Results

Through our visualisation we were able to observe the way the photonic modal pattern changed with variations of wavelength and put this in relation to a position on the partial band diagram. To view the animations please go to http://www.vislab.usyd.edu.au/sc3/jean and use an SGI machine as the movies are in movie format and not quicktime or MPEG's.

In the Figure below the hexagonal circle structure is shown overlayed on top of the waveform throughout the pattern. The intensity of the pattern increases with decreasing wavelength and this first image is in the lower band at high wavelengths where the intensity is quite small. This animation is autoscaling and hence all the frames are on the same scale giving a good physical interpretation of the relative intensities of the electric field. This animation was done in AVS express by my partner Tim as AVS has many advanced functions which are not available in avs such as the f2dcircle module which allows circles to be simply overlayed on top of an image.

The other animation separates the real and imaginary parts of the wave as the wavelength changes. This animation was made in avs using the extract scalar modules and field math to separate the real and imaginary parts and find the modulus of the data. The central image is the modulus of the real and imaginary parts and is a physical representation of how the waveforms change. You may notice that the imaginary part changes suddenly when it reaches the a band gap. This is quite good as it gives a very clear indication of where the band gap starts and finishes. In the band gap the wave stops propagating and becomes a standing wave which is totally reflected from the solid. This animation has a different scaling procedure , each frame has its own scale so that it is possible to see small perturbations in the waveform at low intensity ends of the band diagram which would otherwise not be seen. Also, in the lower band shown below, the waveform is centred on the circles and at the end of the trip along the band the wave minima occur imbetween the circles.

The Band Gap

By observing each of the generated datasets we were able to look at the waves behavious is it pass through the band gap. In the band gap where the wave stops propagating The wave stops propagating as its imaginary part has very low intensities which are arranged in a complex pattern. The reason why there is still some imaginary component even in the band gap suggests that the seamouse doesn't have a prefect band gap which mans that the hair structure is not perfectly symmetrical I in all directions hence a very small propagating component wave remains. Images from the Band Gap are shown below.

The Upper Band

In the upper band the intensities have increased and the minima are now occur imbetween the circles of the seamouse structure.

The figure below is quite interesting because it shows the point where the modal pattern we were plotting becomes very complicated. As soon as the wavelength passes the region where the yellow line first occurs on the band diagram the resulting modal pattern seems to be affected by interference from these close neighbouring bands.

Towards the end of the upper band each mesh becomes increasingly complicated, the other bands which are running in the same x-plane appear to be interfering with the state and creating some very complex, although pretty waveforms. Some of the mysteriously complex waveforms at the end of the upper band are shown below.