In this paper, optical phase conjugate beam with the using of different resonator configurations has been investigate. Two types of SPPC resonators were selected to use, the first one is linear resonators formed by crystal surface and the other one is linear resonators formed by single mirror and a photorefractive crystal. In our experiment, cerium doped barium titanate crystal (BaTiO<sub>3</sub> : Ce) and He-Ne laser with wavelength of 632.8 nm have been used. From the results of both cases, the angle of the incident beams is optimum at 37.95° respect to the normal line of the surface that parallel to the c-axis of the crystal. The generating time of OPC beam are 150 seconds and 330 seconds for the first and second type resonators, respectively. The reflection ratios are equal to 8.75% and 5% for the first and second type resonators, respectively (the first type resonators could provide better reflection ratio).
In this paper, we have solved nonlinear coupled-mode equations valid for light propagation in a one-dimensional photonic crystal by using numerical expression. Moreover, the medium in this problem has been considered as a nonlinear <i>x</i> <sup>(3)</sup> material. The numerical results have been used to calculate the conversion efficiency in nondepleted-pump limit. The results have been shown us that the maximum conversion efficiency of third-harmonic generation could be occurred when the fundamental field has been tuned near the lower band-edge of photonic band-gap that band-edge phase matched condition has been satisfied.
The sample of CuFeO<sub>2</sub> delafossite was synthesized by solid state reaction for studying alcohol gas sensing properties. The Seebeck coefficient and electrical conductivity were measured in the high temperature ranging from 300 to 960 K. The CuFeO<sub>2</sub> gas sensing displays high sensitive to ethyl alcohol gas in sensitivity ranging from 70 to 93 % and responding in 2 to 4 minute. The electronic characterization on the sample exhibits p-type conductor and displays electrical conductivity ranging from 3 to 13 S/cm with activation energy in 49 meV. This study suggests that CuFeO<sub>2</sub> delafossite is a new one to be candidate in oxide material for alcohol gas sensing.
The CuCoO<sub>2</sub> sample has been synthesized by a conventional solid-state reaction method to investigate electronic transport and optical properties for <i>p</i>-type transparent conducting oxide materials. The crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature. The UV-VIS-NIR and FTIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient sign confirms the samples displays the p-type conducting. The electronic transport energy for activating free carrier production and conduction contain 0.276 eV and 0.131 eV, respectively. The optical direct gap is 3.65 eV which is a visible-transparent oxide material. These results support that the CuCoO<sub>2</sub> oxide compound is p-type transparent conducting oxide materials.
In this paper, we have proposed the novel prototype of the portable fingerprint scanner. Using this method, the low coherence digital holography technique has been used to verify fingerprints. In our experiment, the Michelson’s interferometer has been setup first for determining the coherence length of a laser diode with wave length of 635 nm. In our model, the light transmission and reflection properties of the glass slide have been applied. Then, the glass slide has been used as a beam splitter for separating the light to two beams, which are the reference beam and fingerprint image bearing beam. The results show fingerprint pattern, which are reconstructed with numerical method.