Research Interests

• Sculptured Thin Films --- Nano Engineered Thin Films.
• Surface Plasma Resonance.
• Transport properties of the materials.
• Conducting polymers and their applications.
• Optics, Lasers and their applications.

Sculptured Thin Films and Surface Plasmon Resonance: The first metallic thin film was made in 1885 by August Kundt by thermal evaporation. The film was birefringent that varied with porosity. In 1960, the images taken by scanning electron microscope revealed that such films were assembled by parallel nano wires. In 1990, with development in technology, better control on the growth of these films was achieved and instead of only straight nano wires, shaped nano wires were also grown. Now thin films can be fabricated with many different micro structures, like matchsticks, zigzags, coils, nematics, etc. They can be fabricated from metals, semiconductors and insulators. These films can be fabricated by thermal evaporation, arc evaporation, and sputtering etc. These thin films are essentially engineered on nano scales and are called Sculptured Thin Films (STFs). STFs are very interesting not only in their physical properties but also from their applications point of view.
Surface Plasmon Resonance (SPR) is a quantum-electromagnetic phenomenon arising from the interaction of light with free electrons at the planar interface of a metal and a dielectric material. The resonance arises as a result of transfer of energy carried by photons in the dielectric material to collective excitation, called plasmons, of free electrons in the metal at the interface. As the free electrons in the metal are coupled to the photons in the dielectric material, the quantum is called a Surface Plasmon-Polariton, SPP [1 – 3]. SPR has been extensively studied [3 – 5], particularly for sensing chemical and biochemical species. Typically, SPP is excited in a layer of a noble metal (silver or gold) and can be observed only for the parallel polarization of the incident laser beam, p-polarization (the direction of polarization lies in the plane of incidence) [3]. Recent theoretical studies [6 – 9] have shown that by replacing the homogenous dielectric material by a linear, anisotropic dielectric material, more than one SPP waves can be launched, and in the same film, SPP waves can be observed for s-polarization of the incident laser beam (the direction of polarization is perpendicular to the plane of incidence) [6,7]. Although these SPP waves propagate with the same frequency, they have different phase speeds, polarization states, attenuation rates and field distributions. Multiple SPP waves in a Chiral Sculptural Thin Film (CSTF) have been experimentally observed for p-polarized incident light [10].
My interest is to experimentally observe the multiple SPR guided by a metal-chiral Sculptured Thin Films (metal/CSTF) interface. This research will provide the experimental confirmation of the theoretical predictions of Motika, Polo, and Lakhtakia [6 – 9].
Related Publications:

• Surface Plasmon Resonance at the Interface of a Metal and Chiral Sculptured Thin Film, T. H. Gilani, Natalia Dushkina, W. L. Freeman, M. Z. Numan, D. N. Talwar and D. P. Pulsifer, Optical Engineering, Vol. 49, No. 12 (Dec. 2010).
• Anisotropic Properties of Sculptured Thin Films, Drew Pulsifer, Andrew Jones, and T. H. Gilani, Am. J. Undergrad. Res. 7/4 (March 2009) pp 17-20.

Transport properties of the materials and Conducting polymers and their applications: I am also interested in transport properties of the materials including electron and thermal transport properties and the effect of magnetic field and hydrostatic pressure on these properties. I am special interested in electrically conducting polymers and their applications. The conducting polymers are interesting both from basic physics and application point of views.
Controlling the synthesizing conditions can control most of the physical properties of the conducting polymers. For example, when Polypyrrole is doped with Hexaflourophosphate (PF6) and polymerized at a temperature lower than room temperature (~ 0 oC), it exhibits metallic conduction at temperature below 20 Kelvin. While the same when synthesized at room temperature exhibits semi-conducting behavior and even becomes insulator at very low temperature. Its room temperature conductivity can also be tuned by changing the synthesizing conditions. Similarly, doped Polyaceteylene has as high electrical conductivity as that of a good metal and so on.
I am also interested in exploring and investigating the possible applications of conducting polymers. After the discovery of highly conductive Polyacetylene by Shirakawa, et. al, in late seven tees, the research and applications of conductive polymers have attracted lot of interests (The chemistry Nobel prize,2000 was shared by physicist — Prof. A. Heeger on their pioneer work on conducting polymers). Today, Polythiophene derivatives are being used in antistatic treatment of photographic films and in devices to mark the products in supermarkets. Doped Polyaniline is being used as plastic carpet (antistatic) in operation theaters and offices. It is also used on computer screen as an electromagnetic shield. Polydialkylfluorenes are used in development of new color screen for television. Polymer LEDs are being used in flat television screens and in luminous traffic and information signs. These are only few examples of polymers applications. The conductive polymers will play a major roll in plasto-electronic revolution.
Conducting polymers have large number of potential applications. Their interesting property that they can be made insulating, semi conducting and highly conducting by proper polymerization, make them very attractive. For the proper exploitation of these organic materials understanding of their conduction mechanism is the key factor. Many applications may hinge around the understanding of mechanistic differences between these polymers and conventional materials (semi conductors and metals). My special interests are conduction mechanism, optical and thermal properties of these polymers, their applications as organic semi conductors (polymer LEDs, photovoltaic effect, active electronics), molecular electronics, etc.
Their applications in medical and sensor technology are also of interest. Using plasmon resonance technique, for example, it is possible to develop a sensitive opto-chemical detector based on conducting polymers.
Related Publications:

• Band Gap Energy in Silicon, G. Low, M. Kreider, D. Pulsifer, A. Jones, and T. H. Gilani, Am. J. Undergrad. Research, Vol 7, No. 1 (June 2008), 27-32.
• Evidence for Metal-like Electronic Contribution in Heat Capacity of Doped Polypyrrole, T. Gilani, J. Phys. Chem. B, 109/41 (2005), 19204-19207.
• Transport Properties of Doped Polypyrrole, T. H. Gilani, Frontiers in Physics, Proceeding of 6th National Symposium on Frontiers in Physics, Quaid-i-Azam Univ., Islamabad, Pakistan (Dec.16-18, 1997), 123-130.
• Low-temperature Metallic Conduction in PF6-doped Polypyrrole, T. H. Gilani and T.    Ishiguro, J. Phys. Soc. Jpn. 66/3 (1997), 727-737.
• Metallic State in Elongated PF6-doped Polypyrrole, T. H. Gilani and T. Ishiguro, Synth. Met. 84/1-3 (1997), 845-846.
• Low-temperature Hall Effect and Thermoelectric Power in PF6-doped Polypyrrole, T. H. Gilani, T. Masui, G. Yu. Logvenov and T. Ishiguro, Synth. Met. 78 (1996) 327-331.

My other research interests are optical properties of the materials, lasers and their applications.
Related Publications:

• The Undergraduate Optics Course at Millersville University, Tariq Gilani and Natalia Dushkina, Paper was presented at  the “Education and Training in Optics and Photonics” Confernce held  at St. Asaph, North Wales, UK, July 5th – 7th, 2009. The paper and was published in the proceedings of the conference.
• The study of the 1s4-2pn Optogalvanic Transients in a Neon Discharge Plasma, N. K. Piracha, R. Feaver, and T. H. Gilani, Optics Comm., Vol. 282, issue 13 (July 2009), pp. 2532 -- 2538.

References

• Dragoman M., and Dragoman D., Prog. Quantum Electron, 32 (2008) pp. 1 – 41.
• Maier, S.A., ‘Plasmonics: Fundamentals and Applications’, Springer, NY (2007).
• Homola, J., Yee, S.S., and Gauglitz, G., Sens. Actuators B: Chem., 54 (1999) pp. 3 – 15.
• Homola, J., ‘Surface Plasmon Resonance Based Sensors’, Springer, Heidelberg (2007).
• Abdulhalim, I., Zourob, M., and Lakhtakia, A., Electromagnetics, 28 (2008) pp. 214 – 242.
• Polo, A. Jr., and Lakhtakia, A., ‘On the surface plasmon ploriton wave at the planar interface of a metal and a chiral sculptured thin films’, Proc. R. Soc. A, 465 (2009) pp. 87 – 107.
• Polo, A.J. Jr., and Lakhtakia, A., ‘Energy flux in a surface plasmon-ploriton wave bound to the planar interface of a metal and a structurally chiral material’, J. Opt. Soc. Am. A, 26 (2009) pp. 1696 – 1703.
• Motyka, M.A., and Lakhtakia, A., J. Nanophoton., 2, 021910 (2008).
• Motyka, M.A., and Lakhtakia, A., J. Nanophoton., 3, 033502 (2009).
• Devender, Pulsifer, D.P., and Lakhtakia, A., Electronic Letters, 45/22 (2009) pp. 1137 – 1138.