• Title/Summary/Keyword: space optics

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A Time-multiplexed 3d Display Using Steered Exit Pupils

  • Brar, Rajwinder Singh;Surman, Phil;Sexton, Ian;Hopf, Klaus
    • Journal of Information Display
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    • v.11 no.2
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    • pp.76-83
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    • 2010
  • This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

Simulations of Transmittance for the ITO/Ag/ITO Multiple Transparent Electrode Layers by 3 Dimensional FDTD Method (3차원 FDTD 방법에 의한 ITO/Ag/ITO 다층 투명전극막의 투과도 시뮬레이션)

  • Kim, Ki Rak;Cho, Eou Sik;Kwon, Sang Jik
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.3
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    • pp.88-92
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    • 2020
  • As a highly conductive and transparent electrode, the optical transmittances of ITO/Ag/ITO were simulated and compared with the experimental results. The simulations are based on the finite-difference time-domain (FDTD) method in solving linear Maxwell equations. In our simulations, the computation domain is set in the XZ-plane with 3D dimension, and a plane wave with variable wavelengths ranging from 250 nm to 850 nm is incident in the z-direction at normal incidence to the ITO/Ag/ITO film surrounded by free-air space. As the results through both simulations and experiments, it was shown that the thickness combinations by the ITO layers of about 40 nm and the Ag layer of about 10 nm could be most suitable conditions as a high conductive transparent electrode having the transmittance similar to that of a single ITO layer.

Optical bistability in the Fabry-Perot etalon which contains $As_2S_3$ space layer (비정질 $As_2S_3$를 중간층으로 Fabry-Perot 에탈론에서의 광쌍안정에 관한 연구)

  • 김강호;김석원;한성홍
    • Korean Journal of Optics and Photonics
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    • v.8 no.6
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    • pp.466-470
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    • 1997
  • We fabricated the asymmetric Fabry-Perot etalon which contains amorphous $As_2S_3$ as a spacer layer by using the method of optical multilayer coating and observed the optical bistability with the polarization. Optical thickness of the spacer layer is 2$\lambda$ at $Ar^+$ ($\lambda $=514.5 nm) laser wavelength. Optical bistability was observed at the intensities between 80~100 mW and the experiment shows us that the trends of bistable loop of the reflected and the transmitted lights are quite different depending on the state of polarization. This phenomena can be explained as the phase differences of each polarizations are different in the nonlinear Fabry-Perot etalon.

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Joint Transmission Slot Assignment, FSO Links Allocation and Power Control for Hybrid RF/FSO Wireless Mesh Networks

  • Zhao, Yan;Shi, Wenxiao;Shi, Hanyang;Liu, Wei;Wu, Pengxia
    • Current Optics and Photonics
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    • v.1 no.4
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    • pp.325-335
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    • 2017
  • Hybrid radio frequency/free space optical (RF/FSO) wireless mesh networks have attracted increasing attention for they can overcome the limitations of RF and FSO communications and significantly increase the throughput of wireless mesh networks (WMNs). In this article, a resource assignment optimization scheme is proposed for hybrid RF/FSO wireless mesh networks. The optimization framework is proposed for the objective of maximizing throughput of overall hybrid networks through joint transmission slot assignment, FSO links allocation and power control with the consideration of the fading nature of RF and FSO links. The scheme is formulated as an instance of mixed integer linear program (MILP) and the optimal solutions are provided using CPLEX and Gurobi optimizers. How to choose the appropriate optimizer is discussed by comparing their performance. Numerous simulations are done to demonstrate that the performance of our optimization scheme is much better than the current case of having the same topology.

All-fiber RGB Laser Light Source of Head-up Display System for Automobile Application

  • Lee, Jonggwan;Kim, Kyungwon;Son, Seong-Jin;Kim, Bok Hyeon;Yu, Nan Ei
    • Current Optics and Photonics
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    • v.4 no.3
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    • pp.221-228
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    • 2020
  • We developed an all-fiber RGB laser light source module for application in an automobile head-up display. It is based on laser diodes and an optical fiber combiner that substantially enhances the flexibility of configuration and stability against harsh working conditions for automobiles. We coupled 13 laser diodes with optical fibers and merged them into a single output with a beam combiner device. Red (R), green (G), and blue (B) laser sources were employed to produce primary colors that were mixed into a white light output. An optical output power of approximately 1.5 W was achieved, and the color balance of the output lights was assessed based on the CIE 1931 color space. The optical output power was shown to be stable for over 160 h within an optical fluctuation of less than 0.27%.

SENSITIVITY CALCULATIONS FOR THE COSMIC IR BACKGROUND OBSERVATIONS BY MIRIS (과학기술위성 3호 다목적 적외선 영상시스템 적외선 우주배경복사 관측 감도 계산)

  • Lee, Dae-Hui;Lee, Seong-Ho;Han, Won-Yong;Park, Jang-Hyeon;Nam, Uk-Won;Jin, Ho;Yuk, In-Su;Park, Yeong-Sik;Park, Seong-Jun;Lee, Hyeong-Mok;Park, Su-Jong;Matsumoto, Toshio;Cooray, Asantha
    • Publications of The Korean Astronomical Society
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    • v.22 no.4
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    • pp.177-181
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    • 2007
  • We present the sensitivity calculation results for observing the Cosmic Infrared Background (CIRB) by the Multi-purpose IR Imaging System (MIRIS), which will be launched in 2010 as a main payload of the Science and Technology Satellite 3 (STSAT-3). MIRIS will observe in I ($0.9{\sim}1.2um$) and H ($1.2{\sim}2.0um$) band with a $4{\times}4$ degree field of view to obtain the large scale structure (${\sim}3$ degree) of the CIRB. With the given specifications of the MIRIS, our sensitivity calculation results show that the MIRIS has a detection limit of ${\sim}9\;nW\;m^{-2}\;sr^{-1}$ (I band) and ${\sim}6\;nW\;m^{-2}\;sr^{-1}$ (H band), which is appropriate to observe the large scale structure of CIRB.

Four-channel Selective Photonic Microwave Filter Based on Optical Resonator Router (폴리머 광공진기 라우터 기반의 4채널 선택 포토닉 마이크로웨이브 대역통과 필터)

  • Kim, Gun-Duk;Eo, Yun-Sung;Lee, Sang-Shin
    • Korean Journal of Optics and Photonics
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    • v.19 no.3
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    • pp.242-245
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    • 2008
  • A four-channel selective microwave filter was demonstrated incorporating an optical resonator router, which is constructed by integrating a $1{\times}4$ space switch with an arrayed ring filters featuring different free spectral ranges. The center frequency of each channel was determined by the FSR of the corresponding ring resonator, and the four channels centered at 10 GHz, 16 GHz, 18 GHz and 20 GHz were individually selected to provide a bandpass filtering via the control voltage applied to the switched resonator.

UNVEILING COMPLEX OUTFLOW STRUCTURE OF UY Aur

  • PYO, TAE-SOO;HAYASHI, MASAHIKO;BECK, TRACY;DAVIS, CHRISTOPHER J.;TAKAMI, MICHIHIRO
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.109-112
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    • 2015
  • We present [$Fe\;{\small{II}}$] ${\lambda}1.257{\mu}m$ spectra toward the interacting binary UY Aur with 0".14 angular resolution, obtained with the Near infrared Integral Field Spectrograph (NIFS) combined with the adaptive optics system Altair of the GEMINI observatory. In the [$Fe\;{\small{II}}$] emission, UY Aur A (primary) is brighter than UY Aur B (secondary). The blueshifted and redshifted emission between the primary and secondary show a complicated structure. The radial velocities of the [$Fe\;{\small{II}}$] emission features are similar for UY Aur A and B: ${\sim}-100km\;s^{-1}$ and ${\sim}+130km\;s^{-1}$ for the blueshifted and redshifted components, respectively. Considering the morphologies of the [$Fe\;{\small{II}}$] emissions and bipolar outflow context, we concluded that UY Aur A drives fast and widely opening outflows with an opening angle of ${\sim}90^{\circ}$ while UY Aur B has micro collimated jets.

HIGH-RESOLUTION NEAR-INFRARED SPECTRA OF NEARBY QUASARS

  • Le, Huynh Anh Nguyen;Pak, Soojong;Im, Myungshin;Ho, LuisC.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.91-91
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    • 2012
  • We present high-resolution near-infrared host galaxy spectra of low-z quasars, PG0844+349 (z=0.064), PG1226+023 (z=0.158), and PG1426+015 (z=0.086). The observation was done by using the near-IR high resolution echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. The full width at half maximum of the point spread function was about 0.3 arcsec by using an Adaptive Optics system, which can effectively resolve the quasar spectra from the host galaxy spectra. The signal-to-noise ratios are increased by the total exposure time up to several hours per targets and the development of data reduction method. We compare our results to the stellar spectra library and sample spectra from Dasyra et al. (2007) and Watson et al. (2008). The identified spectral lines will be used to study the physical mechanism of quasars, and the velocity dispersions of the stars in the bulge of the host galaxy.

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Three-dimensional relative-distance measurement by use of the phase-shifting digital holography (위상천이 디지털 홀로그래피를 이용한 3차원 상대 거리 측정)

  • Kim, Hyun;Lee, Yeon-H.
    • Korean Journal of Optics and Photonics
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    • v.14 no.2
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    • pp.200-207
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    • 2003
  • In this paper we present a new method of measuring the relative distance of two point objects in three-dimensional space by using phase-shifting digital holography. In our system the reference beam of a spherical wave is used instead of a plane wave. The system is computer simulated and built on an optical table for experiments. It is shown from computer simulations and experiments that the relative distance can be measured without the exact information on the reference beam used in the hologram record. It is shown from experiments that the relative distance between two point objects separated by 0.5 cm in the distance of about 300 cm from the CCD can be measured with an error less than 10%.