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We report polarized Raman spectra of single-wall carbon nanotubes (SWCNs) dispersed in one-dimensional channels of an AlPO4-5 (AFI) single crystal. From the polarization dependence of the Raman intensity, three main Raman bands near 1600cm−1are identified, respectively, to be A1g, E1g, and E2gRaman-active modes. In the low frequency region, the radial breathing mode with A1gsymmetry is observed at 530cm−1. The A1gbreathing mode of the SWCNs in the AFI channels is shifted to a higher frequency because of the interaction between the nanotubes and the rigid channel walls of the AFI crystal.

We report room-temperature measurements of optical gain and gain spectra of ultraviolet emission from ZnO thin film. An optical gain of 300 cm is measured at a fluence of 3.8 μJ/cm. The large gain is attributed to the modification of the spontaneous emission rate by the dielectric photonic structure of these films. The presence of excitonic gain is also observed in the room-temperature gain spectra.

Optical properties are studied for Se species accommodated in channels of an AlPO4–5 single crystal. Polarized Raman spectra show that the Se species is of helical chain structure with D3symmetry. The optical phonon modes of the Se chains are shifted towards higher frequencies from that of the trigonal Se crystal, because of the loss of inter-chain interactions in Se/AlPO4–5. High anisotropic absorption spectra have been observed for the Se chains. The lowest excitation energies are shifted towards high energy about 0.6 eV from the band edge transitions of the trigonal Se crystal. The blue shift is attributed to the quantum confinement of carriers in a Se chain with diameter 7.3 Å.

High quality ZnO thin film was grown by Laser MBE. A pure ceramic ZnO target was ablated by the KrF laser pulses (248 nm, 10 Hz, 1 J/cm²) in an ultra high vacuum to deposit ZnO film on sapphire (0001) substrate. The lateral grain size was about 50 nm for the sample with thickness of 55 nm. At room temperature, the peak of the exciton absorption and the photoluminescence have the same energy. Under high density excitation (355 nm, 35 ps, 10 Hz), an exciton–exciton collision process was observed as P2 and P lines where 2S exciton and ionized exciton remain. From the edge of the sample, a very rapid increase of the P line was observed with the increase of the excitation power. A fine structure that comes from the cavity mode was also observed. These facts suggest that the lasing of the exciton was observed at room temperature.

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The nonradiative damping factor (Γ) of quantized 1s-excitons in ultrathin CuCl films is found to be proportional ton/L2(L: film thickness;n: exciton's quantum number). This behavior of Γ can be explained in terms of the exciton-acoustic phonon interaction via deformation potential in the confined exciton system.