• 정보저장시스템학회논문집
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• 제2권3호
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• pp.189-195
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• 2006

Bragg detuning effect if, one of the serious problems if the photopolymer is used for the recording material of holography memories. And the critical reasons of that are known as the bulk refractive index change and shrinkage of recording material. However, the trials for analyzing the effect are mainly on the K-sphere and biased on the transmission hologram. So, we approached Bragg detuning effect numerically and applied the method to the transmission holograms and the reflection holograms all together. We simulated it with MATLAB. As a result, the bulk refractive index change causes+Bragg detuning effect on the transmission holograms and the reflection holograms. But the shrinkage leads to+Bragg detuning effect on the transmission hologram and-Bragg detuning effect on the reflective hologram. Compared to experimental result, the bulk refractive index change(${\fallingdotseq}4{\times}10^{-4}$) and the ratio of shrinkage to the thickness of the material(${\fallingdotseq}1.67{\times}10^{-3}$) could be matched with Bragg detuning effect on the transmission hologram and the reflection hologram.

• 한국레이저가공학회지
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• 제17권2호
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• pp.19-25
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• 2014

Optical embedded diffraction gratings with the bulk modification in BK-7 glass plates excited by tightly focused high-intensity femtosecond (130fs) Ti: sapphire laser (peak wavelength = 790nm) were demonstrated. The structural modifications with diameters ranging from 400nm to $4{\mu}m$ were photo-induced after plasma formation occurred upon irradiation with peak intensities of more than $1{\times}1013W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around from the center of the point at which low-density plasma occurred. The maximum refractive index change was estimated to be $1.5{\times}10^{-2}$. The two optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

• 한국세라믹학회지
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• 제41권11호
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• pp.826-833
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• 2004

본 연구에서는 PLC 소자용 브래그 격자에 적용되는 재료인 Ge, B 등이 다량 첨가되어 있는 실리카 유리에서 발생하는 감광성(photosensitivity)을 조사하고 감광성의 발현 기구를 연구하였다. 관찰된 굴절률 변화의 최대값은 약 $10^{-3}$ 정도였으며 열처리 과정을 거치기 전후에 이러한 굴절률의 변화 양상이 변화하는 것을 관찰하였다. 이와 같은 굴절률의 변화를 UV 흡수도와 라만 스펙트림을 이용하여 본 연구의 시편에서 발생하는 감광성의 기구를 규명한 결과 굴절률 변화 요인이 유리 내에 존재하는 내부응력과 첨가된 B에 의하여 증대된 고밀화 과정에서 발생하는 현상임을 밝혔다.