Go to the main menu
Skip to content
Go to bottom
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 11, Issue 6 - Dec 2000
Volume 11, Issue 5 - Oct 2000
Volume 11, Issue 4 - Aug 2000
Volume 11, Issue 3 - Jun 2000
Volume 11, Issue 2 - Apr 2000
Volume 11, Issue 1 - Feb 2000
Selecting the target year
Atomic motion and spatial distribution of 87Rb by Coordinate-dependent asymmetry radiation force in MOT
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 221~226
We observed the spatial distributions of atom in a magneto-optical trap. These distributions include sphere, stick, ring, ring with core, sphere-sphere, sphere-ring etc. Coordinate-dependent asymmetry radiation force (CDARF) that arises due to laser beams misalignment and transverse profile of the laser beams is exerted on atoms, and the shape of trapped cloud is changed with the misalignment parameter. We use equations of motion that takes into account the Zeeman sublevels of the 87Rb atom, magnitude and direction of magnetic field, polarization of trapping lasers, and transverse profile of the laser beams. A theoretical analysis of the equation of motion for the trapped atom explained all the experimental observations.
Collimation of cesium atomic beam using laser light pressure
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 227~231
Thermal cesium atomic beam was collimated by transversely cooling of atoms, for which circularly polarized (
polarized) laser light was illuminated to the atomic beam from two perpendicular directions. As a result, the temperature corresponding to the transverse velocity component could be decreased from 430 mK to 60 11K. In addition, the spatial atomic distribution was observed according to the power difference of the two laser beams and the magnetic field applied, and the result was qualitatively coincided with the calculation result by the Doppler cooling theory. heory.
Collimation testing of a white light beam and measurement of chromatic aberration of a lens by using vernier Moire fringe patterns
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 232~238
The new collimation testing technique of a white light beam using vernier Moire fringes of two line or circular gratings with different pitches is presented. We can visually measure the defocusing (
), the divergence angle (
), and the longitudinal chromatic aberration
of a collimating lens by using the technique. For example, we obtained
= 21.9 mm and
for a testing lens with the focallengthf = 120.0 mm and F-number of F/2.4. The longitudinal chromatic aberration
of another testing lens withf = 65.0 mm, F/1.6, and the Abbe number V = 64.1 for the incident wavelengths of
is easily measured by same technique. It is found that the measured value
is well agreed with
obtained by the autofocus method.
Optical system design for compact digital still camera using diffractive optical elements
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 239~245
In this paper, the fundamental properties of diffractive optical element were investigated. Also, this work deals with theoretical approaches for achromatization in DOE's optical system based on thin lens theory. It is found that achromatization could be satisfied by one hybrid lens only, which is composed of a diffractive and a refractive element. In order to have compact optical system, we used the tele-photo type lens composed of a positive and a negative power elements instead of retro-focus lens. From the Gaussian brackets and Seidel aberration theory, the initial design was numerically obtained. The aberration properties of an initial design was aplanat and flat field. In order to correct the chromatic aberrations, refractive and diffractive elements were used on front element. This hybrid lens is also useful for correction of higher order aberrations. Compared to conventional design composed of refractive lenses only, this approach dramatically improved the compactness of the optical system. Finally, residual aberration balancing results in a lens with focal length of 3.89 mm and overall length of 5.19 mm, which has enough performance over an f-number of 4.0. Also, it is expected to fulfill all the requirements of a digital still camera lens. This optical system is superior to the current refractive lens system in the number of elements, weight, and aberration properties. rties.
Null lens design for testing of elliptical surface
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 246~249
The null lens is designed for testing the elliptical (conic constant>O) mirror which is the third mirror of the off-axis Three Mirror Anastigmat (TMA) designed as a high resolution camera for remote sensing. The mixed type design is proposed as a new design type which has a small annular flat mirror, but has as twice sensitivity as the autostigmatic type design. It is also shown that the null lens of the Mixed type is better than that of the autostigmatic type in terms of the sensitivity of the wavefront distortion which is given as the magnitude of optical path difference with respect to the change of each surface parameters such as the radius of curvature, thickness of lenses and tested mirror.
Measurement of angular velocity using the self-mixing effect of semiconductor laser
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 250~254
We have constructed laser Doppler velocimetry system using self-mixing effect with a semiconductor laser. This technology is based on the frequency mixing phenomena which occurs when light scattered back from the moving object into the laser cavity interferes with light inside the laser. We have compared the value of Doppler shifted frequency with the velocity variation of the wheel. Frequency dependence on the angle between the moving direction of rotating aluminum wheel and the incident beam also have been proved. As an illustration of the performance of the velocimeter, velocity measurements of a rotating disk are described. Doppler signal shows a good linear relationship with velocity of rotating disk.
The influence of preparation condition on optical property of sol-gel derived hybrid organic-inorganic silica glass thin films
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 255~260
We report that the crack-free organic-inorganic hybrid silica thin films were fabricated by sol-gel process using organometallic compounds as a precursor and that we have established very reproducible fabrication condition with systematic investigation of thickness and refractive index variations for various control parameters, such as, coating type, coating speed, chemical composition, prebake and postbake temperature. Additionally, we measured and compared the change of optical property with the UV exposure dose for three different kinds of photoinitiators. Furthermore, the fabrication of Ix4 MMI optical power splitter using the sol-gel thin film provides the possibility of various applications to the optical waveguide devices. vices.
Fabrication of neutral density (ND) filter using silver halide photo film
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 261~264
Continuous ND filters are fabricated on the silver halide photoplates. These filters enable us to get intensity modulated laser beam. Two kinds of continuous ND filters are fabricated. Optical density of one filter is increased radically and that of the other is decreased. In order to get a filter having desirable optical density, a mask which has reversed optical density has to be made. made.
Numerical analysis on the effects of external light injection seeding in a gain-switched DFB semiconductor laser
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 265~270
We investigate the effects of the power and wavelength of externally injection seeded light on timing jitter and pulse width in a gain-switched
DFB semiconductor laser by numerical simulation based on the transmission line laser model. As external seeding power increases, the timing jitter decreases and the pulse width increases. The lowest timing jitter is observed when the seed wavelength is aligned with the chirped spectrum center. By external seeding, we can decrease the timing jitter up to 1/2.7 without noticeable increase in pulse width. Our simulation results reasonably well agree with our sampled experiment and the other published papers. This proves the validity of our model to analyze a system based on a semiconductor laser. laser.
Fabrication and analysis of
spot-size-converter integrated laser diodes
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 271~278
We have fabricated and analyzed the lasing characteristics of 1.3
Spot-Size-Converter (SSC) integrated Fabry-Perot (FP) laser diodes, which are very promising light sources for optical subscriber networks. SSC-LDs has been developed by BIB (buttjoint-built-in) coupling and selective MOVPE growth. High-performances were achieved such as the slope efficiency from the SSC facet of 0.23-0.32 mW/mA, the full-width at the half maximum of the far-field pattern (FFP) of 9.5
, the alignment tolerances of
within the extra-coupling loss of 1 dB for the vertical and parallel directions, respectively. These experimental results were compared to theoretical ones in order to clarify the operational problems and give a good design direction of the fabricated SSC-LDs. It was revealed that an asymmetric output power from the facets, an irrelevancy of FFP and the waveguide structure around SSC facet region, and a poor temperature characteristics were originated from the scattering in the BIB and SSC sections and SHB effect in the active section for the first time.t time.
A Study on configuration of a laser resonator with high alignment stability
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 279~288
The variations of output energy due to tilt output coupler for different types of pulsed Nd:YAG laser resonators were compared by measuring FWHM (full width at half maximum) which means the width of angle displacement where maximum output energy decreases to half value. We proposed a new configuration of pulsed solid-state laser resonator which had high FWHM for tilting of output coupler and which was little sensitive for tilting of rear optics. We proved that our laser resonator had high alignment stability using ABeD ray matrix method because the ray matrix of such a resonator corresponded to unit matrix. atrix.
Output characteristics of diode-laser-pumped Tm:YAG laser
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 289~293
Diode-laser-pumped Tm:YAG laser of wavelength
has been manufactured and its excitation efficiency and output characteristics have been investigated. The excitation efficiency was varied from 66 to 68% with respect to the pump power, yielding pump power absorption of 87-89%. The output power was sensitively varied with the temperature of Tm:YAG rod. When the concave output coupler with a focal length of 25 mm and a transmittance of 3% was used, the maximum output power reached up to 1.2 W. The slope and optical efficiency of this Tm: YAG laser was 29% and 20% at
Output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser
Korean Journal of Optics and Photonics, volume 11, issue 4, 2000, Pages 294~298
The output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser were investigated. Nd:S-VAP is suitable for a microchip laser medium, which has a low threshold property because of a very high value of the stimulated emission cross-section and lifetime product. The threshold energy measured was 81 J.ll. The second harmonic output energy measured was
at a pump energy of
. We described for intracavity frequency doubling by using theoretical calculations. Q-switched second harmonic energy measured was
per pulse with a pulse-width of 26 ns. at a pump energy of 2 mJ and an
of 1.47 represented a good beam quality. ality.