, no. 23, pp. 233101, 2008.

Tags: Metamaterials and Nanophotonics

Lu, WT; Sridhar, S

Superlens imaging theory for anisotropic nanostructured metamaterials with broadband all-angle negative refraction Journal Article

In: Physical Review B, vol. 77, no. 23, pp. 233101, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Banyal, Ravinder; Casse, BDF; Lu, WT; Huang, YJ; Selvarasah, S; Dokmeci, M; Perry, CH; Sridhar, S

Experimental realization of a generalized superlens using negative refraction at infrared wavelengths Inproceedings

In: APS Meeting Abstracts, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Zhang, S; Huang, YJ; Sridhar, S

Effective medium theory of photonic crystals Inproceedings

In: APS Meeting Abstracts, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Huang, YJ; Lu, WT; Sridhar, S

Nanowire waveguide made from extremely anisotropic metamaterials Journal Article

In: Physical Review A, vol. 77, no. 6, pp. 063836, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Menon, L; Lu, WT; Friedman, AL; Bennett, SP; Heiman, D; Sridhar, S

Negative index metamaterials based on metal-dielectric nanocomposites for imaging applications Journal Article

In: Applied Physics Letters, vol. 93, no. 12, pp. 123117, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Menon, Latika; Lu, Wentao; Friedman, Adam; Bennett, Steven; Heiman, Donald; Sridhar, Srinivas

Negative Index Metamaterials for Superlenses Based on Metal-Dielectric Nanocomposites Inproceedings

In: APS Meeting Abstracts, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, BDF; Lu, WT; Huang, YJ; Sridhar, S

Nano-optical microlens with ultrashort focal length using negative refraction Journal Article

In: Applied Physics Letters, vol. 93, no. 5, pp. 053111, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Gultepe, Evin; Nagesha, Dattatri; Casse, Bernard Didier Frederic; Selvarasah, Selvapraba; Busnaina, Ahmed; Sridhar, Srinivas

Large scale 3D vertical assembly of single-wall carbon nanotubes at ambient temperatures Journal Article

In: Nanotechnology, vol. 19, no. 45, pp. 455309, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Casse, Bernard Didier F; Banyal, Ravinder K; Lu, WT; Huang, YJ; Selvarasah, Selvapraba; Dokmeci, M; Sridhar, Srinivas

Nanoengineering of a negative-index binary-staircase lens for the optics regime Journal Article

In: Applied Physics Letters, vol. 92, no. 24, pp. 243122, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, Wentao; Sridhar, Srinivas

Anisotropic nanostructured metamaterials for broadband all-angle negative refractionand flat lens imaging Inproceedings

In: APS Meeting Abstracts, 2008.

Abstract | Tags: Metamaterials and Nanophotonics

Huang, YJ; Lu, WT; Sridhar, S

Alternative approach to all-angle negative refraction in two-dimensional photonic crystals Journal Article

In: Physical Review A, vol. 76, no. 1, pp. 013824, 2007.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Huang, YJ; Vodo, P; Banyal, RK; Perry, CH; Sridhar, S

A new mechanism for negative refraction and focusing using selective diffraction from surface corrugation Journal Article

In: Optics express, vol. 15, no. 15, pp. 9166–9175, 2007.

Abstract | Tags: Metamaterials and Nanophotonics

Huang, YJ; Lu, WT; Sridhar, S

PART B-Quantum optics, physics of lasers, nonlinear optics, classical optics-Alternative approach to all-angle negative refraction in two-dimensional photonic crystals Journal Article

In: Physical Review-Section A-Atomic Molecular and Optical Physics, vol. 76, no. 1, pp. 13824–13824, 2007.

Tags: Metamaterials and Nanophotonics

Banyal, Ravinder; Casse, BDF; Vodo, Plarenta; Lu, WT; Sridhar, Srinivas

Nanophotonic structures for Negative Refraction at NIR and VIS Journal Article

In: APS, pp. X38–007, 2007.

Abstract | Tags: Metamaterials and Nanophotonics

Huang, YJ; Lu, WT; Sridhar, S

New approach to all-angle-negative-refraction in two-dimensional photonic crystals Journal Article

In: APS, pp. S38–002, 2007.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, Wentao; Vodo, P; Sridhar, Srinivas

Negative Refraction in Photonic Crystals Incollection

In: Physics of Negative Refraction and Negative Index Materials, pp. 133–147, Springer, Berlin, Heidelberg, 2007.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, Wentao; Sridhar, Srinivas

Determination of Refractive Indices of Photonic Crystals: Theory and Experiments Inproceedings

In: APS Meeting Abstracts, 2006.

Abstract | Tags: Metamaterials and Nanophotonics

Nagesha, Dattatri; Amiji, Mansoor M; Sridhar, Srinivas

Surface-Engineered Nanomaterials for Nanomedicine Inproceedings

In: ASME 2006 International Manufacturing Science and Engineering Conference, pp. 363–372, American Society of Mechanical Engineers Digital Collection 2006.

Abstract | Tags: Metamaterials and Nanophotonics

Vodo, P; Lu, WT; Huang, Y; Sridhar, S

Negative refraction and plano-concave lens focusing in one-dimensional photonic crystals Journal Article

In: Applied physics letters, vol. 89, no. 8, pp. 084104, 2006.

Abstract | Tags: Metamaterials and Nanophotonics

Vodo, Plarenta; Lu, Wentao; Parimi, Patanjali; Sridhar, Srinivas

Negative Refraction in One-Dimensional Photonic Crystal Inproceedings

In: APS Meeting Abstracts, 2006.

Abstract | Tags: Metamaterials and Nanophotonics

Vodo, Plarenta; Parimi, PV; Lu, WT; Sridhar, Srinivas

Focusing by planoconcave lens using negative refraction Journal Article

In: Applied Physics Letters, vol. 86, no. 20, pp. 201108, 2005.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, Wentao T; Sridhar, Srinivas

Flat lens without optical axis: Theory of imaging Journal Article

In: Optics express, vol. 13, no. 26, pp. 10673–10680, 2005.

Abstract | Tags: Metamaterials and Nanophotonics

Gennaro, E Di; Parimi, PV; Lu, WT; Sridhar, S; Derov, JS; Turchinetz, B

Slow microwaves in left-handed materials Journal Article

In: Physical Review B, vol. 72, no. 3, pp. 033110, 2005.

Abstract | Tags: Metamaterials and Nanophotonics

Sridhar, S; Parimi, PV; Lu, WT; Vodo, P; Derov, John S

Imaging and negative refraction in left-handed metamaterials Inproceedings

In: Metamaterials, pp. 595505, International Society for Optics and Photonics 2005.

Abstract | Tags: Metamaterials and Nanophotonics

Parimi, PV; Lu, WT; Vodo, P; Sokoloff, J; Derov, JS; Sridhar, S

Negative refraction and left-handed electromagnetism in microwave photonic crystals Journal Article

In: Physical review letters, vol. 92, no. 12, pp. 127401, 2004.

Abstract | Tags: Metamaterials and Nanophotonics

Vodo, Plarenta; Parimi, Patanjali V; Lu, Wentao T; Gennaro, Emiliano Di; Sridhar, Srinivas

Negative Refraction experiments in Photonic Crystal prisms Journal Article

In: APS, vol. 2004, pp. S19–008, 2004.

Abstract | Tags: Metamaterials and Nanophotonics

Lu, WT; Sokoloff, JB; Sridhar, S

Refraction of electromagnetic energy for wave packets incident on a negative-index medium is always negative Journal Article

In: Physical Review E, vol. 69, no. 2, pp. 026604, 2004.

Abstract | Tags: Metamaterials and Nanophotonics

Parimi, Patanjali; Vodo, Plarenta; Wentao, Lu; di Gennaro, Emiliano; Sridhar, Srinivas

Image formation by and wave propagation in a photonic crystal Inproceedings

In: APS Meeting Abstracts, 2004.

Abstract | Tags: Metamaterials and Nanophotonics

Vodo, P; Parimi, PV; Lu, WT; Sridhar, S; Wing, R

Microwave photonic crystal with tailor-made negative refractive index Journal Article

In: Applied physics letters, vol. 85, no. 10, pp. 1858–1860, 2004.

Abstract | Tags: Metamaterials and Nanophotonics