• Title, Summary, Keyword: Gratings

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Multiple light diffraction theory in volume gratings using perturbative integral expansion method

  • Jin, Sang-Kyu
    • Journal of the Optical Society of Korea
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    • v.1 no.2
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    • pp.67-73
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    • 1997
  • Light wave diffraction from multiple superposed volume gratings is inestigated using a perturbative iteration method of the integral equation of Maxwell's wave equation. The host material and index gratings are anisotropic and non-coplanar multiple volume gratings are considered. In this method, the paraxial approximation and lack of backward scattering in conventional coupled mode theory are not assumed. Systematic analysis of anisotropic wave diffraction due to multiple noncoplanar volume index gratings is performed in increasing level of diffraction orders corresponding to successive iterations.

Reproducible fabrication of diffraction gratings using holographic exposure system (홀로그래픽 간섭 노광계를 이용한 회절격자 제작의 재현성 향상)

  • 이동호
    • Proceedings of the Optical Society of Korea Conference
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    • pp.193-195
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    • 1989
  • A simple fabrication technique of diffraction gratings with short periods is presented. We can see that the monitoring of diffracted light from photoresist gratings during the development process provides optimum conditions for exposure and development processes. With this technique reproducibility and high quality of diffraction gratings is expected.

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Applying Moire Interference Patterns to Clothing Design through Gratings (격자 무아레(Moire) 무늬를 활용한 의상 디자인)

  • 김병미;육근철;임우경
    • Journal of the Korea Fashion and Costume Design Association
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    • v.6 no.2
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    • pp.15-20
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    • 2004
  • These days are referred to as 'the times of textile fashion,' owing to the emphasis on textile design in the fashion industry. Accordingly, apparel companies have increased their interests in developing new types of textiles to overcome the limits of style and silhouette. Now the ultra-fashion of textile, a new way of process and design development, is given much more attention. A Moire interference pattern has a longer wavy circle of interference, an effect of intensity interference, than one made by piling more than one reflecting plate or transmitting plate. Till now, Moire interference patterns have been used to confirm scientific theory and to measure the structure of a body or a subject in areas such as physics and medical science. Work has also been done on the Moire interference effects on TV screens said to cause dizziness and eye strain. This study focuses on the new types of textiles by creating the appearance of the Moire phenomena. Contrary to the present usual stationary patterns of textiles, it is a varying pattern according to the different gratings, different angles, piling gratings, and the movements of the human bodies. In the preceding study, we observed Moire fringes formed by overlapping two different or same kinds of gratings such as parallel line gratings, square gratings, conic gratings and semicircular gratings and tried to find a promising possibility of new textiles through the method of clothes design simulation.

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Measurements of Two-dimensional Gratings Using a Metrological Atomic Force Microscope with Uncertainty Evaluation

  • Kim, Jong-Ahn;Kim, Jae-Wan;Kang, Chu-Shik;Eom, Tae-Bong
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.2
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    • pp.18-22
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    • 2008
  • The pitch and orthogonality of two-dimensional (2-D) gratings were measured using a metrological atomic force microscope (MAFM), and the measurement uncertainty was analyzed. Gratings are typical standard devices for the calibration of precision microscopes, Since the magnification and orthogonality in two perpendicular axes of microscopes can be calibrated simultaneously using 2-D gratings, it is important to certify the pitch and orthogonality of such gratings accurately for nanometrology. In the measurement of 2-D gratings, the MAFM can be used effectively for its nanometric resolution and uncertainty, but a new measurement scheme is required to overcome limitations such as thermal drift and slow scan speed. Two types of 2-D gratings with nominal pitches of 300 and 1000 nm were measured using line scans to determine the pitch measurement in each direction. The expanded uncertainties (k = 2) of the measured pitch values were less than 0.2 and 0.4 nm for each specimen, and the measured orthogonality values were less than $0.09^{\circ}$ and $0.05^{\circ}$, respectively. The experimental results measured using the MAFM and optical diffractometer agreed closely within the expanded uncertainty of the MAFM. We also propose an additional scheme for measuring 2-D gratings to increase the accuracy of calculated peak positions, which will be the subject of future study.

Fabrication of Various Fiber Bragg Gratings Using the UV-Argon Laser (제2고조파 Argon Laser를 이용한 여러 가지 광섬유 격자의 제작)

  • 김승우;권재중;김성철;이병호
    • Proceedings of the IEEK Conference
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    • pp.309-312
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    • 1999
  • Fiber Bragg gratings have many applications such as fiber sensors, band-stop filters, add-drop filters, and mode convertors. In this paper, we present the fabrication method of various fiber Bragg gratings by using continuous wave UV-Argon(frequency-doubled Argon) laser. In our experiments, hydrogenation of fibers was used to enhance photosensitivity of fiber. And we fabricated fiber gratings by the phase mask method.

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Design of narrow band-pass filter using two fiber bragg gratings (광섬유 격자소자를 이용한 협대역 투과 필터의 설계)

  • 임종훈;이경식
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.8
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    • pp.82-88
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    • 1998
  • We propose and design a new type of anrrow band-pass optical filter based on two fiber gratings with different reflection wavelength. The ripples occur in the spectra of the filter with two uniform fiber gratings. Our simulation results also show that the ripples disappear with the fiber gratings apodized to both gaussian and hyperbolic tangent function. The hyperbolic tangent function seems to be a better apodization function for improving the filter's performance in terms of narrow pass bandwidth and high transmission.

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VPH Gratings for Near-Infrared Spectrographs

  • Lee, Sung-Ho;Deen, Casey;Chun, Moo-Young;Kim, Kang-Min;Yuk, In-Soo;Park, Chan;Oh, Hee-Young;Rukdee, Surangkhana;Jeong, Hwa-Kyung;Pak, Soo-Jong;Gully-Santiago, Michael;Lee, Han-Shin;Strubhar, Joseph;Rafal, Marc;Jaffe, Daniel
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.150.2-150.2
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    • 2011
  • Volume Phase Holographic (VPH) gratings are getting more popular as dispersion elements in spectrographs. High efficiency, compact configuration, and easy handling are driving many visual spectrographs to use VPH gratings for their main dispersers or for their cross-dispersers in higher resolution spectrographs. More recently, VPH gratings are being adopted in near-infrared by some spectrographs and by a number of next generation instrument projects. IGRINS (Immersion Grating Infrared Spectrograph) uses a VPH grating as a cross-disperser in each H or K band arm. J or H band performance of VPH gratings has been proven by other instruments. But K-band VPH gratings are new to the field. In this presentation, we are going to present test results we have got so far for verification of H-band VPH gratings and development of K-band VPH gratings.

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Measurements of Two-dimensional Gratings Using a Metrological Atomic Force Microscope and Uncertainty Evaluation (길이 표준 소급성을 갖는 원자간력 현미경을 이용한 2차원 격자 시편 측정과 불확도 평가)

  • Kim, Jong-Ahn;Kim, Jae-Wan;Kang, Chu-Shik;Eom, Tae-Bong
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.9
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    • pp.68-75
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    • 2007
  • The pitch and orthogonality of two-dimensional (2D) gratings have been measured by using a metrological atomic force microscope (MAFM) and measurement uncertainty has been analyzed. Gratings are typical standard artifacts for the calibration of precision microscopes. Since the magnification and orthogonality in two perpendicular axes of microscopes can be calibrated simultaneously using 2D gratings, it is important to certify the pitch and orthogonality of 2D gratings accurately for nano-metrology using precision microscopes. In the measurement of 2D gratings, the MAFM can be used effectively for its nanometric resolution and uncertainty, but a new measurement scheme was required to overcome some limitations of current MAFM such as nonnegligible thermal drift and slow scan speed. Two kinds of 2D gratings, each with the nominal pitch of 300 nm and 1000 nm, were measured using line scans for the pitch measurement of each direction. The expanded uncertainties (k = 2) of measured pitch values were less than 0.2 nm and 0.4 nm for each specimen, and those of measured orthogonality were less than 0.09 degree and 0.05 degree respectively. The experimental results measured using the MAFM and optical diffractometer were coincident with each other within the expanded uncertainty of the MAFM. As a future work, we also proposed another scheme for the measurements of 2D gratings to increase the accuracy of calculated peak positions.

Application passband filter of multiply cascaded phase-shifted long-period fiber gratings

  • Kim, Min-Sung;Han, Young-Geun;Kang, Dong-Joong;Ha, Jong-Eun;Kim, Jin-Young;Lho, Tae-Jung
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2496-2498
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    • 2005
  • The transmission characteristics of multiply cascaded phase-shifted long-period fiber gratings (LPFGs) will be investigated theoretically and experimentally. Their passband can be changed by increasing the number of ${\pi}$ -shifted LPFGs. When two ${\pi}$ -shifted LPFGs with different grating lengths are cascaded in series, the bandwidth of the rejection band and passband can be controlled by the pristine characteristics of two gratings.

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