Presentation by Prof. Sajeev John

Photonic band gap(PBG) materials [1,2] are artificial periodic dielectric mictrostructures capable of
trapping light in 3D [3] on subwavelength scales without absorption loss. This offers new opportunities
for efficient solar energy trapping and harvesting in suitably micro-structured thin films [4-6]. It also
enables virtually complete control of the flow of light on microscopic scales in a 3D optical chip [7-9]
as well as very strong coupling of light to matter where desired. By further engineering the
electromagnetic density of states [10-12], it is possible to realize unprecendented coherent optical
control of the quantum state of resonant atoms or quantum dots [13,14].This defines fundamentally
new strong-coupling regime for quantum optics.
I review some of the underlying physics and numerical approaches to describing light trapping in
photonic crystals. I also discuss ongoing challenges to experimentally realize the consequences of
this remarkable effect.

1. S. John, Physical Review Letters 58, 2486 (1987).
2. E. Yablonovitch, Physical Review Letters 58, 2059 (1987).
3. S. John, Physical Review Letters 53, 2169 (1984).
4. A. Chutinan and S. John, Physical Review A 78, 023825 (2005).
5. G. Demesy and S. John, J. Appl. Physics (in press)
6. A. Deinega and S. John, J. Appl. Physics (submitted)
7. A. Chutinan, S. John and O. Toader, Phys. Rev. Lett. 90, 123901 (2003).
8. A. Chutinan and S. John, Physical Review B 72, 161316 (2005).
9. A. Chutinan and S. John, Optics Express A 14, 1266 (2006).
10. D. Vujic and S. John, Physical Review A 76, 063814 (2007).
11. R.Z. Wang and S. John, Physical Review A 70, 043805 (2004).
12. R.Z. Wang and S. John, J. Photonics and Nanostructures(Elsevier) 2, 137 (2004).
13. Xun Mia and S. John, Physical Review Letters 103, 233601 (2009).
14. Xun Mia and S. John, Physical Review A 80, 063810 (2009).