• Title/Summary/Keyword: Blue laser diode

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ZnO films grown on GaN/sapphire substrates by pulsed laser deposition

  • Suh, Joo-Young;Song, Hoo-Young;Shin, Myoung-Jun;Park, Young-Jin;Kim, Eun-Kyu
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.207-207
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    • 2010
  • Both ZnO and GaN have excellent physical properties in optoelectronic devices such as blue light emitting diode (LED), blue laser diode (LD), and ultra-violet (UV) detector. The ZnO/GaN heterostructure, which has a potential to achieve the cost efficient LED technology, has been fabricated by using radio frequency (RF) sputtering, pyrolysis, metal organic chemical vapor deposition (MOCVD), direct current (DC) arc plasmatron, and pulsed laser deposition (PLD) methods. Among them, the PLD system has a benefit to control the composition ratio of the grown film from the mixture target. A 500-nm-thick ZnO film was grown by PLD technique on c-plane GaN/sapphire substrates. The post annealing process was executed at some varied temperature between from $300^{\circ}C$ to $900^{\circ}C$. The morphology and crystal structural properties obtained by using atomic force microscope (AFM) and x-ray diffraction (XRD) showed that the crystal quality of ZnO thin films can be improved as increasing the annealing temperature. We will discuss the post-treatment effect on film quality (uniformity and reliability) of ZnO/GaN heterostructures.

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Evaluation of Static Error Signal for Super Slim Optical Pick-up (초소형 광 픽업의 정적 오차 신호 검출)

  • Kang, S.M.;Cho, E.H.;Sohn, J.S.;Kim, W.C.;Park, N.C.;Park, Y.P.
    • Transactions of the Society of Information Storage Systems
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    • v.1 no.2
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    • pp.115-120
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    • 2005
  • As a popularity of a portable digital device such as a cellular phone, a digital camera and a MP3 player is spreading, the demand of the mobile storage device increases rapidly. A bluray technology using 405nm laser diode and objective lens having high NA(Numerical Aperture), 0.85, satisfies a miniaturization and a high capacity which are the requirements of the portable device. To develop SFFOP(small form factor optical pickup), it is prerequisite to minimize the number of optical components and establish evaluation and assembly method of micro optical pickup system as well as mass production method of micro optical component. To minimize optical elements of optical pickup, there have been many researches to use P-HOE(Polarized Holographic Optical Element) due to its extremely small size and versatile function. However, P-HOE is handled and assembled very accurately in SFFOP. In this paper, static error signal detection method is developed for an alignment of P-HOE in SFFOP. Using developed static error signal detection method, P-HOE can be aligned very accurately with real time result of static error signals of pickup such as FES(focusing error signal) and TES(Tracking Error Signal). The developed static error signal detection method is verified by the evaluation of commercialized DVD Pickup. And finally. developed static error signal detection method is applied for the assembly of P-HOE in SFFOP system satisfies specification of BD(Blu-ray Disk).

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Properties of Y3Al5O12:Ce3+,Pr3+ Single Crystal for White Laser Lightings (백색 레이저 조명용 Y3Al5O12:Ce3+,Pr3+ 단결정 특성)

  • Kang, Taewook;Lim, Seokgyu;Kim, Jongsu;Lee, Bong
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.4
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    • pp.37-41
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    • 2018
  • $Y_3A_{l5}O_{12}:Ce^{3+},Pr^{3+}$ single crystal phosphor was prepared by floating zone method. single crystal was confirmed to have a Ia-3d (230) space group of cubic structure and showed regular morphology. The optical properties, single crystal exhibited a emission band from green, yellow wide wavelength and 610nm, 640nm red wavelength vicinity. The luminance maintenance rate was decreased by phonon with increasing temperature, but high luminance is maintained more than powder phosphor. In addition, $Y_3A_{l5}O_{12}:Ce^{3+},Pr^{3+}$ single crystal phosphor was applied to a high power blue laser diode, we implemented high power white laser lightings. and it was confirmed that thermal properties over time, due to the effective heat transfer of complete crystal structure. We confirmed that excellent radiant heat properties than powder phosphor was applied to a high power white laser diode.

Microstructure Characterization of Ternary ZnSSe/GaAs Epilayer Grown by MBE (MBE로 성장시킨 3원계 ZnSSe/GaAs 에피층의 미세구조 특성)

  • Lee, Hwack-Joo;Ryu, Hyun;Park, Hae-Sung;Kim, Tae-Il
    • Applied Microscopy
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    • v.25 no.3
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    • pp.75-81
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    • 1995
  • The microstructural characterization of ternary $ZnS_{x}Se_{1-x}$(x=0.085) on GaAs(001) substrate grown up to $2{\mu}m\;at\;300^{\circ}C$ by molecular beam epitaxy(MBE) which has a single growth chamber was investigated by high resolution transmission electron microscope (HRTEM) working at 300 kV with point resolution of 0.18nm. The interface in the ZnSSe/GaAs specimen maintains a pseudomorphism with the substrate, but the epilayer has high density of stacking faults and moire fringes. The pits which had formed along <111> direction were found at the interface of ZnSSe/GaAs. The pits were responsible for producing defects in both epilayer and substrate. The wavy interface which has the difference of 15nm in height was found to maintain the pseudomorphism with the substrate and no stacking faults were found around the interface. However there exists faint and fine moire fringes in the epilayer near interface.

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The Three-wavelength PR3+:YLF Laser at 604 nm 607 nm and 640 nm with Fabry-Perot Etalon

  • Jin, Long;Jin, Yu-Shi;Dong, Yuan;Li, Qing-Song;Yu, Yong-Ji;Li, Shu-Tao;Jin, Guang-Yong
    • Current Optics and Photonics
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    • v.2 no.5
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    • pp.448-452
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    • 2018
  • A three-wavelength $Pr^{3+}:YLF$ laser at 604 nm, 607 nm and 640 nm simultaneously output by Fabry-Perot (F-P) etalon has been obtained. A 444 nm blue laser diode is used for pumping the $Pr^{3+}:YLF$ crystal, and a 0.1 mm F-P etalon is inserted in the resonator to select wavelength. The theoretical model of three-wavelength $Pr^{3+}:YLF$ laser is established, by adjusting the tilt angle of the etalon, the transmittances of the different wavelengths can be controlled, and the threshold values can be made to equalize by controlling the loss among different wavelengths. In the experiment, when the tilt angle of etalon is $9^{\circ}$ and the optimized length of resonator is 48 mm, the total output power of 25 mW at the three-wavelength is achieved at incident pump power of 7.5 W.