We observed stable photoluminescence from close-packed cubic SiC nanocrystals that are self-assembled into thin solid film. The peak wavelength shifts from blue to near UV with increasing excitation energy and follows well the quantum-confinement effect. The photoluminescence excitation spectrum indicates a 3.47 eV bandgap corresponding to a particle size of 2.3 nm. The nanocrystal film shows triple-exponential photoluminescence decay with lifetimes of 2.3, 8.5, and 36.9 ns. The results open the possibility of the solid state UV-blue light emitting by use of the SiC nanocrystals in photonics and photonics/electronics integration.

We observe multiple simultaneous cascaded-v (2) Č erenkov conical radiations in radially poled nonlinear photonic crystals. By using two incident fundamental waves x 1 and x 2 , a variety of cascaded nonlinear up-conversion processes occur which result in high-frequency Č erenkov radiations at 2x i þ x j ði; j ¼ 1; 2Þ exhibiting as multicolor conical beams. Two types of phase-matching geometries with different emission angles are demonstrated for each kind of cascaded-v (2) Č erenkov radiation. The external angle of the Č erenkov radiation exhibits strong dependence on the fundamental wavelengths. The experimental results agree well with the theoretical calculations.