• Title/Summary/Keyword: diffraction grating

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Visibility optimization of phase-shifting diffraction-grating interferometer (위상편이 회절격자 간섭계의 가시도 최적화)

  • 황태준;김승우
    • Korean Journal of Optics and Photonics
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    • v.14 no.6
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    • pp.643-648
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    • 2003
  • The phase-shifting diffraction-grating interferometer proposed in the investigation uses a diffraction grating that performs manifold functions of beam splitting, beam recombination, and phase shifting. The reference and measurement waves generated by means of diffraction have different amplitudes depending on their orders of diffraction, so the interference fringe pattern resulting from the two waves tends to yield poor visibility. To cope with this problem, we select a phase grating of reflection type and attempt to improve the interference visibility with optimization of the groove shape of the grating through electromagnetic analysis.

Fabrication and characterization of an optical demultiplexer using a concave diffraction grating (Concave 회절격자를 이용한 광분파기 제작과 특성 측정)

  • 강리할
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.227-231
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    • 1990
  • A SiO2/Si concave diffraction grating(period: 1.3${\mu}{\textrm}{m}$) for the angular dispersive element of WDM was fabricated by sandwiching the SiO2/Si plane diffraction grating between a slab waveguide and a cylindrical concave block. Using this concave grating and input/output fiber, and wavelength division demultiplexer was composed. The demultiplexer has five channels, the insertion loss of 30dB, the wavelength spacing per channel of 7nm and crosstalk of-15dB.

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Feasibility Study of the Light-outcoupling Characteristics of a Diffraction-grating-imprinted Light-guide Plate for an LCD Backlight Unit (LCD 백라이트 유닛의 서브 마이크론 회절 격자 도광판의 광 출사 특성 연구)

  • Choi, Hwan Young
    • Korean Journal of Optics and Photonics
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    • v.31 no.4
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    • pp.176-182
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    • 2020
  • The possibility of replacing the condensing-prism film used in conventional backlight units with a light-guide plate engraved with a submicrometer-periodic diffraction grating was investigated. The optimal period for the diffraction grating was determined through simulation and experiment, and the transmission-mode efficiency of the diffraction grating was calculated in terms of the polar angle and azimuthal angle of the incident light. In addition, the effects of the two methods of optimizing the polar angle and the directional angle were compared by simulation, by suggesting the shape and configuration of the light-guide plate, so that more light could be extracted by diffraction. By using a ray-tracing program, the luminance angular distribution of the light-guide plate engraved with the diffraction grating was calculated and compared to the luminance angular distribution for each actual prototype.

Diffraction-efficiency Correction of Polarization-independent Multilayer Dielectric Gratings (무편광 유전체 다층박막 회절격자의 효율 보정)

  • Cho, Hyun-Ju;Kim, Gwan-Ha;Kim, Dong Hwan;Lee, Yong-Soo;Kim, Sang-In;Cho, Joonyoung;Kim, Hyun Tae
    • Korean Journal of Optics and Photonics
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    • v.33 no.1
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    • pp.22-27
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    • 2022
  • We fabricate a polarization-independent dielectric multilayer thin-film diffraction grating for a spectral-beam-combining (SBC) system with a simple grating structure and low aspect ratio. Due to the refractive index and thickness error of the manufactured thin films, the diffraction efficiency of the fabricated diffraction grating was lower than that of the design. The causes of the errors were analyzed, and it was confirmed through simulation that diffraction efficiency could be compensated through an additional coating on the manufactured diffraction grating. As a result of sputtering an additional Ta2O5 layer on a fabricated diffraction grating, the diffraction efficiency was corrected and a maximum 91.7% of polarization-independent diffraction efficiency was obtained.

Amorphous chalcogenide thin films of relief grating formation by using He-Cd laser (He-Cd 레이져를 이용한 비정질 칼코계나이드 박막의 relief 격자 형성)

  • Lee, Ki-Nam;Park, Jung-Il;Yang, Sung-Jun;Lee, Young-Jong;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1058-1061
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    • 2003
  • In this thesis, we observed the optical characteristic of amorphous chalcogenide thin films by He-Cd laser. Also, grating formation by He-Ne laser and He-Cd laser. After analyze diffraction efficiency of the time on the $Ag(200{\AA})/As_{40}Ge_{10}Se_{15}S_{35}$ thin films. The result diffraction efficiency of Maximun 0.2% reduced according to time grating formation by He-Ne laser. Diffraction efficiency of Maximun 0.1% showed stabiliy characteristic according to time grating formation by He-Cd laser.

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An implementation of the efficient optical perfect shuffle interconnection with block-quantized binary phase hologram (Block-Quantized 이진 위상 홀로그램을 이용한 효율적인 광학적 perfect shuffle의 구현)

  • Kim, Hee-Ju;Huh, Hyun;Pan, Jae-Kyung
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.5
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    • pp.125-131
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    • 1996
  • In this paper, we introduced the BQBPH method for making the grating of high efficiency which was improtant in implementing optical PS. The pattern of graing was obtianed by computer simulations using iterative method, and the diffraction efficeincy of designed grating was about 67% through BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency was 47%. We implemented the optical PS with the grating and showed that optical experimental output patterns were good agreement with PS output patterns and first order was main diffraction order.

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Design of a Simply Structured High-efficiency Polarization-independent Multilayer Dielectric Grating for Spectral Beam Combining (SBC 시스템 구성을 위한 단순한 구조를 가지는 고효율 무편광 유전체 다층박막 회절격자 설계)

  • Cho, Hyun-Ju;Kim, Gwan-Ha;Kim, Dong Hwan;Lee, Yong-Soo;Kim, Sang-In;Cho, Joonyoung;Kim, Hyun Tae;Kwak, Young-seop
    • Korean Journal of Optics and Photonics
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    • v.31 no.4
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    • pp.169-175
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    • 2020
  • We design a polarization-independent dielectric multilayer thin-film diffraction grating for a spectral-beam-combining (SBC) system with a simple grating structure and low aspect ratio. To maintain the high quality of the SBC beam, we propose a multilayer mirror structure in which the wavefront distortion due to stress accumulation is minimized. Moreover, to prevent light absorption from contamination, an optimized design to minimize the grating thickness was performed. The optimally designed diffraction grating has 99.36% diffraction efficiency for -1st-order polarization-independent light, for incidence at the Littrow angle and 1055-nm wavelength. It is confirmed that the designed diffraction grating has sufficient process margin to secure a polarization-independent diffraction efficiency of 96% or greater.

Fabrication of Diffraction Grating Mold Using Dot Pattern (도트 패턴을 이용한 회절 격자 금형 제작)

  • Noh, Ji-Whan;Lee, Jae-Hoon;Sohn, Hyon-Kee;Suh, Jeong;Shin, Dong-Sig;Joung, Young-Un
    • Laser Solutions
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    • v.9 no.3
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    • pp.1-5
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    • 2006
  • Diffraction grating is the optical device which has periodic pattern. Decorative logotypes is the one of application of diffraction grating. In this paper diffraction grating for decorative logotype is fabricated by dot pattern in stead of line pattern. A metallic mold for diffraction gratings is fabricated with a mode-locked 12 ps Nd:YVO4 laser. Laser pulses with a wavelength of 355nm are irradiated on the surface of NOK 80, a mold material, to generate dot patterns. In order to minimize the dot diameter, laser power is set just above the ablation threshold of NOK 80. Results show that the spectrum from the fabricated mold is good enough for some industrial application

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Fabrication of diffraction grating mold using dot pattern (도트 패턴을 이용한 회절 격자 금형 제작)

  • Noh, Ji-Whan;Lee, Jae-Hoon;Sohn, Hyon-Kee;Suh, Jeong;Shin, Dong-Sig;Joung, Youn-Gun
    • Proceedings of the Korean Society of Laser Processing Conference
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    • 2006.11a
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    • pp.114-117
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    • 2006
  • Diffraction grating is the optical device which has periodic pattern. Decorative logotypes is the one of application of diffraction grating. In this paper diffraction grating for decorative logotype is fabricated by dot pattern in stead of line pattern. A metallic mold for diffraction gratings is fabricated with a mode-locked 12 ps $Nd:YVO_4$ laser. Laser pulses with a wavelength of 355nm are irradiated on the surface of NOK 80, a mold material, to generate dot patterns. In order to minimize the dot diameter, laser power is set just above the ablation threshold of NOK 80. Results show that the spectrum from the fabricated mold is good enough for some industrial application.

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Holographic Grating Formation of Amorphous AsSeS Thin Film (비정질 AsSeS 박막의 홀로그래픽 데이터 격자형성)

  • Ju, Long-Yun;Lee, Song-Hee;Nam, Ki-Hyun;Koo, Sang-Mo;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.447-448
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    • 2008
  • In this paper, we investigated the diffraction grating efficiency on AsSeS and Ag-doped amorphous chalcogenide Ag/AsSeS thin film for used to volume hologram. The film thickness was 0.5um and diffraction efficiency was obtained from (P:P) polarized He-Ne (632.8nm)laser beam on AsSeS and Ag/AsSeS thin films. As a results, diffraction grating was not formed at AsSeS thin film but at Ag-doped AsSeS thin film, diffraction grating was formed well compare with the former.

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