Graduate Student, Materials Science and Engineering

B.Tech 2003, Metallurgy and Materials Science
Indian Institute of Technology, Bombay

Office:
4115 MSEB

Telephone: 217-244-2460
E-mail: vramanan@uiuc.edu

 

Silicon-Air photonic crystals with embedded defects

There has been much interest in developing techniques to fabricate three-dimensional photonic crystals. Some of them are phase-mask lithography [1,2], colloidal self-assembly [3], two-photon polymerization [4], and direct writing [5]. We are interested in a versatile, inexpensive and quick method of creating wide area defect free crystals called holographic lithography [6-8]. This technique involves splitting a monochromatic plane wave from a laser into multiple beams and registering the interference pattern on to a photoresist that is placed at the interference volume. The lattice symmetry of the resultant structures depends on the wave vectors, polarizations, phases and intensities of each beam.

The integration of photonic crystals into optical components such as waveguides and optical transistors requires that the refractive index contrast is high and that one can introduce controlled defects in the crystal structure. Most photonic crystals fabricated by holographic lithography are polymer-air structures and have a low refractive index contrast. There have been attempts to convert these crystals to silicon-air [9,10], and there have been previous examples of the use of two photon polymerization to introduce features in a crystal [11]. We have demonstrated for the first time the ability to fabricate high quality silicon-air crystals with defect structures incorporated in them.

We used the interference pattern created by four beams in an umbrella configuration to fabricate Face Centered Cubic (FCC) like polymer-air photonic crystals. Defects are incorporated using Two Photon Polymerization and a triacrylate mixture. We use Atomic Layer Deposition (ALD) and low temperature Chemical Vapor Deposition (CVD) to create silicon–air inverse crystals.

References

[1] S. Jeon, E. Menard, M. Meitl, J. A. Rogers, Advanced Materials, 16, 1369 (2004)
[2] T. Y. M. Chan, O. Toader, S. John, Physical Review E, 73, 046610 (2006)
[3] A. Blanco, E. Chomski, S. Grabtchak, M. Ibisate, S. John, S. W. Leonard, C. Lopez, F.Meseguer,
     H. Miguez, J. P. Mondia, G. A. Ozin, O. Toader, H. M. van Driel, Nature, 405, 437 (2000)
[4] B. H. Cumpston, S. P. Ananthavel, S. R. Marder, J. W. Perry, Nature 398, 51 (1999)
[5] G. M. Gratson, M. Xu, J. A. Lewis, Nature, 428, 386 (2004)
[6] M. Campbell, D. N. Sharp, M. T. Harrison, R. G. Denning, A. J. Turberfield, Nature, 404, 53      (2000)
[7] S. Yang, M. Megens, J. Aizenberg, P. Wiltzius, P. M. Chaikin, W. B. Russel, Chemistry of      Materials, 14, 2831 (2002)
[8] C. K. Ullal, M. Maldovan, E. L. Thomas, G. Chen, Y. J. Han, S. Yang, Applied Physics Letters, 84,      5434 (2004)
[9] J. H. Moon, S. Yang, W. Dong, J.W. Perry, A. Adibi, Seung-Man Yang, Optics Express, 14, 6297      (2006)
[10] N. Tétreault, G. von Freymann, M. Deubel, M. Hermatschweiler, F. Pérez-Willard, S. John, M.        Wegener, G. A. Ozin, Advanced Materials, 18, 457 (2006)
[11] J. Scrimgeour, D. N. Sharp, C. F. Blanford, O. M. Roche, R. G. Denning, A. J. Turberfield,        Advanced Materials, 18, 1557 (2006)

People

• Prof. Pierre Wiltzius
• Dr. Masao Miyake
• Dr. Joe Geddes
• Robert Barry
• Andrew Brzezinski
• Christy Chen
• Sidhartha Gupta
• Vinayak Ramanan
• James Rinne