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Photorefractive Effect in an Imperfect Cerium Doped Barium Titanate Crystal: Reflection Grating Case
(2026-01-01)
Khotphuthon, Wasuphon
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Plaipichit, Suwan
;
Suchat, Suebtarkul
;
Buranasiri, Prathan
The photorefractive (PR) effect, a nonlinear optic phenomenon, occurs in materials that have electro-optic (EO) properties. When two coherent beams of light interfere with each other in a PR material, donor electrons between valence band and conduction band, caused by material impurity, absorb the photon and are excited into the conduction band and generate electron-hole pairs. This process induces a periodic electric field called a space charge field that alters the material’s refractive index due to the EO effect. In this research, we explored reflection grating (RG) in an imperfect Ce-doped BaTiO3 crystal and then showed optical image correlation using the RG. Two beam coupling was investigated using two non-Gaussian incident beams on the opposite surface of an imperfect Ce-doped BaTiO3 crystal. Light at green wavelengths from a semiconductor laser was used as the source of the incident beams and entered at certain angles relative to the crystal c-axis. Large beam coupling power was observed in both incident directions when the angle between both incident beams is at Bragg’s angle in the direction of the c-axis. The diffraction light was found to be in the same polarization as the incident beam. In addition, interesting results for the optical correlation using reflection grating were demonstrated. These results suggest that by doping BaTiO3 with cerium, strong beam coupling or photorefractive grating can be observed with certain incident writing angles on the crystal, which could be utilized in future flexible holographic devices in the future.
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Optimizing indoor digital holography for photovoltaic surface analysis: A novel approach for solar PV testing conditions
(2025-01-01)
Bako, Abdullahi
;
Voochaiphum, Bunyarit
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Suchat, Suebtarkul
;
Buranasiri, Prathan
The sun is a clean, inexhaustible, free energy source, and it is environmentally safe. The rapid expansion of the solar photovoltaic (PV) industry demands innovative quality control techniques for defect detection and efficiency optimization of solar cells. Traditional methods such as electroluminescence, photoluminescence, and infrared thermography have limitations in detection resolution, real-time monitoring, and surface characterization. In this research, a novel approach digital holography-based non-contact method for detecting and analyzing defects in solar cells, such as micro-structural defects, surface roughness, dust, scratch, and cracks, was investigated. Laser module was used as our light source to optimize indoor test conditions. An integrated recognition system was developed to automate and improve accuracy using real hologram images. Reconstruction images and Fourier transforms were used to extract the phase and amplitude across the solar PV cell. This preserved the module's integrity and providing detailed defect information from the solar surface.
2
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Entangled photon recovery state using a fiber ring resonator incorporating an erbium-doped fiber amplifier
(2008-12-01)
Suchat, Suebtarkul
;
Khunnam, Wanchai
;
Yupapin, Preecha P.
We investigate a new system of photon-entangled recovery states using a fiber ring resonator incorporating an erbium-doped fiber (EDF). We also show that states of weak entangled photons can be regenerated and recovered after circulating in the amplified fiber optic medium. The output entangled photon states can be regenerated by adjusting the polarization controller of the amplified photons. Results obtained show that such a proposed system can be used to perform the polarization entangled recovery states, and the amplified output gain can be achieved. The amplifying noise is also detected and seen on the spectrum output, which affects the entangled photon output visibility. The change in the system temperature is also investigated, which shows that entangled state walk-off compensation is required to obtain the optimum entangled photon visibility. © 2008 Society of Photo-Optical Instrumentation Engineers.
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The entangled photons generation system using week light in fiber optic and timing-walk off compensation
(2007-01-01)
Yupapin, Preecha P.
;
Khunnam, Wanchai
;
Suchat, Suebtarkul
We propose a new system for multi-entangled photons generation using an all fiber optic arrangement. The generation of the entangled states of two, four and eight entangled photons using an all fiber optic scheme is analyzed. The timing-walk off on the entangled state of two and four entangled photons suffering from the polarization in fiber optic is characterized. The compensation of such effects and the optimal entangled states of the entangled photons in fiber optic are analyzed and discussed. © 2007 World Scientific Publishing Company.
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Entangled photon generation using a fiber optic Mach-Zehnder interferometer incorporating the nonlinear effect in a fiber ring resonator
(2007-01-01)
Yupapin, Preecha P.
;
Suchat, Suebtarkul
A new system for entangled photon-pair generation using an all-fiber optic scheme consists of a fiber optic Mach-Zehnder interferometer (MZI) incorporating a fiber optic ring resonator. The Kerr nonlinearity effect in the fiber ring resonator is exploited for the generation of two independent squeezed beams. The advantage of such a system is that it requires a simple arrangement without any optical pumping parts or bulky optical components. Polarized light pulse trains are launched randomly into a MZI, and one part of the light is delayed in the longer path. The output pulses from both arms of the MZI enter a fiber optic ring resonator. A polarization controller controls the polarization states of the light pulses while they circulate in the ring resonator. The superposition of the nonlinear light pulses in a fiber optic ring resonator randomly occur. These forms are seen on an avalanche photodetector. The results are in good agreement with previous work. © 2007 Society of Photo-Optical Instrumentation Engineers.

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