Sajeev John

Theoretical Condensed Matter Physics and Quantum Optics

University Professor: Ph.D., Harvard (1984); Assistant Professor, Princeton (1986-89); S.B. M.I.T., (1979); NSERC Postdoctoral Fellow, University of Pennsylvania (1984-86); Consultant, Exxon Research (1985-89); Consultant, Bell Communication Research (1989); Principal Investigator, Photonics Research Ontario; Herzberg Medal (1995), McLean Senior Fellow (1996-present), Steacie Prize (1997), Killam Fellowship (1998-2000), Guggenheim Fellowship (2000-2001), Humboldt Senior Scientist Award (2000-present), King Faisal International Prize for Science 2001, Toronto Star, Physics Today, 2002 Premier's Platinum Award.

Condensed matter physics, disordered systems, optical properties, localization, many-body theory, magnetism, superconductivity.

Phone: (416) 978-3459 Fax: (416) 978-2537 e-mail: john at physics.utoronto.ca

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Research Interests

Photon Localization and Photonic Bandgaps

It has recently been demonstrated experimentally that in a new class of dielectrics (see movie clip) light can exhibit localization. We are studying the implications of localization in quantum-electrodynamics. This involves new phenomena such as photon-atom bound states as well as the reexamination of nonlinear optics, cooperative behaviour of atoms, laser activity and photo-chemistry in this context. These dielectric materials are the photonic analogs of semi-conductors and may have important technological applications. Discover Magazine Photonics Spectra

High Temperature Superconductivity

High Tc transition metal oxides constitute a major new frontier in solid state theory in which electron-electron interactions are not small compared to band effects. Novel collective effects in the electron spin field interact strongly with the electronic charge giving rise to what is known as a quantum spin liquid phase. We are investigating the nature of this new magnetic phase and possible origins of superconductive pairing.

A Microscopic Model for Non-Fermi-Liquid Behavior and D-Wave Charge Carrier Pairing in the Cuprates: A Slide Show

What Happens when Electrons Somersault? (An Overview Article)

Multiple Light Scattering Spectroscopy

In disordered media, multiple scattering of light leads to complication for spectroscopic studies. Recently, we have developed a theory that enables the reconstruction of the dynamic structure factor of the medium from a light scattering experiment. A major application is the use of photon diffusion as a diagnostic tool for metabolic imaging in medicine. We are currently trying to refine this spectroscopic tool to detect tumors in biological tissue. Another important application is in the understanding of the newly discovered ''Laser Paints''

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Current Research Program

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Current Members of the Research Group

Former Ph.D. Students

Current Ph.D. Students

  • James Bauer
  • Shengjun Yang
  • Xun Ma
  • Stephen Foster
  • Abdullah Al-Rashid

Current Postdocs

  • Guillaume Demesy
  • Ramy El-Ganainy
  • Wah-Tung Lau
  • Alexei Deinega
  • Rongjuan Liu
  • Alagappan Gandhi
* McLean Junior Fellow

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Selected Publications

  1. "Electromagnetic Absorption in a Disordered Medium near a Photon Mobility Edge", Sajeev John, Phys. Rev. Lett. 53, 2169 (1984). ABSTRACT PDF
  2. "Spin Glass State of a Randomly diluted Granular Superconductor", Sajeev John and T.C. Lubensky, Phys. Rev. Lett. 55, 1014 (1985). ABSTRACT PDF
  3. "Theory of the Electron Band Tails and the Urbach Optical Absorption Edge", Sajeev John, C. Soukoulis, Morrel H. Cohen and E.N. Economou, Phys. Rev. Lett. 57, 1777 (1986). ABSTRACT PDF
  4. "Strong Localization of Photons in Certain Disordered Dielectric Superlattices", Sajeev John, Phys. Rev. Lett. 58, 2486 (1987). ABSTRACT PDF
  5. "Localization and the Density of States for an Electron in a Quantized Elastic Continuum", Sajeev John, Physical Review B 35, 9291 (1987). ABSTRACT PDF
  6. "Density of States for an Electron in a Correlated Gaussian Random Potential: Theory of the Urbach Tail", Sajeev John, M.Y. Chou, M.H. Cohen and C.M. Soukoulis, Phys. Rev. B 37, 6963 (1988). ABSTRACT PDF
  7. "Temperature Dependence of the Urbach Edge: A Theory of Multiple Phonon Absorption and Emission Sidebands", C. Grein and Sajeev John, Phys. Rev. B 39, 1140 (1989). ABSTRACT PDF
  8. ''Localization of Light'', S. John, Physics Today, May (1991), Cover Story.
  9. ''Quantum Electrodynamics Near a Photonic Band Gap: Photons Bound States and Dressed Atoms'', S. John and J. Wang, Phys. Rev. Lett. 64, 2418 (1990). ABSTRACT PDF
  10. ''Nonlinear Optical Solitary Waves in a Photonic Bandgap'', S. John and N. Akozbek, Physical Review Letters 71, 1168 (1993). ABSTRACT PDF
  11. ''Topological Magnetic Solitons in the Two-Dimensional Mott-Hubbard Gap'', S. John and A. Golubentsev, Physical Review Letters 71, 3343 (1993). ABSTRACT PDF
  12. "Spontaneous Emission near the Edge of a Photonic Bandgap", Sajeev John and Tran Quang, Physical Review A 50 1764 (1994). ABSTRACT PDF
  13. "Spin-flux and Magnetic Solitons in an Interacting Two-Dimensional Electron Gas: Topology of Two-Valued Wavefunctions", Sajeev John and A. Golubentsev, Physical Review B51, 381 (1995). ABSTRACT. PDF
  14. ''Localization of Superradiance near a Photonic Bandgap'', S. John and T. Quang, Phys. Rev. Lett. 74, 3419 (1995). ABSTRACT PDF
  15. ''Optical Coherence Propagation and Imaging in a Multiple Scattering Medium'', S. John, G. Pang and Y. Yang, Journal of Biomedical Optics 1, number 2, 180 (1996). ABSTRACT
  16. ''Quantum Optical Spin-Glass State of Impurity Two-Level Atoms in a Photonic Bandgap'', S. John and T. Quang, Phys. Rev. Lett. 76, 1320 (1996). ABSTRACT PDF
  17. ''Resonant Nonlinear Dielectric Response in a Photonic Band Gap Material'', S. John and T. Quang, Phys. Rev. Lett. 76, 2484 (1996). ABSTRACT PDF
  18. ''Theory of Lasing in a Multiple Scattering Medium'', S. John and G. Pang, Physical Review A 54, 3642 (1996). ABSTRACT PDF
  19. "Collective Switching and Inversion without Fluctuation of Two-Level Atoms in Confined Photonic Systems", Sajeev John and Tran Quang, Physical Review Letters 78, 1888 (1997). ABSTRACT PDF POSTSCRIPT
  20. "Multiphoton Localization and Propagating Quantum Gap Solitons in a Frequency Gap Medium", Sajeev John and Valery Rupasov, Physical Review Letters 79, 821 (1997). ABSTRACT PDF POSTSCRIPT
  21. "Coherent Control of Spontaneous Emission Near a Photonic Band Edge: A Single-Atom Optical Memory Device", Tran Quang, M. Woldeyohannes, Sajeev John and G.S. Agarwal, Physical Review Letters 79 5238 (1997). ABSTRACT PDF POSTSCRIPT
  22. "Frozen Light", Sajeev John, Nature 390, 661 (1997). ABSTRACT
  23. "Charged Bosons in a Doped Mott Insulator: Electronic Properties of Domain Wall Solitons and Meron-Vortices", Mona Berciu and Sajeev John, Physical Review B 57 9521 (1998). ABSTRACT PDF POSTSCRIPT
  24. "Midgap States of a Two-Dimensional Antiferromagnetic Mott Insulator: Electronic Structure of Meron-Vortices", Sajeev John, Mona Berciu and A. Golubentsev, Europhysics Letters 41 (1), 31 (1998). ABSTRACT PDF
  25. "Photonic Band Gap Formation in Certain Self-Organizing Systems", Kurt Busch and Sajeev John, Physical Review E 58, 3896 (1998). ABSTRACT PDF POSTSCRIPT
  26. "Liquid Crystal Photonic Band Gap Materials: The Tunable Electromagnetic Vacuum", Kurt Busch and Sajeev John, Physical Review Letters 83 (5), 967-970 (1999). ABSTRACT PDF POSTSCRIPT
  27. "Coherent control of spontaneous emission near a photonic band edge: A qubit for quantum computation", Mesfin Woldeyohannes and Sajeev John, Physical Review A 60(6), 5046-5068 (1999). ABSTRACT PDF POSTSCRIPT
  28. "Quantum dynamics of charged and neutral magnetic solitons: Spin-charge separation in the one-dimensional Hubbard model", Mona Berciu and Sajeev John, Physical Review B 61 (15), 10015-10028 (2000). ABSTRACT PDF
  29.   POSTSCRIPT
  30. "A microscopic model for d-wave charge carrier pairing and non-Fermi-liquid behavior in a purely repulsive 2D electron system", Mona Berciu and Sajeev John, Physical Review B 61 (24), 16454-16469 (2000). ABSTRACT PDF
  31.   POSTSCRIPT
  32. "Large-scale synthesis of a silicon photonic crystal with a complete three-dimensional bandgap near 1.5 micrometres", Alvaro Blanco, Emmanuel Chomski, Serguei Grabtchak; Marta Ibisate, Sajeev John, Stephen W. Leonard, Cefe Lopez, Francisco Meseguer, Hernan Miguez, Jessica P. Mondia, Geoffrey A. Ozin, Ovidiu Toader and Henry M. van Driel, Nature 405 (6785), 437-440 (2000). ABSTRACT PDF
  33. "Optical Trapping, Field Enhancement, and Laser Cooling in Photonic Crystals", Ovidiu Toader, Sajeev John and K. Busch, Optics Express vol.8, no. 3, pg 271- (2001). ABSTRACT PDF
  34. "Proposed Square Spiral Microfabrication Architecture for Large Three-Dimensional Photonic Band Crystals", Ovidiu Toader and Sajeev John, Science vol. 292, 1133 (2001).   ABSTRACT   PDF
  35. "Photonic Band Gap Materials: Towards an All-Optical Micro-Transistor", Sajeev John and Marian Florescu, Journal of Optics A: Pure and Applied Optics 3, S103 (2001). ABSTRACT   PDF
  36. "Theory of Fluorescence in Photonic Crystals", Nipun Vats, K. Busch, Sajeev John, Physical Review A 65, 043808 (2002). ABSTRACT   PDF  POSTSCRIPT
  37. "Coherent Control of Spontaneous Emission near a Photonic Band Edge", M. Woldeyohannes and Sajeev John, Journal of Optics B: Quantum and Semiclass. Opt. 5, R43-R82 (2003).   PDF
  38. "Diffractionless Flow of Light in All-Optical Micro-chips", A. Chutinan, Sajeev John, and O. Toader, Physical Review Letters 90, 123901 (2003) .   ABSTRACT PDF POSTSCRIPT
  39. "Photonic Band Gap Materials based on Tetragonal Lattices of Slanted Pores", O. Toader, M. Berciu, and Sajeev John, Physical Review Letters 90, 233901 (2003). ABSTRACT  PDF POSTSCRIPT
  40. "Optical Properties of a Silicon Square Spiral Photonic Crystal" , S. Kennedy, M. Brett, O. Toader, and Sajeev John, Journal of Photonics and Nanostructures, Vol. 1, Issue 1, 37 (2003). PDF
  41. "Photonic Band Gap Synthesis by Holographic Lithography" Ovidiu Toader, Tim Chan, and Sajeev John, Physical Review Letters 92, 043905 (2004). ABSTRACT  PDF POSTSCRIPT
  42. "Theory of Photon Statistics and Optical Coherence in a Multiple-Scattering Random Laser Medium", Lucia Florescu and Sajeev John, Physical Review E 69, 046603 (2004). ABSTRACT  PDF  POSTSCRIPT
  43. "Theory of a One-Atom Laser in a Photonic Band Gap Micro-chip", Lucia Florescu, Sajeev John, Tran Quang, and R.Z. Wang, Physical Review A 69, 013816 (2004). ABSTRACT PDF  POSTSCRIPT
  44. "Photonic band gap enhancement in frequency-dependent dielectrics", Ovidiu Toader and Sajeev John, Physical Review E 70, 046605 (2004). ABSTRACT PDF
  45. "Photon Statistics and Optical Coherence Properties of Light Emission from a Random Laser", Lucia Florescu and Sajeev John, Physical Review Letters 93, 013602 (2004).. ABSTRACT  PDF
  46. "Magnetic structure factor in cuprate superconductors: Evidence for charged meron vortices", Mona Berciu and Sajeev John, Physical Review B 69, 224515 (2004). ABSTRACT PDF
  47. "Engineering the Electromagnetic Vacuum for Controlling Light with Light in a Photonic Band Gap Micro-chip", R. Z. Wang and Sajeev John, Physical Review A 70, 043805 (2004). ABSTRACT PDF
  48. "Diffractionless Flow of Light in 2D-3D Photonic Band Gap Hetero-structures: Theory, Design Rules, and Simulations", Alongkarn Chutinan and Sajeev John, Physical Review E 71, 026605 (2005). ABSTRACT PDF
  49. "Pulse re-shaping in photonic crystal waveguides and micro-cavities with Kerr-nonlinearity: Critical Issues for all-optical switching", Dragan Vujic and Sajeev John, Physical Review A 72, 013807 (2005). ABSTRACT  PDF
  50. "Slanted Pore Photonic Band Gap Materials", Ovidiu Toader and Sajeev John, Physical Review E 71, 036605 (2005). ABSTRACT  PDF
  51. "Light Localization for Broadband Integrated Optics in Three Dimensions", A. Chutinan and Sajeev John, Physical Review B 72, 16, 161316 (2005). ABSTRACT PDF
  52. "Elastic Photonic Crystals: From Colour Fingerprinting to Enhancement of Photoluminescence", A. Arsenault, T. J. Clark, G. Von Freymann, E. Vekris, L. Cademartiri, S. Wong, V. Kitaev, I. Manners, Sajeev John, G. A. Ozin, Nature Materials 5 (3): 179-184 March (2006). PDF
  53. "New route towards three-dimensional photonic band gap materials: Silicon double inversion of Polymeric Templates", N. Tetreault, G. von Freymann, M. Deubel, M. Hermatschweiler, F. Perez-Willard, Sajeev John, M. Wegener, G.A. Ozin, Advanced Materials 18 (4): 457, Feb 17 (2006). ABSTRACT
  54. "Direct Laser Writing of Three-Dimensional Photonic Crystals in High Index of Refraction Chalcogenide Glasses", G. von Freymann, S. Wong, G. A. Ozin, Sajeev John, F. Perez-Willard, M. Deubel, M. Wegener, Advanced Materials Vol. 18, Issue 3, February, 2006, Pages: 265-269. ABSTRACT
  55. "3+1 Dimensional Integrated Optics with Localized Light in a Photonic Band Gap", A Chutinan and Sajeev John, Optics Express 14 (3): 1266-1279, Feb 6, (2006). ABSTRACT  PDF
  56. "3D-2D-3D photonic crystal heterostructures by direct laser writing", M. Deubel, M. Wegener, S. Linden, G. Von Freymann, and Sajeev John, Optics Letters 31 (6): 805-807 March 15 ( 2006) ABSTRACT  PDF
  57. "Photonic band-gap formation by optical-phase-mask lithography", Timothy Y. M. Chan, Ovidiu Toader, and Sajeev John, Physical Review E 73, 046610 (2006) ABSTRACT PDF
  58. ''Nonlinear Bloch waves in resonantly doped photonic crystals'', Artan Kaso and Sajeev John, Physical Review E 74, 046611 (2006) ABSTRACT  PDF
  59. "Localized light orbitals: Basis states for three-dimensional photonic crystal microscale circuits", Hiroyuki Takeda, Alongkarn Chutinan and Sajeev John, Physical Review B 74, 195116 (2006).   ABSTRACT  PDF  POSTSCRIPT
  60. "Diamond photonic band gap synthesis by umbrella holographic lithography", Ovidiu Toader, Timothy Y. M. Chan, and Sajeev John, Appl. Phys. Lett. 89, 101117 (2006); doi:10.1063/1.2347112 (3 pages)   ABSTRACT  PDF
  61. "Electromagnetically Induced Exciton Mobility in a Photonic Band Gap", Sajeev John and Shengjun Yang, Physical Review Lett. 99 , 046801 (2007).   ABSTRACT PDF
  62. "Exciton dressing and capture by a photonic band edge", Shengjun Yang and Sajeev John, Physical Review B 75, 235332 (2007).   ABSTRACT PDF
  63. "Molding light flow from photonic band gap circuits to microstructured fibers", James Bauer and Sajeev John, Applied Physics Letters 90, 261111 (2007).   ABSTRACT PDF
  64. "Nonlinear Bloch waves in metallic photonic band-gap filaments", Artan Kaso and Sajeev John, Physical Review A 76, 053838 (2007). ABSTRACT PDF
  65. "Coherent all-optical switching by resonant quantum-dot distributions in photonic band-gap waveguides", Dragan Vujic and Sajeev John, Physical Rreview A 76, 063814 (2007).  ABSTRACT PDF
  66. "Broadband optical coupling between microstructured fibers and photonic band gap circuits: Two-dimensional paradigms", James Bauer and Sajeev John, Physical Review A 77, 013819 (2008)  ABSTRACT PDF
  67. "Compact optical one-way waveguide isolators for photonic-band-gap microchips", Hiroyuki Takeda and Sajeev John, Physical Review A 78, 023804 (2008)   ABSTRACT PDF
  68. "Light trapping and absorption optimization in certain thin-film photonic crystal architectures", Alongkarn Chutinan and Sajeev John, Physical Review A 78, 023825 (2008)   ABSTRACT PDF
  69. "Templating and Replication of Spiral Photonic Crystals for Silicon Photonics", Kock Khuen Seet, Vygantas Mizeikis, Kenta Kannari, Saulius Juodkazis, Hiroaki Misawa, Nicolas Tetreault, and Sajeev John, IEEE Journal of Selected Topics in Quantum Electronics, Vol. 14, No. 4, July/August (2008).  PDF
  70. "Circuits for light in holographically defined photonic-band-gap materials", Timothy Y. M. Chan and Sajeev John, Physical Review A 78, 033812 (2008).   ABSTRACT  PDF
  71. "Exceptional Reduction of the Diffusion Constant in Partially Disordered Photonic Crystals", Costanza Toninelli, Evangellos Vekris, Geoffrey A. Ozin, Sajeev John and Diederik S. Wiersma, Physical Review Letters, 101, 123901 (2008).  ABSTRACT  PDF
  72. "Metallic photonic-band-gap filament architectures for optimized incandescent lighting", Sajeev John and Rongzhou Wang, Physical Review A, 78, 043809 (2008).  ABSTRACT  PDF
  73. "Optical wavelength converters for photonic band gap microcircuits", Dragan Vujic and Sajeev John, Physical Review A 79, 053836 (2009). ABSTRACT  PDF
  74. "Ultrafast Population Switching of Quantum Dots in a Structured Vacuum", Xun Ma and Sajeev John, Physical Review Lett. 103, 233601 (2009). ABSTRACT  PDF
  75. "Switching dynamics and ultrafast inversion control of quantum dots for on-chip optical information processing", Xun Ma and Sajeev John, Physical Review A 80, 063810 (2009). ABSTRACT  PDF
  76. "Microscopic theory of multiple-phonon-mediated dephasing and relaxation of quantum dots near a photonic band gap", Chiranjeeb Roy and Sajeev John, Physical Review A 81, 023817 (2010). ABSTRACT  PDF
  77. "Self-consistent Maxwell-Bloch theory of quantum-dot-population switching in photonic crystals", Hiroyuki Takeda and Sajeev John, Physical Review A 83, 053811 (2011). ABSTRACT  PDF
  78. "Coherence and antibunching in a trapped interacting Bose-Einstein condensate", Shengjun Yang and Sajeev John, Physical Review B 84, 024515 (2011). ABSTRACT  PDF
  79. "Quantum-dot all-optical logic in a structured vacuum", Xun Ma and Sajeev John, Physical Review A 84, 013830 (2011). ABSTRACT  PDF
  80. "Optical pulse dynamics for quantum-dot logic operations in a photonic-crystal waveguide", Xun Ma and Sajeev John, Physical Review A 84, 053848 (2011). ABSTRACT  PDF
  81. "Anomalous flow of light near a photonic crystal pseudo-gap", Kyle M. Douglass, Sajeev John, Takashi Suezaki, Geoffrey A. Ozin, and Aristide Dogariu1, Optics Express, 19, No. 25 , 25321 (2011). ABSTRACT  PDF
  82. "Sculpturing of photonic crystals by ion beam lithography: towards complete photonic bandgap at visible wavelengths", Saulius Juodkazis, Lorenzo Rosa, Sven Bauerdick, Lloyd Peto, Ramy El-Ganainy and Sajeev John, Optics Express, 19, No. 7 , 5803 (2011). ABSTRACT  PDF
  83. "Effective optical response of silicon to sunlight in the finite-difference time-domain method", Alexei Deinega and Sajeev John, Optics Letters, 37, No. 1 112 (2012). ABSTRACT  PDF
  84. "Solar energy trapping with modulated silicon nanowire photonic crystals", Guillaume Demesy and Sajeev John, J. Appl. Phys., 112, 074326 (2012). ABSTRACT  PDF
  85. "Solar power conversion efficiency in modulated silicon nanowire photonic crystals", Alexei Deinega and Sajeev John, J. Appl. Phys. 112, 074327 (2012). ABSTRACT  PDF
  86. "Light-trapping in dye-sensitized solar cells", Stephen Foster and Sajeev John, Energy Environ. Sci., DOI: 10.1039/C3EE40185E (2013). ABSTRACT  PDF
  87. "Solar light trapping in slanted conical-pore photonic crystals: Beyond statistical ray trapping", Sergey Eyderman, Sajeev John and Alexei Deinega, J. Appl. Phys. 113, 154315 (2013); doi: 10.1063/1.4802442. ABSTRACT  PDF
  88. "Coupled optical and electrical modeling of solar cell based on conical pore silicon photonic crystals", Alexei Deinega, Sergey Eyderman, and Sajeev John, Journal of Applied Phys. 113, 224501 (2013); doi: 10.1063/1.4809982. ABSTRACT  PDF
  89. "Resonant dipole-dipole interaction in confined and strong-coupling dielectric geometries", Ramy El-Ganainy and Sajeev John, New Journal of Physics, 15, 083033 (2013). ABSTRACT  PDF
  90. "Macroscopic response in active nonlinear photonic crystals", Gandhi Alagappan,Sajeev John, and Er Ping Li, Optics Letters 38, No. 18, 3514 (2013). ABSTRACT  PDF
  91. "Light trapping and near-unity solar absorption in a three-dimensional photonic-crystal", Ping Kuang, Alexei Deinega, Mei-Li Hsieh, Sajeev John and Shawn-Yu Lin, Optics Letters 38, No. 20, 4200 (2013). ABSTRACT  PDF
  92. "Synergistic plasmonic and photonic crystal lighttrapping: Architectures for optical upconversion in thin-film solar cells", Khai Q. Le and Sajeev John, Optics Express, 22, Issue S1, pp. A1-A12, DOI:10.1364/OE.22.0000A1 (2014). ABSTRACT  PDF
  93. "Near perfect solar absorption in ultra-thin-film GaAs photonic crystals", Sergey Eyderman, Alexei Deinega and Sajeev John, Journal of Materials Chemistry A, DOI: 10.1039/c3ta13655h (2014). ABSTRACT  PDF
  94. "Light trapping design for low band-gap polymer solar cells," Stephen Foster and Sajeev John, Optics Express, Vol. 22, Issue S2, pp. A465-A480 (2014). ABSTRACT  PDF
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