• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.160-163
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• 2002

Silica waveguide for an integrated diffractive optical head system was designed and fabricated. The waveguide was designed to optimize the optical efficiency of red and/or blue laser source, and a lab-made RF magnetron sputter was adopted to deposit silica cladding and core layers on SiO$_2$/Si substrates. The cladding and core layers were formed using commercial targets, and the former was done with ＃7740 and the latter with BK7 and BAK4, respectively The surface roughness of the waveguide layers was measured to be 30.3${\AA}$ for BK7 and 17.8${\AA}$ for BAK4, and the difference of refractive indices between core and cladding layers was 0.9% and 2.5%, respectively. The waveguide fabricated with the core layer of BK7 showed better optical properties when the final diffractive optical probe heads were measured with red laser(650nm) source.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.9
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• pp.760-765
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• 2009

The effects of $Fe_2O_3$ addition on optical and electrical properties of MgO films as a protective layer for AC plasma display panels were investigated. Doped MgO films prepared by the e-beam evaporation have a higher ${\gamma}$ (secondary electron emission coefficient) than pure MgO protective layer. Roughness increased with amount of $Fe_2O_3$ up to 100 ppm and then decreased further addition. These results showed that discharge properties and optical properties of MgO protective layers seemed to be closely related with microstructure factors such as roughness. Good optical and electrical properties of ${\gamma}$ of 0.120, surface roughness of 14.1 nm and optical transmittance of 94.55% were obtained for the MgO + 100 ppm $Fe_2O_3$ protective layer sintered at $1700^{\circ}C$ for 5 hrs.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.152-156
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• 2004

We have studied the effective optical absorption power of Si solar cell with $SiO_2$-antireflection layer based on a mathematical modelling of AM(air mass)1 spectrum and Si refractive index in the wavelength range(0.4 $\mu\textrm{m}\leq$λ$\leq$$0.97\mu\textrm{m}$). The effective optical absorption power obtained from the theoretical calculation was 450 and 520 W/$\m^2$ for the Si solar cells with $SiO_2$-antireflection layer of 500$\AA$ and 1000$\AA$, respectively. The optimum thickness of $SiO_2$-antireflection layer showing the minimum reflection loss was about 1000$\AA$ in the computer simulation. Two kinds of Si solar cells named EBS(500$\AA$) and EBS(l000$\AA$) were fabricated to evaluate the effect of $SiO_2$-antireflection layer thickness on the optical absorption. The epitaxial base Si cell with $SiO_2$-antireflection layer of 1000$\AA$ [EBS(l000$\AA$)] showed the output power improvement of about 15% upon the EBS(500$\AA$) cell due to larger absorption of effective optical power under illumination of AM1, 1 sun.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.620-625
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• 2007

The effects of $Gd_2O_3$ addition and sintering condition on optical and electrical properties of MgO films as a protective layer for AC plasma display panels were investigated. Doped MgO films prepared by the e-beam evaporation have a higher ${\Upsilon}$ (secondary electron emission coefficient) than pure MgO protective layer. Relative density and grain size increased with amount of $Gd_2O_3$ up to 100 ppm and then decreased further addition. These results showed that discharge properties and optical properties of MgO protective layers seemed to be closely related with microstructure factors such as relative density and grain size. Good optical and electrical properties of ${\Upsilon}$ of 0.138, surface roughness of 5.77 nm and optical transmittance of 95.76 % were obtained for the MgO+100 ppm $Gd_2O_3$ protective layer sintered at $1700^{\circ}C$ for 5 hrs.

• Journal of the Optical Society of Korea
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• v.17 no.1
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• pp.33-37
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• 2013

In this study a new design concept of the Fabry-Perot filter, constructed with an anisotropic space layer and a couple of isotropic mirrors, was proposed based on the Maxwell equations and the characteristic matrix method. The single- and double-cavity Fabry-Perot filters were designed, and their optical properties were investigated with a developed software package. In addition, the dependence of the transmittance and phase shift for two orthogonal polarization states on the column angle of the anisotropic space layer and the incidence angle were discussed. We demonstrated that the polarization state of electromagnetic waves and phase shifts can be modulated by exploiting an anisotropic space layer in a polarization F-P filter. Birefringence of the anisotropic space layer provided a sophisticated phase modulation with varied incidence angles over a broad range, resulting in a wide-angle phase shift. This new concept would be useful for designing optical components with isotropic and anisotropic materials.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.23-28
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• 1991

A single-layer neural network with 4$\times$4 input neurons and 4 output neurons is optically implemented. Holographic lenslet arrays are used for the e optical interconnection topology, a liquid crystal light valve(LCLV) is used for controlling optical interconection weights. Using a Perceptron learning rule, it classifics input patterns into 4 different categories. It is shown that the performance of the adaptive neural network depends on the learning rate, the correlation of input patterns, and the nonlinear characteristic properties of the liquid crystal light valve.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.94-95
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• 2002

Photonic crystal (PC) has special interests for their promising applications in three-dimensional photon control and integrated devices. In a nonlinear photonic crystal (NPC), optical intensity in a defect layer is greatly increased due to the location function of NPC and nonlinearity. The nonliearity of the defect layer is very much enhanced because the group velocity is reduced and the interaction time between light and nonlinear medium in the defect layer is enlarged. (omitted)

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.432-437
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• 2001

It is necessary to improve mechanical and optical porperties in the optical disk substrates as the information storage devices with high storage density using blue laser are being developed. Injection compression molding is regarded as the most suitable process to manufacture optical disk substrates for quality recording and read-out. In the present research, the effects of processing conditions and the insulation layer thickness on gapwise birefringence and the land-groove pattern were investigated. It was found that the values of the birefringence distribution were very sensitive to mold temperature history, and the level of birefringence reduced and, furthermore, the quality of replication was improved due to the insulation layer.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.111-114
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• 2004

Using the embedded optical fiber sensor of totally-reflected extrinsic Fabry-Perot interferometer(TR-EFPI), longitudinal strains(Ex) of the core and skin layers in glass fiber reinforced plastic(GFRP) cross-ply composite laminates have been measured. Transmission optical microscopy was employed to study the damage formation around the TR-EFPI sensor. It was observed that values of ex in the interior of the skin layer and the core layer measured by embedded TR-EFPI sensor was significantly higher than that of the specimen surface measured by strain gauges. The experimental results agreed well with those from finite element analysis on the basis of uniform stress model. Large strains in the core layer led to the occurrence of transverse cracks which drastically reduced the strain at failure of optical fiber sensor embedded in the core layer.

• Current Optics and Photonics
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• v.5 no.1
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• pp.1-7
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• 2021

For higher sensitivity in ultraviolet (UV) and even vacuum ultraviolet (VUV) detection of silicon-based sensors, a sandwich-structured film sensor based on Ag Localized Surface Plasmon Resonance (LSPR) was designed and fabricated. This film sensor was composed of a Ag nanoparticles (NPs) layer, SiO2 buffer and fluorescence layer by physical vapour deposition and thermal annealing. By tuning the annealing temperature and adding the SiO2 layer, the resonance absorption wavelength of Ag NPs matched with the emission wavelength of the fluorescence layer. Due to the strong plasmon resonance coupling and electromagnetic field formed on the surface of Ag NPs, the radiative recombination rate of the luminescent materials and the number of fluorescent molecules in the excited state increased. Therefore, the fluorescent emission intensity of the sandwich-structured film sensor was 1.10-1.58 times at 120-200 nm and 2.17-2.93 times at 240-360 nm that of the single-layer film sensor. A feasible method is provided for improving the detection performance of UV and VUV detectors.