The interaction of self-assembled InxGa1-xAs quantum dots with nondegenerate modes of a two-dimensional photonic-crystal defect microcavity has been investigated in the weak-coupling regime. Photoluminescence intensity measurements show a transition from a pump rate limited regime at low excitation to cavity-controlled modes at high excitation. We observe considerably different saturation levels for quantum dots on and off the defect resonance. An enhancement of light emission by a factor of 9 due to the Purcell effect is obtained from this saturation behavior. Using the different temperature shifts of the quantum dot emission lines and the cavity mode, individual dots are tuned in and out of resonance, thus controlling their spontaneous emission rate.

The Raman spectra of C70 Single crystals have been measured at pressures up to 17 GPa. The frequency Omega of most of the optical intramolecular phonons increases linearly with pressure P. The slope of the pressure shift d Omega/dP itself has jumps at 2+/-0.2 and 5.5+/-0.5 GPa. These jumps are correlated with a sharp change in the half-width of the Raman line for several optical modes. The peculiarities of the Raman scattering are linked with phase transitions caused by an orientational ordering of the C70 molecules in the crystal lattice as the pressure is raised.

The Raman spectra of C70 crystals have been studied at pressures up to 17 GPa. The frequency OMEGA of most of the optical vibrations increases linearly with the pressure P. The pressure-induced shift partial-derivative OMEGA/partial-derivative P itself has jumps at P1 congruent-to 2+/-0.2 and P2 congruent-to 5.5+/-0.5 GPa. The jumps observed in partial-derivative OMEGA/partial-derivative P are correlated with a sharp change in the half-width of the Raman line for several optical modes. These spectral features of the Raman scattering are linked with phase transitions caused by an orientational ordering of the C70 molecules in the crystal lattice as the pressure is raised.