In this report, we present three-dimensional photonic crystals fabricated by a four-beam holographic lithography method using visible photoinduced polymerization. High-quality face-centered-cubic single crystals with a large range of polymeric matrix volume fraction were fabricated using optimal conditions obtained from computer simulations. Optical measurements of the crystals showing photonic band-gap-like behavior are presented for different polymeric matrix volume fractions.

The magnitude and spectral response of second-harmonic generation ͑SHG͒ from 0.4 nm single-walled carbon nanotubes ͑CNTs͒ in the channels of AlPO 4 -5 zeolite is reported. The second harmonics ͑SH͒ was found to be polarized perpendicular to the tube axis and maximized by an excitation polarization at 45°to the tube axis. A SH resonance peak at 2 eV was observed, which corresponds to the lowest-energy excitonic state in chiral ͑4,2͒ CNTs. The second-order optical susceptibility ͑2͒ of the system was determined to be 10 −6 esu, which agrees with the large ͑2͒ predicted for small diameter CNTs. These experimental results suggest that SHG can be used to characterize the symmetry and chirality of CNTs.

In this letter, we report a diamondlike structure. Our theoretical analysis reveals that a large complete band gap exists between the second and third bands with only a very low refractive index is needed (n⩾2.05) to open the complete band gap for this inverse structure. Large-scale and high-quality three-dimensional structures with this diamondlike symmetry are fabricated by a holographic lithography method using four laser beams incident from the same half-space. The beam geometry is similar to that for the face-centered cubic (fcc) structure except that the central beam is circularly polarized and the polarizations of the three outer beams must be optimized, which is critical to construct this diamondlike interference pattern.

We perform a kind of computer stimulation on the multi-laser-beam interference. Using this method, we picture the interference patterns and describe the influence of the polarization of lights upon the clarity of the pattern. We find out the relations between the polarization states of the lights for the case of the best pattern and provide an optimal solution of the polarization on holographic lithography technology, and experiential formulas. This kind of analysis will improve the fabrication of submicrometer periodic structure efficiently.