Presentation on theme: "Mikhail Rybin Euler School March-April 2004 Saint Petersburg State University, Ioffe Physico-Technical Institute Photonic Band Gap Structures."— Presentation transcript:
Mikhail Rybin Euler School March-April 2004 Saint Petersburg State University, Ioffe Physico-Technical Institute Photonic Band Gap Structures
Overview 1.Photonic crystals and photonic bandgap 2.Artificial opals 3.Photonic bandgap structure of artificial opals: Transmission experiments 4. 3D diffraction of light in opals: visualization of photonic band gap structure 5. Conclusions
Bragg Diffraction Wavelength does not correspond to the period Reflected waves are not in phase. Wave propagates through. Wavelength corresponds to the period. Reflected waves are in phase. Wave does not propagate inside.
Fabrication of artificial opals Silica spheres settle in close packed hexagonal layers There are 3 in-layer position A – red; B – blue; C –green; Layers could pack in fcc lattice: ABCABC or ACBACB hcp lattice: ABABAB
Diffraction on growth layers Energy of the gap in transmission and energy of the maximum in reflection spectra are coincided Transmission for different incident angles: 1.0 0 2.20 0 3.30 0 4.40 0 5.54 0
Band structure of diamond lattice Photonic band structure of diamond lattice (refractive index ~3.45) John et. al. PRE (1998)
Conclusions 1.Photonic band gap structures are new class of material possessed uncial photonic properties. Opal-based structures are 3D photonic crystals. 2. Photonic band gap structure was obtained for artificial opals in the visible range from angle-resolved transmission measurements. 3. Photonic band gap structure could be visualized by diffraction method. Diffraction patterns provides information about structure of photonic crystal.
Spontaneous Emission Control Emission is forbidden if energy of photonic bandgap and width of electron’s energy gap are coincided.