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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Optics and Photonics
Journal Basic Information
Journal DOI :
Optical Society of Korea
Editor in Chief :
Volume & Issues
Volume 9, Issue 6 - Dec 1998
Volume 9, Issue 5 - Oct 1998
Volume 9, Issue 4 - Aug 1998
Volume 9, Issue 3 - Jun 1998
Volume 9, Issue 2 - Apr 1998
Volume 9, Issue 1 - Feb 1998
Selecting the target year
Measurement of the Photocount Distribution of the Quasi-thermal Light Source
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 129~133
The phtocount distributions of a quasi-thermal light source were measured by using the photoelectric counting method. The source was fabricated from the ground glass plate of 9
roughness illuminated by linearly polarized He-Ne laser beam. The coherence time of the quasi-thermal light changed from 31.4
according to the grain velocity of the ground glass plate. The photocount distribution showed the Bose-Einstein statistics for a long coherence time compared to the counting time interval, while the distribution approaches the Poisson distribution when the coherence time much shorter than the counting time.
Design of 4:1 I
zoom afocal telescope
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 134~141
A high performance afocal zoom telescope has been designed to operate in the 7.6
waveband for thermal imaging system. This IR zoom telescope is characterized by using of two movable optical element groups, variator and compensator, with mechanically compensated method and the positioning of these groups is controlled by means of a computerized program. The optical performance over the entire 4:1 zoom range and
9.36 degrees field of view is near diffraction limit while maintaining a constant F-number. The all refracting surfaces of this system except only one aspheric surface are spherical curvature and the material for the optical elements is selected Ge and ZnSe which is used for correction of chromatic aberration.
Diffraction Amplitude Distribution of Finite Gaussian Pupil with Residual Aberrations
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 142~145
It is shown that the optical system with Gaussian pupil e, diffraction amplitude distribution is not affected by the presence of residual aberrations. The case of spherical aberration is treated, as an example, and the complex diffraction amplitude distribution at the neighbourhood of the image point is described analytically by using a recurrence formula.
The research for the enhancement of depth of focus by elliptical polarization illumination(EPI)
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 146~150
To enhance the resolution and the depth of focus of the patterns whose size reaches the optical resolution limits, the various imaging methods are being tried. Generally in the linear polarization illumination methods, the contrast gap exists between TE mode TM mode according to the pattern direction. However, through the previous research, the elliptical polarization illumination(EPI) method was proposed to overcome this contrast gap. In this research, we investigated the optimal polarization condition to be able to enhance the depth of focus(DOF) for the optional mask which is containing the opposite direction patterns by applying the various polarization conditions including EPI. The DOF according to each polarization condition was obtained by ED-Tree(Exposure-Defocus Tree) for the given exposure dose and CD error boundaries. As the result, we can ascertain th effect of EPI for the enhancement of DOF in some condition of optical system.
Tunable fiber interference filter for sensors and communication system
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 151~155
A new Fabry-Perot tunable filter has been built with simple construction, which does not require any additional aligning and/or beam-confining components for the reduction of the diffraction loss. For this feature, one of the two fibers for the filter is processed to have a concave mirror whose curvature is the same as that of the wavefront of the Gaussian beam from the first fiber. After high reflection coatings, the two fibers are aligned to result in an FP filter whose bandwidth, free spectral range, and insertion loss is 1.47nm, 52nm, 5.6dB respectively.
Stress-Free Pyrex-Based Optical Waveguide for Planar Lightwave Circuits on Silicon Substrate
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 156~161
We developed aerosol flame deposition method and made stress-free Pyrex-based optical waveguide on silicon substrate using this method. Zr is doped to control the refractive index of Pyrex waveguide layers. The refractive index of the film changes from 1.460 to 1.475 as the content of Zr changes from 0 to 3 wt%. Er is doped to see the possibility of applying this Pyrex waveguide as PLC-type (Planar Lightwave Circuit) optical amplifier. The refractive index of the film changes from 1.460 to 1.465 as the content of Zr changes from 0 to 1 wt%. Light launching using a prism coupler to the fabricated waveguide showed good quality for application to PLC. The polarization dependence of refractive-index of the Pyrex film is measured to be less than
Preparation of low refractive index
optical thin films by ion beam assisted deposition
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 162~167
optical thin films of lower refractive indices than glass substrates were fabricated by the CF
ion beam assisted deposition method and the optical, structural and chemical properties of them were investigated. Refractive index of
films was varied from 1.455 to 1.394 by decreasing the anode voltage or from 1.462 to 1.430 by increasing the current density of end-Hall ion source. FT-IR and XPS analyses show that as the F concentration increases, the Si-O bond at
shifts to higher wavenumber, the OH bonds are reduced drastically, and the fluorine atoms at the air-film interface are desorbed out by reacting with
in the atmosphere.
thin films are amorphous by the XRD analysis and have the compressive stress below 0.3 GPa. As an application of
thin films a two-layer antireflection coating was fabricated using a
film as a low refractive index layer and a Si film as an absorbing one.
Measurement of the Nonlinear Optical Properties by use of the Far-Field Phase Modulation Method
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 168~174
We have measured nonlinear refractive index and nonlinear absorption coefficient of optical materials by using a far-field phase modulation technique. The phase variation of the probe beam in the nonlinear material is transformed into the spatial phase modulation in the far-field so that the spatial distribution of the optical intensity in conjunction with the computer simulation analysis can give the nonlinear optical constants. We have obtained the nonlinear refractive indices and nonlinear absorption coefficient of
by fitting the experimental values and numerical simulation analysis of far-field measurements. The nonlinear refractive indices of
were obtained as
esu, respectively at 616 nm, and the nonlinear absorption coefficient of BaF
cm/W at 308nm. These measured values were in good agreement with previous reports.
Growth of Nd:YAG single crystal by czochralski method and characteristics of laser generation
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 175~180
Nd:YAG single crystal widely used as solid state laser was grown by Czochralski method. <111> single crystal with 0.9at% of
was grown from the Czochralski furnace with a automatic diameter control system. The vertical temperature gradient in the liquid was the major factor that influence the crystal quality, and the crystal diameter was controlled by the home made computer program. The crystal boule with
ι100mm effective size was cut, polished, and antireflection coated. The optical evaluation such as absorption spectrum, fluorescence spectrum coincide with typical features of Nd:YAG single crystal. The laser rod was assembled into the CW laser generator with a Kr lamp. The maximum CW laser output was 70 W and the threshold power and efficiency was 1.3kW and 1.64% respectively.
Gain bandwidth characteristics of erbium-doped Fiber amplifiers for long-haul transmissions
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 181~185
Gain characteristic of concatenated erbium-doped fiber amplifiers(EDFA) are studied with a recirculating EDFA loop. For a non-flat gain EDFA, the 3 dB gain bandwidth was reduced to 6 nm after the 20th EDFA. However, for an optimized gain flattened EDFA, in a simple configuration, the 5 dB gain bandwidth was found to be 9nm, even after the 100th EDFA, corresponding to 8000km transmission. This results suggest that the simple optimized flat gain amplifier could be a good candidate for ultra-long distance wavelength division multiplexed transmissions.
Efficient Diode Pumped High Power Nd:YAG Laser with a Gold Coated Flow Tube
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 186~190
We fabricated a diode-side pumped high power Nd:YAG laser with a gold coated flow tube(diameter of 10mm) and three sets of 140W diode bar. The diameter of Nd:YAG rod was 6mm and its length was 130mm. We obtained 130W cw power from a linear resonator with an 11% output coupler, which corresponds to the slope efficiency of 43% and the optical efficiency of 31%. The measured beam quality factor(M
) reached about 85 which is fairly large due to the large size of the rod. Thermal lensing of the rod was measured to be 5.3-7.4D/
when the laser was operating.
Design and Fabrication of Holographic Collimating Lens for Semiconductor Laser
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 191~198
A method is described to produce off-axis hologram lenses without astigmatism for semiconductor lasers. We fabricated a holographic collimating lens by using dichromated gelatin film with high diffraction efficiency and without astigmatism which makes a collimated off-axis beam of semiconductor laser. We have designed the holographic collimating lens by applying the classical ray-tracing method to holographic diffraction. The elimination of astigmatism is obtained by choosing appropriate angles of recording and reconstruction beams. The hologram is recorded by use of
laser (488nm wavelength) and reconstructed by semiconductor laser(670nm wavelength). The physical parameters of recording and reconstruction angles, wavelength, and astigmatism are analytically calculated and experimentally confirmed.
Holographic recording system by combined use of rotational, angular, and spatial multiplexing method
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 199~204
To increase the storage density in hologram recording, a simple scheme to obtain rotational, angular and spatial multiplexing efficiently at the same time is proposed and experimented. Both rotational multiplexing and angular multiplexing are obtained by controlling the reference beam directly by use of a pair of wedge prisms, while spatial multiplexing is obtained by shifting the recording medium in the recording plane. It is possible to get both an acute-angle geometry, in which the angle between the signal and reference beams is less than 90
, and a 90
geometry, in which the angle is approximately 90
. In experiment, 180 holograms were multiplexed with an acute-angle geometry where a photopolymer was used for the recording medium, and 147 holograms with 90
geometry where a Fe-doped LiNbO
crystal was used. The proposed scheme makes it easy it easy to realize a practical holographic memory system by simplifying the control of three complex mechanical motions that are necessary for the three multiplexing techniques.
Evaluation of color CRT monitor by MTFA
Korean Journal of Optics and Photonics, volume 9, issue 3, 1998, Pages 205~211
The MTF(modulation transfer function) measuring system with a linear CCD(charge coupled-device) was constructed to cvaluate a color CRT(catode ray tube). The measured MTF values were corrected by considering the spectral response and the pixel sizes of CCD. The effects of a spot size, video bandwidth, pitch of shadow mask holes, display luminance, and ambient illumination on image quality were studied. The uniformity of resolution and the contrast Ioss by ambient light of the color CRT monitor were measured, and the results were analyzed by MTFA(modulation threshold area).