• Title/Summary/Keyword: cut off 파장

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An Ultra-thin IR Cut-off Filter Based on Nanostructures (나노구조 기반 초박형 적외선 차단 필터)

  • Hyundo Yang;Jong-Kwon Lee
    • Korean Journal of Optics and Photonics
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    • v.35 no.1
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    • pp.24-29
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    • 2024
  • We propose a hyperbolic metastructure based on a nanopatterned metal (Ag)-dielectric (PDMS) multilayer and report on its performance in an infrared (IR) cut-off filter for imaging devices. By optimizing the size of the square-shaped Ag nanopattern and the thickness of PDMS surrounding the Ag nanopattern, the proposed IR cut-off filter blocks 99% of light in the 0.70-1.01 ㎛ wavelength band while maintaining a high transmittance of over 94% in the visible region. Here, the cut-off wavelength band starts at a region above the epsilon-near-zero wavelength of the hyperbolic metastructure and ends at the point where plasmonic absorption appears strongly. It is observed that transmittance in the wavelength region longer than the IR cut-off band increases again due to plasmonic coupling among horizontally adjacent Ag nanopatterns. This metastructure can improve the performance of IR-blocking filters as well as allow it to be manufactured ultra-thin, which is applicable to various planar optical elements and integrated optical components.

Measurement of Spectral Loss and Cut-off Wavelength of Single Mode Opticla Fiber by Variable Wavelength (파장변화에 따른 단 모드 광섬유의 스펙트랄 로스 및 차단파장 측정)

  • Hong, Bong Sik;Han, Byoung Sung;Koo, Kyoung Wan
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.23 no.2
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    • pp.264-268
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    • 1986
  • A thchnique has been studied for the measurement of the spectral loss and the cut-off wave length, at which the first high-order mode disappears. The near-field patterns of a fiber which is excited by a variable wavelength source are used for the measurement of cut-off wavelength. Because of the absorptive phenomenon of OH- molecular vibration, spectral loss of a single mode optical fiber sample is 5.6dB/km at 1380 nm wavelength and 1dB/km at 1240 nm wavelength. From the near field intensity patterns and the mode field diameter graph for the half power width, the cut-off wavelength of the fiber is measured to be 1120 nm.

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Correction and Evaluation for Color Aberration on the Cut-off Line of a Vehicle Headlamp (차량용 헤드램프의 Cut-off Line에서 색수차 보정 및 평가)

  • Shim, Ju Yong;Park, Sung-Chan
    • Korean Journal of Optics and Photonics
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    • v.30 no.1
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    • pp.8-14
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    • 2019
  • This paper presents methods to correct and evaluate the chromatic aberration occurring on the cut-off line of a headlamp without additional optical components and alignment process. To correct the chromatic aberration using a geometrical concept, the maximum differences in exit-ray angle between wavelengths are reduced by tilting the convex surface of an aspheric projection lens. To evaluate the chromatic aberration, the position and luminous intensity to be measured are suggested, and the criterion for chromatic aberration is presented through color coordinates. From the evaluation of an automotive headlamp designed using this geometrical method, it is found that the chromatic aberration of the cut-off line is significantly reduced.

650nm IR Cut-off 필터의 제작 및 특성

  • Sin, Gwang-Su;Kim, Jin-Hyeok;Gi, Hyeon-Cheol;Kim, Hyo-Jin;Go, Hang-Ju;Kim, Seon-Hun;Kim, Du-Geun;Han, Myeong-Su
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.169-169
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    • 2010
  • 650nm 적외선 차단 필터를 Macleod 프로그램을 이용하여 설계하고, 이온보조증착(IAD) 장비를 이용하여 코팅한 후 투과도, 파장, 두께특성을 조사하였다. 차단필터의 증착물질은 $TiO_2$ (n=2.30) /$SiO_2$ (n=1.46) 을 사용하여 45층의 다층 박막으로 증착하였다. 코팅된 차단필터는 차단파장이 651 nm로써 평균 ${\pm}5$ nm 이내의 편차를 보였다. 420~630 nm 파장영역에서 평균 투과도는 89%이었으며, 투과도의 균일도는 약 2.12로써 매우 균일하였다. 투과도기 단파장 영역에서 감소된 것은 다층박막 증착 시 산소가 결핍된 것으로 판단된다.

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Change of Contrast Sensitivity Induced by Tinted Spectacle Lens (칼라필터 렌즈에 따른 대비감도의 변화)

  • Seo, Jae-Myoung
    • Journal of Korean Ophthalmic Optics Society
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    • v.21 no.1
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    • pp.47-51
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    • 2016
  • Purpose: The purpose of this study was to investigate the change of contrast sensitivity by prescribing tinted lenses and to provide the clinical manual. Methods: Contrast sensitivity was measured for twenty adults with normal vision while they wore yellow, orange and green tinted lenses. To measure contrast sensitivity, the 5 spatial frequencies (2, 4, 6, 8 and 10 cpd) were used for 33 ms and 233 ms, respectively. Results: The contrast sensitivity was overall higher with 233 ms than 33 ms (p<0.05). The peaks of contrast sensitivity with 33 ms and 233 ms were 1.75 log unit with the yellow lens and 1. 85 log unit without the color respectively. However, there was no significance between the yellow and orange tinted lens (p>0.64) Conclusions: Yellowish tinted lens that reduces chromatic aberration and the scattering is prescribed for the various purposes to improve visual functions. Before prescribing tinted lens, identifying characteristic of user and tinted lens for cut off wavelengths is recommended.

Discussion on the Effect of Improving the Image of a Fingerprint Shape Using a Forensic Light Source with Low-pass Filter (Low-pass 필터가 장착된 법과학 광원을 이용한 지문의 형광 이미지 개선 효과에 대한 논의)

  • Lee, A-Ram;Seo, Bo-Gil;Kim, Ju-Bi;Kim, Duke;Yu, Je-Seol
    • The Journal of the Korea Contents Association
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    • v.19 no.12
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    • pp.527-534
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    • 2019
  • Most of the prints left on the crime scene are latent prints. And, even after the latent prints have been developed, additional enhancement is required and forensic light sources are mainly used. Depending on the applied technique and the light source used, it is difficult to obtain the ideal enhancement effect when the reflected light cannot be cut off well. In this study, we improved the wavelength of the forensic light source by attaching a low-pass filter, resulting in better quality fingerprint images.

Growth of HgCdTe thin film by the hot-wall epitaxy method (Hot-wall epitaxy 방법에 의한 HgCdTe 박막 성장)

  • 최규상;정태수
    • Journal of the Korean Vacuum Society
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    • v.9 no.4
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    • pp.406-410
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    • 2000
  • Using the hot-wall epitaxy method, we grew a $Hg_{1-x}Cd_xTe$ (MCT) thin film in-situ after growing (111) CdTe of 9 $mu \textrm{m}$ as a buffer layer. The value of FWHM of double crystal x-ray diffraction rocking curve was 125 arcsec and the surface morphology was clean with a small roughness of 10 nm. From measuring the photocurrent of the grown MCT thin film, the maximum peak wavelength and the cut-off wavelength were 1.1050 $\mu\textrm{m}$ (1.1220 eV) and 1.2632 $\mu\textrm{m}$ (0.9815 eV), respectively. This peak wavelength corresponds to the peak of the band gap due to the intrinsic transition of the photoconductor. Therefore, the MCT thin film could be used as the photoconducting detector sensing a near-IR wavelength band from 1.0 to 1.6 $\mu\textrm{m}$.

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Properties of Multicomponent Glass Optical Fiber by adding $Ga_2O_3$ ($Ga_2O_3$ 첨가에 따른 다성분계 glass optical fiber의 특성)

  • 윤상하;강원호
    • Electrical & Electronic Materials
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    • v.10 no.3
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    • pp.210-216
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    • 1997
  • The th ermal and optical properties of multicomponent oxide glass optical fiber by adding heavy metal oxide Ga$_{2}$O$_{3}$(0-20wt%) were investigated. The fiber samples were made by the method of rod in tube. The optical loss of fiber was measured in 0.3-1.8.mu.m wavelength region. As Ga$_{2}$O$_{3}$ increased up to 20wt%, the transition and softening temperature of bulk glass were increased from 495.deg. C to 579.deg. C and from 548.deg. C to 641.deg. C, respectively. Whereas the thermal expansion coefficient was decreased from 102 to 79.1x10$^{-7}$ /.deg. C. The refractive index was increased from 1.621 to 1.665, and IR cut-off wavelength was enlarged from 4.64.mu.m to 6.1.mu.m. The optical loss of fiber was remarkably decreased in 1.146.mu.m-1.8.mu.m wavelength region.

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Properties of glass fiber by adding $Ga_2O_3$ in the $SiO_2-PbO-K_2O-Al_2O_ 3$ system for infrared sensor ($Ga_2O_3$ 첨가에 따른 $SiO_2-PbO-K_2O-Al_2O_ 3$계 적외선 센서용 glass fiber의 특성)

  • 이명원;윤상하;강원호
    • Electrical & Electronic Materials
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    • v.9 no.10
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    • pp.1047-1052
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    • 1996
  • In this study, the thermal and optical proper-ties of multicomponent oxide glass fiber for IR sensor by adding heavy metal oxide Ga$_{2}$O$_{3}$ were investigated. The fiber samples were made by rod-in tube method. The optical loss of fiber was measured in 0.3-1.8/M wavelength region. As Ga$_{2}$O$_{3}$ increased up to 12wt%, the transition and softening temperature of bulk glass were increased from 495.deg. C to 564.deg. C and from 548.deg. C to 612.deg. C respectively. Whereas the thermal expansion coefficient was decreased from 102 to 88.2*10$^{-7}$ /.deg. C. The refractive index was increased from 1.621 to 1.662, and IR cut-off wavelength was enlarged from 4.64.mu.m to 5.22.mu.m. The optical loss of fiber was decreased and more remarkably decreased in 1.146.mu.m-1.8.mu.m wavelength region.

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