Boston Chapter of the IEEE Photonics Society

Wed
Apr 20, 2005
8:15 PM
 

MIT Lincoln Laboratory
 

Left-handed Electromagnetism in Photonic Crystals and Metamaterials

Dr. Patanjali Parimi, Northeastern University, Boston, MA

Abstract:  Electromagnetic waves display unusual properties in Left-Handed Materials (LHM), which possess a negative index of refraction. Two of the phenomena associated with negative refraction are: imaging by a flat lens; and slow wave propagation.  A metallic photonic crystal fabricated using cylindrical copper rods arranged on a triangular lattice demonstrates negative refraction with microwaves.  Negative refraction is observed in different frequency regimes between 7-10 GHz for incident beams along GðM and GðK directions of the first Brillouin zone.  The experimental results are in excellent agreement with band structure calculations and simulations of wave refraction.  A dielectric Photonic Crystal arranged on a square lattice demonstrates imaging by a flat lens.   Conventional optical systems have a single optical axis, limited aperture, and cannot focus light onto an area smaller than a square wavelength.  In contrast a photonic crystal flat lens does not have a unique optical axis and is not restricted by the aperture size. A particular advantage of a photonic crystalline material is its scalability to sub-micron dimensions ensuring several possible applications from microwave to optical frequencies.  Strong dispersion possessed by LHM leads to a slowing down of waves in photonic crystals.  Low group velocities of the order of c/100 are observed in a left-handed meta-material made of split ring resonators and wire strips. These results lead to the development of novel delay line filters, phase shifters, beam steerer, and lenses from microwave to optical frequencies.

Biography:  Patanjali V. Parimi has been an Associate Research Scientist in the Department of Physics at Northeastern University since 2001.  In 2001 he was an R&D consultant to Foster Miller, American Magnetics, and the Air Force Research Laboratories; from 1998-2001 he was a Post-doctoral Research Fellow at Northeastern University; from 1997-98 he was a Visiting Fellow, Tata Institute of Fundamental Research, Mumbai, India; and from 1993-98 he was a University Grants Commission Research Fellow, India.  He obtained his MS in Physics, and his Ph.D in Condensed Matter Physics from the University of Hyderabad, Hyderabad, India.  Science magazine selected his research on imaging by a flat lens as one of its breakthrough papers; Science, December 2003.  The American Physical Society-listed his research on left-handed meta-materials in the “Highlights of the Year 2003”, APS News, Vol. 13, February 2004.  The New Scientist, American Institute of Physics News, and Physics Today has quoted him for research on EM propagation in lefthanded metamaterials (2003).  He is the recipient of the Best Paper Award, "International Workshop on HTS - 10 years after its discovery", December 1996, Jaipur, India.  He has 26 publications in research journals, and has given 30 presentations or poster talks at universities and conferences