Threshold amplitude gain at the calculated lasing modes for symmetric and asymmetric PCs with 37 and 53 gain lattice points, respectively. The rod arrays for these PCs are shown by circles in Figs. 4 and 5. The inset shows the photonic band structure for the light field with the TE mode (The electric field is parallel to the rods). In this figure, and values are normalized in units of and , respectively, where is the period of the lattice. Modes selected for the later investigation are denoted as S1, S2, and S3 for a symmetric PC and A1, A2, and A3 for an asymmetric PC.
Light intensity spectra in reciprocal space ( space) for (a) mode S1, (b) mode S2, and (c) mode S3 in a symmetric close-to-lasing PC. Intensity increases in the order white, gray, and black. The hexagon in this figure indicates the first Brillouin Zone of this lattice. The circle indicates the position of the intensity for the waves elastically scattered by this PC.
Variations of light intensity spectra in reciprocal space ( space) with the variation in the amplitude gain assumed in the asymmetric PC. Spectra variations are drawn for two incident angles (0° and 90°) of the excitation light wave. Here, the assumed amplitude gain ranges from no gain, through one half of the threshold, to the close-to-lasing value. The hexagon and the circle are the same as described for Fig. 2.
Poynting vector (light-energy flow) distributions in real space for (a) mode S1, (b) mode S2, and (c) mode S3 in the symmetric close-to-lasing PC. The amplitudes of the Poynting vectors are shown by the contours (the intensity increases in the order white, gray, and black) and the vector directions are shown by the small arrows. The rod array is displayed as circles.
Poynting vector (light-energy flow) distributions in real space for (a) mode A1, (b) mode A2, and (c) mode A3 in the asymmetric close-to-lasing PC. See the caption of Fig. 4 for a description of the details.
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