Modification of spontaneous emission in photonic crystals

1999 ii The dissertation of Mikhail Boroditsky is approved. Figure 1. (a) A small section of an infinite dielectric slab with a triangular array of through holes resting on a glass substrate; (b) Unit cell used for the computation of the frequency ν vs. wave-vector k dispersion relationship. Figure 2. Dispersion diagram of TE-like modes of the infinite photonic crystal shown in Fig. 1(a). Figure 3. Four different cavity configurations in the finite size photonic crystal that were analyzed: (a) A defect is introduced by adding extra material to the bridge between two holes; (b) A defect is introduced in the spot between three holes; (c) The defect consists of added material in the center of a hole; (d) A dielectric cylinder resting on a glass slab (for comparison). Figure 4. Evolution of the localized mode frequency, effective volume and cavity Q for the defect placed on the bridge between two holes: (a) Resonant frequency of the mode; (b) Effective mode volume in units of (λ/2n) 3 ; (c) Cavity Q-factor Figure 5. Same as Fig. 4 for the defect placed between three holes. Figure 6. Evolution of the localized mode frequency, effective volume and cavity Q for the defect placed on the center of a hole: (a) Resonant frequency of the mode; (b) Effective mode volume in units of (λ/2n) 3 ; (c) Cavity Q-factor. Figure 7. Mode pattern of resonant modes, in the plane of the structure, for the modes with the smallest effective mode volume. 16 17 20 21 22 24 25 v Figure 8. Experimental setup for photoluminescence measurements. The absolute external quantum efficiency is measured by calibrating the measured photoluminescence from the sample aginst the reading measured from the laser scattered off a perfect white Lambertian reflector. Figure 9a. The semicinductor structure corresponding to the radiative transport model consists of a thin semiconductor film sitting on a sapphire substrate. Figure 9b. The schematics of the AlGaN/InGaN MQW structure grown by MOCVD on a C-plane sapphire substrate. Figure 10. a) The InGaAlP sample consists of 0.7µm thick In 0.5 (Ga 0.92 Al 0.08) 0.5 P (λ=630nm) active region doped at n=10 17 cm-3 level sandwiched between n-type InAlP cladding layers grown on absorbing GaAs substrate.b) When the top InAlP cladding layer is etched away, the nonradiative surface recombination on the exposed surface of the active region becomes the dominant recombination process. Figure 11. a) An n-type …