npsm 새물리 New Physics : Sae Mulli

pISSN 0374-4914 eISSN 2289-0041
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Article

Research Paper

New Physics: Sae Mulli 2006; 52: 113-119

Published online February 1, 2006

Copyright © New Physics: Sae Mulli.

Study on Reading Signal of Super-RENS/ROM Disk Using Finite Difference Time Domain Method

Duck-Won AHN1, Chun-Yeol YOU1* and Kyong-Hon KIM1, Jin-Hong KIM2 and Keumcheol KWAK2

1Department of Physics, Inha University, Incheon 402-751
2Devices & Materials Lab, LG Electronics Institute of Technology, Seoul 137-724

Correspondence to:cyyou@inha.ac.kr

Abstract

We developed a numerical simulator in order to study the Super-RENS/ROM (Super REsolution Near-Field Structure, Read Only Memory) by using a 3-dimensional FDTD (finite-difference time domain) method. The simulation was performed in three steps. In the first step, we utilized vectordiffraction theory to calculate the characteristics of the incident laser beam from the object lens to the surface of the disk. In the second step, we used the calculated result as an input for the main FDTD simulations on the optical layers in the disk structure. After the FDTD simulations had been performed, for the reflected signal, we took a near-to-far field transformation from the surface of the disk to the detector. Finally, we obtained the reflected signal at the photo-diode. Using this developed simulator, we were able to study the reading signal from various disk structures as a function of the laser beam’s position. We calculated reading signals for a various pit sizes for Super-ROM structure, and we found that the simple optical diffraction theory could not explain the reading mechanism of a Super-ROM; more complicated temperature-dependent physics must be involved.

Keywords: Super-resolution, FDTD, Super-RENS, Super-ROM

Super-RENS/ROM (Super-REsolution Near-Field Structure, Read Only Memory)의 신호발생 원리를 이해하기 위해서 3차원 FDTD (finite difference time domain)방법을 이용한 전산모사 프로그램을 자체 제작하였다. 제작된 FDTD 전산모사 프로그램의 특징은 렌즈에서 디스크 표면까지 도달한 빛의 분포를 벡터회절 (Vector diffraction) 방법으로 계산을 하고 디스크 표면에서 디스크 내부까지는 FDTD로 계산을 수행한 이후에, 이 결과를 다시 근접장 (near field) 에서 원격장 (far field) 으로 변환하는 과정을 통하여 광 검출기에서 측정되는 신호를 계산하였다. 본 연구에서는 제작된 FDTD 전산모사 프로그램을 이용하여 광디스크 피트의 직경 및 깊이 변화와 입사 빔의 편광상태 변화에 따른 재생신호를 계산 및 해석하였다. 특히, 계산된 결과 값을 통하여 Super-ROM 디스크 구조의 신호발생 원리는 단순히 피트의 존재에 의한 기하학적 구조에 의한 것으로 설명 할 수 없음을 확인 할 수 있었다.

Keywords: <p>초해상, 유한차분시간구역 방법, Super-ROM</p>

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