• Journal of the Korean Chemical Society
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• v.23 no.5
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• pp.314-319
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• 1979

The electronic spectrum of marine dinoflagellate antenna pigment, peridinin, has been described in terms of PPP SCF MO CI computations and fluorescence polarization of the peridinin component in photosynthetic pigment complex of Amphidinium carterae. The main absorption band at 470 nm, $^1B{\leftarrow}A$, is polarized nearly along the long molecular axis. There appear to be two ${\pi}{\rightarrow}{\pi}^*$ transitions (C and $D{\leftarrow}A$) in the socalled "cis" peak region, and they are polarized roughly parallel to the main $B{\leftarrow}A$ absorption. In addition, we have found that the carbonyl group undergoes very 1ittle reorganization of the electronic structure in going from the ground to the $^1B$ excited states of peridinin, while the allenic group shows a strong charge transfer tendency in producing an electron-deficient allente allene group in the excited state.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.7-13
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• 2009

By incorporating a polarization beam splitter and fiber coupler, we propose a fiber-optic multiwavelength-switchable interleaving filter that can function as a polarizaiton-independent transmission or reflection-type one. The proposed filter consists of a polarizaiton beam splitter and a Sagnac birefringence loop that is composed of a 50:50 coupler, polarizaiton-maintaining fibers, and two quarter-wave plates. In the proposed filter, a transmission-type filter with a channel isolation > 18[dB] or a reflection-type one with a channel isolation ~3[dB], whose channel spacing and switching displacement were 0.8 and 0.4[nm] in common, respectively, could be obtained. Channel interleaving operation could be performed by the proper control of waveplates within the Sagnac birefringence loop.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.271-276
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• 2006

In this paper a polarimetric airborne SAR measurement has been used to study the radar polarimetric characteristics in the intertidal area on the south coastof the Korea. The L-band NASA/JPL airborne SAR (AIRSAR) data, which were acquired on the intertidal zone during PACRIM-II Korea campaign on September 30, 2000, were used for this research. The most intertidal zones of Yeoja Bay are composed of muddy soils with high silt and clay percentage. Models of microwave scattering from rough surfaces, i.e., semi-empirical model, and Extended Bragg model, were applied to investigate the surface characteristics of intertidal zones.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.661-667
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• 2008

In this study, cholesteric liquid crystal (CLC) was synthesized and applied as a polarizing component on the optical film of back light units (BLU) for LCDs. After mixing CLC with nematic liquid crystal, this mixture was fulfilled in the module consisting of two films and then its amplifying efficiency and polarizing ability for a planarly emitted light were examined to apply as a BLU polarizer film for increasing the brightness of light. The properties of CLC compound were tested by UV/Visible spectroscopy and polarizing optical microscopy (POM). Flexible spacer was made by linear carboxylic acid group of cholesteric derivatives between cholesterol mesogen units for one-axis orientation in each layer. The CLC containing film could be used as a module to increase the ability of polarization and to enhance brightness of BLU and to widen wavelength range by stacking the films.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.560-567
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• 2011

In this paper, we reduced the optical noise interference using polarizers in a visible light communication system. In a transmitter, two light-emitting diodes(LEDs) are modulated synchronously by the original and the reversed signals of the transmitted data, and the two LED lights are radiated through orthogonal polarizers. In a receiver, two optical signals are detected through orthogonal polarizers and differentially amplified to remove the optical noise. In an environment that noise light from a fluorescent lamp is much stronger than the signal, the receiver with orthogonal polarizers removed the 120 Hz noise, and synchronous light transmission of the original and the reversed signals using two LEDs reduced the illumination flickering to about one-eighth that using one LED.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.9-15
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• 2005

The polariscope to measure the microscopic stress in CR lens consists of light source polarizer, model, polarizer, CCD, computer, chrome conversion orderly and the principal-stressed difference, (${\sigma}_1-{\sigma}_2$) and the fringe order n were measured by analyzing two components of light wave $E_1$ and $E_2$ following each polarizer's steps. The two-dimensional model could be determined from the fact that the optical axes of sample concide with the principal-stress directions. The bi-refringence acted to a light wave and the phase retardation were in proportion to the principal-stressed difference(${\sigma}_1-{\sigma}_2$) and the intensity of final light wave was proportioned to $sin2({\Delta}/2)$ and when ${\Delta}/2=n{\pi}$ (n=0, 1, 2, ${\ldots}$) the extinction occurs. Photoelastic's image by microscopic stress could analyzed using chrome conversion, and the image showed clearly.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.241-248
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• 2009

We suggest a new method to determine the off-alignment error of the composite film, together with in-plane($R_{in}$) and out-of-plane retardation($R_{th}$) of the compensation film, simultaneously. The composite film consists of a polarizing film and a compensation film for improvement of viewing angle of a liquid crystal display. We regarded the compensation film as o-plate with its optic axis along an arbitrary direction. By using an extended Jones matrix method, the polarization characteristics of the composite film are examined. The calculated Fourier constants, ($\alpha$, $\beta$) curves of the composite film as the azimuth angle is varied at the incident angles of $0^{\circ}$ and $50^{\circ}$, respectively, are used to determine the axis misalignment, the tilt angle and the azimuth angle of the compensation film by adopting the linear regressional analysis technique. Since this method can be applied for the inspection of the composite film even after laminating the polarizing film and the compensation film, it will be useful for simplifying the manufacturing process and reducing the production cost of liquid crystal display panels.

• Korean Journal of Optics and Photonics
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• v.31 no.4
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• pp.169-175
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• 2020

We design a polarization-independent dielectric multilayer thin-film diffraction grating for a spectral-beam-combining (SBC) system with a simple grating structure and low aspect ratio. To maintain the high quality of the SBC beam, we propose a multilayer mirror structure in which the wavefront distortion due to stress accumulation is minimized. Moreover, to prevent light absorption from contamination, an optimized design to minimize the grating thickness was performed. The optimally designed diffraction grating has 99.36% diffraction efficiency for -1st-order polarization-independent light, for incidence at the Littrow angle and 1055-nm wavelength. It is confirmed that the designed diffraction grating has sufficient process margin to secure a polarization-independent diffraction efficiency of 96% or greater.

• Korean Journal of Optics and Photonics
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• v.22 no.5
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• pp.219-222
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• 2011

Integrated optical waveguide polarization converters are among the essential components for constructing various functional optical integrated circuits. The RM materials have been widely used in liquid crystal displays for fabricating waveplates. In this work, the polarization converters are fabricated by using a solution of Reactive Mesogen(RM) dissolved in liquid crystal(LC). In the middle of the polymer waveguide, a groove is defined by an oxygen plasma etching in a direction perpendicular to the optical waveguide. The solution of RM-LC is inserted to fill up the groove, and then liquid crystal is aligned in a certain direction by applying an electric field. After the alignment, RM materal is crosslinked by UV light so as to form a permanent waveplate. The phase retardation of the waveplate is determined by the width of the groove, and by the birefringence and the degree of alignment of the LC. Polarization conversion efficiency of 90% is obtained for the wavelength of 1550 nm.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.55-62
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• 1996

This paper describes development of Polarized Stereo Monitoring System (KAERI-PSM) and compares the remote handling performance of KAERI-PSM with that of other monitoring systems, electric shutter type stereo monitoring system and general TV monitoring system. Remote handling performance is evaluated by total time and error number on remote operating experiments. Four kinds of remote handling experiments are carried out through 1) directly 2) general TV 3) electric shutter type monitor, and 4) KAERI-PSM. In these experiments six employees are participated and PUMA robot with force-torque reflectional joystic is used. The result of experiments show that camera angle against object is significant factor in monitoring and stereo monitoring system give more performance benifits in terms of accuracy and speed of remote handling operation than general TV monitoring system. In comparision of the polarized and electric shutter type stereo monitoring system, both have similar accuracy and speed for remote handling operation, but the former is superior in image quality and stability of the performance.