1) Master degree from Moscow Institute of Physics and Technology, Russia. 2) Ph.D. in 2006 from the University of Pittsburgh, USA.
APPROACHES AND METHODS
Photonic Crystals are nanostructures with “crystal” like periodicities. They can be used to control light through a diffraction process. We control, “mold” light by using photonic crystals. 1) Calculations and numerical simulations: We developed new methods and software to calculate diffraction by Photonic (Colloidal) Crystals. 2) Fabrication: We fabricate photonic crystals thin films by self-assembling nanoparticles into a close-packed crystal structures using two methods: Vertical Deposition and Capillary Deposition methods. We also fabricate photonic crystals by self-assembling non-close-packed colloidal crystals and from liquid like colloidal crystals we synthesize non-close-packed solid colloidal crystals. We also fabricate and analyze monolayers of nano-spheres arranged in a 2D hexagonal lattice. 3) Characterization: we pioneered the use of angular resolved reflection spectroscopy to probe the structure and ordering of photonic crystals. We solved a long standing problem of the origin of diffraction dispersion lines observed in the specular reflection direction by a multiple-diffraction mechanism. We also found how to achieve the best ordering quality of colloidal crystals through manipulating the electrostatic repulsion strength between colloidal particles. 4) Practical applications: We found a new waveguiding effect in photonic crystals which will be useful for harvesting light for solar energy photovoltaic. We discovered that incident light can be efficiently concentrated and redirected along the surface of thin film photonic crystals.
ONGOING AND FUTURE WORK
We will continue to work on a) improving colloidal crystals ordering quality b) Calculate and compare with experiment diffraction by disordered photonic crystals c) Work to develop inexpensive coating to improve solar cells efficiency. Group: Dr. Maxim Kozlov (Ph.D), Assel Rakhmetova (BS), Yelbir Kazhkorim (BS) Funding: Currently there are 3 funded projects.
SELECTED RECENT PUBLICATIONS and PATENTS
1) A. Tikhonov, N. Kornienko, J. Zhang, L. Wang and S. A. Asher “Reflectivity Enhanced 2D Dielectric Particle Array Monolayer Diffraction”, J. Nanophotonics, Vol. 6, 063509 (2012).
2) U.S. Patent No. 13/553,555: J. Zhang, L. Wang, A. Tikhonov and S. A. Asher “Methods for making and compositions of two dimensional particle arrays” (2012).
3) J. Zhang, L. Wang, J. Luo, A. Tikhonov, N. Kornienko and S. A. Asher “2-D Array Photonic Crystal Sensing Motif”, J. Am. Chem. Soc., 133, 9152 (2011).
4) J. Bohn, A. Tikhonov and S. A. Asher, “Colloidal Crystal Growth Monitored By Bragg Diffraction Interference Fringes”, J. Colloid Interface Sci., 350, 381, (2010).
5) J. Bohn, M. Ben-Moshe, A. Tikhonov, D. Qu and S. A. Asher, “Charge stabilized crystalline colloidal arrays as templates for fabrication of non-close-packed inverted photonic crystals”, J. Colloid Interface Sci., 344, 298 (2010).
6) A. Tikhonov, J. Bohn and S. A. Asher, “Photonic crystal multiple diffraction observed by angular-resolved reflection measurements”, Phys. Rev. B. 80, 235125 (2009).
7) A. Tikhonov, R.D. Coalson and S.A. Asher, “Light diffraction from colloidal crystals with low dielectric constant modulation: Simulations using single-scattering”, Phys. Rev. B, 77, 235404 (2008).
8) A. Tikhonov, R. D. Coalson, Y. Dahnovsky, “Calculating Electron Current in a Tight-Binding Model of a Field-Driven Molecular Wire: Application to Xylyl-Dithiol”, J. Chem. Phys. 117, 567 (2002).
9) A. Tikhonov, R. D. Coalson, Y. Dahnovsky, J. Chem. Phys., “Calculating electron transport in a tight binding model of a field-driven molecular wire: Floquet theory approach”, J. Chem. Phys. 116, 10909 (2002).