The Fabrication And Research Of Photorefractive Micro-structure

Photorefractive microstructure material which is made by using photorefractive effect is a kind of photonic crystal. Its space measure is on the level of the wavelength of light-wave. The most remarkable character of the photonic crystal is that it possesses the photonic gap. The waves whose frequency is within the pale of the extent of the photonic gap are forbidden to transmit through the photonic crystal. To some extent, the applied value of the photonic crystal depends on the existence of the state of defect. A defect can be made though destroying the structure of the periodical lattice. Photons whose frequency were equal with the one of the defect can be localized or transmit along it. The intensity of the light-wave would attenuate rapidly when they depart from the location of the defect. We can make a transparent window for electromagnetic wave within a certain extent. It is possible to apply that kind of window to guide the electromagnetic wave.At the present time, inducing the photonic lattice by light-wave is the best method of all simple, convenient and low-cost one to investigate the band-gap and band structure. The point-defect and linear-defect were constructed respectively by taking off a point and a list of points in the array of the LiNbO₃: Fe crystal. Thereby, it has played an important role in the development and application of the microstructure optics that investigating the state of defect and band-structure in the LiNbO₃: Fe crystal.In this paper, firstly, we investigated that how to construct the defect in the photorefractive photonic lattice. Secondly, the phenomenon that the light-waves were localized by the defect was studied. Lastly, we make researches on the interaction between beam of light and crystal lattice. The work I have accomplished mostly as follows:1. The thickness of the photonic crystal, refractive index, the focus of the lens, the distance of the subject and the aperture of the lens played a crucial role in the quality of the reading-in lattice when we constructed the defect in the LiNbO₃: Fe crystal with different thickness. Under the circumstances, the condition of the experiments were certain, the measure of the lattice had a lower limit. We analyzed the relationships theoretically between the condition of experiments and the quality of the lattice. The same analysis was made between the measure of the lattice and the quality of it. Base on optimizing the experimental factors, an optics resonance micro-cavity was made which the wave-guide space between was 40 micron by using that method.2. Photonic lattice of linear refractive index hollow and linear defect were induced by using the method of imaging in the LiNbO₃: Fe crystal. The light-wave can be localized by the defect when we use detecting beam of light, while hallow did not have this characteristic. According to the theory of the band gap, we explain the phenomenon. In our opinion, the reason why was the light-wave localized by the defect is that the light-wave was reflected by the wave-guide array time and again. The type of the wave-guide mechanism is Bragg reflection.3. The facular of the array element in the three-beam of light interference lattice split to three when the triangle photonic crystal lattice was conducting by the three-beam of light interference light field in LiNbO₃:Fe crystal. The theory of the phase split was applied to analyze the phenomenon. The result of the numerical simulation accorded with the experimental phenomenon well. Both of them show that the interaction between light-wave and crystal lattice will lead the phase split, secondary spatial harmonic wave and advanced spatial harmonic wave。The phenomenon was not only found in simple structure of the photonic crystal, but also did in the complicated one.