• Broadcasting and Media Magazine
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• v.16 no.2
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• pp.73-83
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• 2011

홀로그래픽 광학소자(HOE; holographic optical elements)는 높은 회절효율과 협대역 주파수 특성, 그리고 여러 가지 기능을 하나의 소자로 구현할 수 있다는 특성을 갖고 있어 비행기와 자동차의 정보 표시를 위한 HUD(head-up display), 증강현실용 HMD(head mounted display), 2D/3D 디스플레이용 스크린 등에 널리 활용되고 있다. 이에 홀로그래픽 광학소자(HOE)의 동작특성과 디스플레이에 활용되고 있는 몇 가지 예를 통해 그 활용가치와 앞으로 홀로그래픽 광학소자가 좀 더 보편화되기 위해 풀어야 할 당면과제 등에 대해 다루고자 한다.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.418-424
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• 2001

A holographic HMD element having low aberrations and high diffraction efficiency over wide FOV has been fabricated. In order to design the HOE having low aberrations a recursive technique was used. To obtain the HOE having low aberrations as well as high diffraction efficiency over a wide FOV, we used an intermediate hologram and the grating function of the aberration corrected hologram was transferred to the final hologram through it. For the fabricated final HMD element, we got the results of spot size improved about 10 times and high diffraction efficiency over FOV of $\pm$10$^{\circ}$.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.110-111
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.136-137
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• 2002

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.273-274
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• 2009

• Korean Journal of Optics and Photonics
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• v.11 no.1
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• pp.47-57
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• 2000

A two-stage iterative Fourier transform algorithm, based on hybrid input-output algorithm and new Pnoise algorithm, is used to design continuous and quantized phase-only diffractive pattern elements which produce arbitrary given intensity patterns via Fraunhofer diffraction. Numerical results for two $128\times128$ binary patterns and two grayscale patterns are compared with those of other algorithms. It is found that the algorithm yields better signal-to-noise ratio and even better uniformity with slightly lower diffraction efficiency than other algorithms. We investigated the dependence of performance on parameters used in the algorithm, size of noise region, and the number of phase levels for quantized elements. In the case of quantized phase elements, the size of noise region plays a greater role in determining the performance of the algorithm than given intensity pattern itself. tself.

• Proceedings of the Optical Society of Korea Conference
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• 2001.08a
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• pp.80-81
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• 2001

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.348-353
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• 1999

Ray-optics approach based on the rigorous coupled wave theory, called by the rigorous ray-optics method (RROM), is developed for the calculation of couling coefficients of waveguide grating devices. The coupling coefficients of several grating structures, such as rectangular, sinusoidal, triangle, and trapezoidal shapes, are determined by the RROM, and they are compared with those obtained by conventional methods of the ray-optics method (ROM) and the coupled mode method (CMM). In the case of rectangular gratings, the coupling coefficients is evaluated in detail by various depths and duty-cycles of the grating. We have found that the RROM gives more exact solutions for the coupling coefficients of even arbitrary shapes of diffractive waveguide grating devices than the other conventional methods.

• Advanced Industrial SCIence
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• v.2 no.4
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• pp.28-35
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• 2023

In this paper, a diffractive optical element was designed to create lighting patterns that satisfy the requirements of adaptive headlight systems for normal road mode, highway mode, and wet road mode, and this was rendered into a GDSII stream format file.To verify the effectiveness of the light distribution formed by the diffractive optical elements and the realization of white light, simulations based on Field Tracing and Ray Tracing were conducted, confirming the satisfaction of position and luminance requirements at the transformation beam measurement points. Based on this research, it is anticipated that the implementation of adaptive headlights would be possible, enabling the reproduction of luminance contrast and the creation of a simple-structured adaptive headlight system.

• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.157-163
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• 2024

We developed a 3-channel fiber laser with a common seed and a phase control system for laser beam combining through a diffractive optical element. Beam combining was performed by adjusting the angles of the beams incident on the diffractive optical elements, and the phase of each beam was controlled to maximize the intensity of the combined laser beam. The power of the 3-channel laser before passing through the diffractive optical elements is about 65 mW. The power of the combined beam varied between 2.9 mW and 48.3 mW depending on the phase change of each channel. Through phase control, the output of the combined beam can be maintained at 42 mW for more than 91.8% of the total time. It is expected that higher combining efficiency can be achieved by improving the transmittance of the diffractive optical elements and the performance of the phase control system.