• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.164-169
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• 2024

We applied recursive numerical computation to create a basic design of a camera optical module for mobile phones. To enhance the resolution performance for a 38-degree field of view, we constructed the optical system with six non-spherical lenses. However, to increase its applicability to a compact mobile phone, we limited the overall length to 5 mm in the design. Using the data obtained from the basic design, we proceeded with optimization design using the Zemax design tool. The optimized optical system achieved a resolution performance with a modulation transfer function value of more than 19% for a 280 lines/mm pattern and image distortion within 1.0% for all wavelength rays. In this paper, we verify the feasibility of using recursive numerical computation for the basic design of a compact mobile phone camera.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.142-145
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• 1998

It is shown that the optical system with Gaussian pupil e, diffraction amplitude distribution is not affected by the presence of residual aberrations. The case of spherical aberration is treated, as an example, and the complex diffraction amplitude distribution at the neighbourhood of the image point is described analytically by using a recurrence formula.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.418-422
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• 1994

본 연구에서는 MOVPE를 이용한 MQW활성층을 DFB-LD 구조에 도입함으로서 2.5Gbps 광전송용 광원으로 사용된 $ 1.55.\mu$m 파장의 MQW-PBH-DFB-LD를 제작하였다. 활성층으로는 MOVPE를 이용하여 8쌍의 InGaAs/InGaAsP MQW층을 성장하였으며 2차 및 3차 결정성장은 LPE를 사용하였고 발진파장을 결정하는 회절격자 주기는 238nm로 하였다. MQW-PBH-DFB-LD의 평균 임계전류는 13.81mA, Slope efficiency는 0.137mW/mA이었고 발진파장은 1548.6nm의 특성을 얻었다. 그리고 2.5Gbps 대신호 변조시의 chirping특성을 조사하여 본 결과 0.55nm임을 확인할 수가 있었다.

• Journal of the Korean Vacuum Society
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• v.4 no.4
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• pp.407-412
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• 1995

TIGaSe2:Ho 결정에 대한 간접전이 에너지간격의 온도의존성은 각각 1차 상전이와 2차 상전이에 상당하는 100K와 108K에서 변칙특성을 보여주었다. TIGaSe2:Ho 결정에서 Ho3+이온에 긴인된 5I8$\longrightarrow$5I7과 5I8$\longrightarrow$5F5의 두 광학적 전이가 광흡수와 광전도도 스펙트라로부터 관측되었다. TIGaSe2와 TIGaSe2:Ho 결정의 열자극전류로부터 고유결함과 Ho 불순물에 관련된 양공 덫을 발견하였다.

• Optical Science and Technology
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• v.11 no.3_4
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• pp.5-11
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• 2007

제1형의 SPDC에서 발생한 광자쌍의 얽힘특성과 연관된 간섭실험들을 소개하였다. 양자역학적으로 두-광자 간섭현상은 간섭계에서 동시계수가 가능한 경로에 대한 확률진폭들의 결맞음으로부터 일어나며, 이는 측정과정에서의 경로에 대한 구별 불가능성과 연관된다. HOM 간섭계에서는 BS에 도달하는 두 광자의 시간차가 없을 때, BS의 출구에서 광자들이 쌍을 이루는 시간적인 두-광자 간섭효과를 관측하였다. SPDC에서 발생하는 넓은 파장영역의 광자들 중에서 서로 다른 두 파장의 광자쌍을 선택하는 경우에도 동시계수측정에서 두 광자의 경로를 구별할 수 없는 경우에는 두 광자의 진동수 차이에 해당하는 주기로 동시계수가 변하는 간섭효과를 관측할 수 있다. 또한 HOM 간섭계에서 BS에 입사하는 두 광의 각도를 변화시키면 광자쌍의 공간적인 4차 간섭현상을 관측할 수 있다

• Korean Journal of Optics and Photonics
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• v.25 no.1
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• pp.8-13
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• 2014

By using finite ray-tracing and curve fitting, a numerical method to determine the non-paraxial pupil function of a high-NA objective is presented. MTF degradations caused by the non-paraxial diffraction effect are analyzed for on-axial imaging of a far-infrared objective and aberration-free ellipsoidal mirror system. The ellipsoidal mirror system has the same paraxial specifications as the far-infrared objective.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.58-59
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• 2001

최근 홀로그래픽 데이터 저장 국제 워크샵(International Workshop on Holographic Data Storage)에서 발표된 자료에 따르면 광메모리 데모 시스템들의 저장 용량이 100MB~150GB에 달하고 있으며, page당 용량은 1백만 비트(1000$\times$1000 bits)이상, 데이터 전송 속도는 1Gbit/sec에 이르고 있다. 반면에 현재까지는 상용화 단계의 시스템은 발표되지 않고 있다. 본 논문에서는 이들 시스템과 성능 차이는 많이 나지만 그 동안의 광굴절 결정의 특성 실험결과와 각각의 광학 시스템의 연구 결과들을 토대로 디지털 데이터를 기록하고 재생할 수 있는 초기 자동화된 데모 시스템을 구현하였다. (중략)

• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.127-132
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• 1991

We have obtained the analytic solutions of the four spherical mirror system free from the Seidel third order aberratios which are spherical aberration, coma, astigmatism, and distortion, Vignetting. Petzval field curvature, and optical properties according to the design parameters are numerically investigated and optimized. The numerical aperture of this system is 0.2 and the half field angle is $1.5^{\circ}$.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.337-344
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• 2007

In recent years, there has been rapid progress in different areas of vision science, such as refractive surgical procedures, contact lenses and spectacles, and near vision. This progress requires a highly accurate modeling of optical performance of the human eyes in different accommodation states. A new novel model-eye was designed using the Navarro accommodation-dependent finite model eye. For each of the vergence distances, ocular wavefront error, accommodative response, and visual acuity were calculated. Using the new model eye ocular wavefront error, accommodation dative response, and visual acuity are calculated for six vergence stimuli, -0.17D, 1D, 2D, 3D, 4D and -5D. Also, $3^{rd}\;and\;4^{th}$ order aberrations, modulation transfer function, and visual acuity of the accommodation-dependent model eye were analyzed. These results are well-matched to anatomical, biometric, and optical realities. Our corrected accommodation-dependent model-eye may provide a more accurate way to evaluate optical transfer functions and optical performances of the human eye.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.93-98
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• 2014

Purpose: We were aim to investigate individual difference of visual acuity (VA) decrease and the change of contrast threshold (CT) according to the level of optically induced retinal defocus. Methods: A total of 69 eyes were examined using consist of ten-graded decimal vision chart (Landolt's ring). After conducted full correction of subject's refractive error, a monocular VA and CT were measured according to sequential increase by 0.25 D each time. Results: VA gradually decreased according to the increase of retinal defocus level. Individual difference of VA decrease was range from 1.2 to 0.6 in retinal defocus induced by +0.25 D. When retinal defocus was induced as much as +0.50 D and +0.75 D, it was in the range of 1.0 to 0.3 and 0.9 to 0.1 respectively. With +1.00 D, some participants didn't even recognize the 0.1 in the chart. With +1.75 D, whole participant did not recognize the 0.1. Also, CT was gradually decreased with increase of the retinal defocus level. Conclusions: Examiners should consider individual difference in the decrease of VA according to the level of residual refractive error when determining final prescription of a patient.