الفهرس 
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Abstract
It is interesting to note in recent years there are a large number of studies and applications for the topic of photonic crystals (PCs) because of their new and useful properties. In addition, there are many advantages to photonic crystals materials as high reflectance materials as well as high transmittance materials based on the target application.
In this thesis, the optical characteristics for the proposed photonic crystal Aluminum oxide and titanium oxide (Al2O3/TiO2) composite were studied in one dimension and two dimensions, which shows a high reflectivity (” ” ” " ~ " ” ” ” 99 %) for a wide wavelengths range (400-600 nm)at different angles (50°–89°). The chosen photonic crystal composite can be useful for some applications, for instance, intensifying the Cherenkov radiation. where it is used in our study to reflect the Cherenkov light many times (to be intensified) which comes out using radioisotope 90Sr-90Y. The output intensified light has power 1.45 μ W and 1.45 nW for 90Sr-90Y with the activity 1Ci and 1mCi respectively, which can be used for micro/nano-power source applications.
In addition, a new type of photonic crystal (PC) was designed as a transmitter. The transmittance spectra of the one-dimensional (1D) photonic crystal silicon dioxide/magnesium fluoride (SiO2/MgF2) were simulated for different incident angles, and the results showed a high transmittance (99.5 %) in the wavelength range of (400–600 nm). Simulations of two-dimensional (2D) photonic crystals were studied, and the transmittance values were investigated. The high transmittance of the SiO2/MgF2 PC allows Cherenkov light to pass without losing its initial incident intensity, which is utilized in a wide range of applications like improving the counting efficiency of the Cherenkov counter. Due to the high transmittance of SiO2/MgF2 photonic crystal compared to traditional polyethylene (generally used to fabricate the walls of the counter vial), the counting efficiency of the Cherenkov counter will be increased by 15% and 9.5% for 1D and 2D respectively.
In chapter 1, we introduce the basic concepts of Cherenkov radiation and photonic crystals. In chapter 2, we present the production of intensified blue light by Cherenkov radiations phenomena and improve the efficiency of the counter. In chapter 3, we show the theoretical calculation by using TMM to investigate the optical properties of photonic crystals. In chapter 4, we illustrate our results and discussion. In chapter 5, we summarize the outlines of our experimental and theoretical work.