• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.89-92
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• 1998

Amorphous chalcogenide thin films, especially a-(Se, S) based films, exhibit a number of photoinduced phenomena not observed in other types of amorphous thin films. The polarization holographic grating has been formed in amorphous As-Ge-Se-S thin films using two linearly polarized He-Ne laser light. In addition, dffraction efficiency has been measured by the same laser of a relative lower intensity at the same time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.87-90
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• 1999

The dependence of diffraction efficiency as a funct~on of film thickness and incident angle has been investigated in amorphous chalcogenide thin films, which act as a polarization holographic materials. Especially a-(Se, S) based films exhibit a number of photoinduced phenomena not observed in other types of amorphous thin films. Holographic gratings in amorphous As-Ge-Se-S thin films have been formed using the mutual perpendicular polarized(linearly) He-Ne laser light. We could obtain the optimum condition to get high diffraction efficiency.

• Macromolecular Research
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• v.9 no.6
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• pp.339-344
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• 2001

In order to investigate the photoalignment mechanism of nematic liquid crystals on a polymer film, a new photoreactive polymer having chalcone groups as side chains was synthesized. Linearly polarized UV light causes preferential photoreactions of the chalcone unit along the polarization direction and thus induces the anisotrpy in the polymer alignment layer resulting in homogeneous LC alignment perpendicular to the polarization direction. The sequential investigations of photoalignment generated by the preferential E/Z isomerization and (2+2) cycloaddition reactions show that either photoreaction can solely induce the LC alignment in the direction perpendicular to UV polarization.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.1
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• pp.31-39
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• 1991

The polarization properties of low birefringent optical fiber due to intrinsie birefringence and magnetooptic effects are theoretically analyzed and experimented. The low birefringent fiber is fo¬und to have more excellent polarization maintaining properties than normal single mode optical fiber. As the experimental results, the polarizability of low birefringent optical fiber is measured over 0.818. The variation of output polarization angle with input polarization angle is measured within $9^{\circ}$. Imple¬mented magnetic field measuring system using low birefringent optical fiber can linearly measure the magnetic field strength up to lOkAT generated by solenoid. The maximum error is 1.95% in the magnetic field strength of 4kAT.

• Current Optics and Photonics
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• v.2 no.5
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• pp.474-481
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• 2018

We propose a polarization phase-shifting technique to investigate the thickness of $Ta_2O_5$ thin films deposited on BK7 substrates, using a modified Sagnac interferometer. Incident light is split by a polarizing beam splitter into two orthogonal linearly polarized beams traveling in opposite directions, and a quarter-wave plate is inserted into the common path to create an unbalanced phase condition. The linearly polarized light beams are transformed into two circularly polarized beams by transmission through a quarter-wave plate placed at the output of the interferometer. The proposed setup, therefore, yields rotating polarized light that can be used to extract a relative phase via the self-reference system. A thin-film sample inserted into the cyclic path modifies the output signal, in terms of the phase retardation. This technique utilizes three phase-shifted intensities to evaluate the phase retardation via simple signal processing, without manual adjustment of the output polarizer, which subsequently allows the thin film's thickness to be determined. Experimental results show that the thicknesses obtained from the proposed setup are in good agreement with those acquired by a field-emission scanning electron microscope and a spectroscopic ellipsometer. Thus, the proposed interferometric arrangement can be utilized reliably for non-contact thickness measurements of transparent thin films and characterization of optical devices.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.36.2-36.2
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• 2015

We report the first detection of linearly polarized emission at an observing wavelength of 350 mum from the radio-loud active galactic nucleus 3C 279. We conducted polarization observations for 3C 279 using the SHARP polarimeter in the Caltech Submillimeter Observatory on 2014 March 13 and 14. For the first time, we detected the linear polarization with the degree of polarization of $13.3%{\pm}3.4%$ (3.9sigma) and the electric vector position angle (EVPA) of $34.^{\circ}7{\pm}5.^{\circ}6$. We also observed 3C 279 simultaneously at 13, 7, and 3.5 mm in dual polarization with the Korean very long baseline interferometry (VLBI) Network on 2014 March 6 (single dish) and imaged in milliarcsecond (mas) scales at 13, 7, 3.5, and 2.3 mm on March 22 (VLBI). We found that the degree of linear polarization increases from 10% to 13% at 13 mm to 350 mum and the EVPAs at all observing frequencies are parallel within < $10^{\circ}$ to the direction of the jet at mas scale, implying that the integrated magnetic fields are perpendicular to the jet in the innermost regions. We also found that the Faraday rotation measures RM are in a range of $-6.5{\times}102{\sim}-2.7{\times}103$ rad m-2 between 13 and 3.5 mm, and are scaled as a function of wavelength:| {RM}| ${\backslash}propto$ {lambda }-2.2. These results indicate that the millimeter and sub-millimeter polarization emission are generated in the compact jet within 1 mas scale and affected by a Faraday screen in or in the close proximity of the jet.

• ETRI Journal
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• v.25 no.1
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• pp.41-48
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• 2003

This paper presents a theoretical investigation of power reflection and transmission coefficients for a meander-line polarizer placed periodically on a chiral slab. It is assumed that a linearly polarized transverse magnetic wave is incident on a chiral slab from the air region. In the analysis, we derive the electric and magnetic fields in the modal form in the air and chiral regions. We obtain power reflection and transmission coefficients in a straightforward manner after matching the tangential components of the electric and magnetic fields at the boundaries. We present numerical results for the power reflection and transmission coefficients versus frequency and incident angle for different values of the chirality admittance. A meander-line polarizer placed on a dielectric slab can convert a linearly polarized wave to a circularly polarized wave. The design parameters for a meander-line polarizer are the dimensions of the meander-line and the values of the dielectric slab. Replacing a dielectric slab with a chiral slab introduces a new independent parameter which controls the wave polarization.

• The Journal of Natural Sciences
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• v.17 no.1
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• pp.31-37
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• 2006

We have found that the polarization mode coupling between the orthogonally linearly polarized dual mode laser results from the anisotropy of dipole moments. Rate equation analysis demonstrated that high anisotropy in dipole moment components can give rise to law intrinsic mode coupling constants while isotropic dipole moment components give high intrinsic mode coupling constant. The populations at active ion sites are shown to self-organize the populations such that laser mode gain is constant adove threshold while the gain contributions from the each site adjust themselves with pump power.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.744-747
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• 2001

This paper shows shear wave behavior of CFRP composite laminates as a polar grid form to evaluate vibration pattern of ultrasonic transducers, which gives measured modelling fundamental contents of nondestructive evaluation. Polarized direction can be obtained by using a c-scanner and sensitivity of transducers is founded when using through-transmission method of two transducers. And modelling of vector decomposition is presented based on ply-to-ply method to apply practicable nondestructive evaluation of CFRP laminate lay up. This modelling decomposes the transmission of linearly polarized wave into orthogonal components through each ply of a laminate. It is found that a high provable shows between the model and experimental developed in characterizing layup of CFRP composite laminates.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.473-477
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• 2003

In this paper, a integrated structure of a two-element microstrip patch antenna with two feeds for GPS/PCS dual-band operation is proposed. The radiating element for PCS operation is a novel broad band low-profile cylindrical monopole top-loaded with a shorted meander patch, which gives linearly polarized conical radiation pattern and size reduction of patch due to meander line. The radiating element for GPS operation is a novel square-ring microstrip patch with truncated corners and slits. which provide circularly polarized broadside radiation patterns and size reduction due to slots. using dielectric substrate in GPS antenna of proposed antenna provide to improve isolation between two feeds and reduce size of patch. The proposed antenna achieves the bandwidth and polarization requirements of GPS and PCS systems.