| Research Abstract |
We Succeeded for the first time in fabricating Such a 2D photonic crystal with the lattice constant on the order of 1mum as having a common 2D photonic band gap for H-polarization. We have revealed experimentally the unique optical properties Which include the existence of the uncoupled modes that can not couple to the external plane wave, anomalous excitation-wavelength-dependent spectra of 0-th-to-3rd order Bragg reflected intensities that are another manifestation of physical property of the respective photonic bands, and emission spectra from a small amount of molecules placed in a 2D photonic lattice that reflect also the density of the present photon states.
We found new mirror-less laser actions characteristic of a 2D photonic crystal. By optically-pumping a 2D photonic-lattice specimen with the air-holes filled with a dye-solution, we observed the laser action at two specific wavelengths, i.e., one around the peak of the spontaneous emission spectrum and the other at a longer wavelength. The respective mechanisms are elucidated as being caused by a high Q-value of an uncoupled eigen-mode and a slow group velocity at a specific wavelength resulting in a long effective interaction length with the help of a small amount of feedback at the interfaces.
Next, on the basis of a simulation experiment in the far-infrared region we have found that a simple cubic lattice made of a high dielectric constant should have a full band gap, which is most attractive for developing such a 3D photonic lattice at visible wavelengths.
We have also developed theoretical woks with a lots of outcomes. Namely, we have assigned the respective eigen-modes the group theoretical symmetry in a few typical 2D and 3D photonic lattices, including identification of the uncoupled mode, constructed a general theory on the basis of Green function for optical response of the photonic crystal, and also developed a new method for exploring defect modes.
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