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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Optics and Photonics
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Journal DOI :
Optical Society of Korea
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Volume & Issues
Volume 1, Issue 2 - Sep 1990
Volume 1, Issue 1 - Mar 1990
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Two-Photon-Resonant Three-Photon Ionization of Na Atom
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 1~6
We studied two-photon-resonant three-photon ionization processes via 4D[channel #1] and 5S(channel #2] intermediate state of Na atom in a quartz ionization cell. For each channel. the bandwidth of ionization spectrum increased linearly with laser intensity and the ionization signal followed J3 dependence at low intensity. Compared with channel # 1 . ionization signal of channel #2 was enhanced by a factor of 20 - 25. The measured AC Stark shift factor of 3S - 4I) transition was
Laser Intensity Dependence in Resonant Multiphoton Ionization of Hg Atoms
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 7~11
Resonant multi photon ionization (RMPD of Hg atoms is studied by focusing a high-power laser into the ionization cell. The intermediate resonant state is taken as
with the 4-photon resonance wavelength of 560.7 nm. The ionization signal is measured as Hg vapor pressure (0.1-3.0 Torr), laser intensity
, and laser wavelength (559-569 nm) vary. AC Stark shift and line broadening of the resonant state
are observed and the shift factor is measured to be
. It is also observed that the ionization signal increases as the Hg vapor pressure increases up to a certain value of pressure, however, if the pressure further increases, the signal decreases. The order of non-linearity, which discribes the laser intensity dependence of ionization rate, is measured to be 3 at the resonance, and compared with the theoretical results.esults.
Measurement of 3-D Deformation by Using Holospeckle Interferometry
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 12~15
Holospeckle interferometry, the combined technique of holographic interferometry and speckle photography, was applied to the measurement of 3-D contact deformation created by an indentor. This new tech
nique makes possible to measure both in-plane and out-of-plane displacements from one photographic plate. In this study, the optical system based on image holography was set up. In order to enhance the size and the contrast of the speckle, a proper magnification and a low reference beam ratio was used as compared with the conventional holographic interferometry technique. This system shows the magnified and clear holographic interference fringe as well as Young's fringe patterns.tterns.
Polarization Properties of Signals in
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 16~21
The accurate polarization state of the light inside BSO crystal was calculated with consideration of optical activity. By solving Maxwell's equations, the general form of the polarization matrix for any direction of the electric field was obtained. Examples of output polarization states in BSO crystals were also calculated, and their properties were discussed.
Cavity-Length Detuning Characteristics of a Hybridly Mode-Locked Ultrashort Pulse Dye Laser
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 22~27
The cavity-length detuning characteristics of the hybridly mode-locked dye laser have been studied with a collinear autocorrelator. In the optimum condition, the pulse width is 0.65 ps about three times as short as that of the synchronously mode-locked dye laser. As the cavity length is increased, the pulse width becomes broader than that at the optimum cavity length because of the effect of spontaneous emission. Also, the spectrum width becomes broad, therefore the time bandwidth product (
) is increased. The peak power of autocorrelation is maximum at
longer than the optimum cavity length. On the other hand, as the cavity length is decreased, the pulse width becomes broader and the satellite pulses appear because of the gain recovery. Also the spectrum width becomes narrower than that at the optimum cavity length. In particular, at the mismatched cavity length the center of the lasing spectrum moves to shorter wavelengths. ngths.
Development of the Discharge Heated Copper Vapor Laser
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 28~32
We have constructed and operated a discharge heated copper vapor laser which generated green (510.6 nm) and yellow (578.2 nm) light. The plasma tube was made of high purity (99.8%) alumina tube which has an inner diameter 25 mm and a length 106 cm. The electrodes, made of molybdenum sheet, were separated 108 cm apart. The laser gave an average power of 10 W at repetition rate of 5 kHz, charging voltage of 10 kV, Ne buffer gas pressure of 40 mbar, and the laser tube temperature of
Theoretical Analysis of Buffer Gas Effects of a Discharge Excited KrF Laser
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 33~39
By developing a computer simulation code for discharge excited KrF excimer laser, we analyzed mainly the effects of buffer gas for the
relaxation. and the absorption of the laser radiation. The
formation efficiency were found to be 7.5%, 19% and the
relaxation kinetic reactions were found to be 45%, 30% at the charging voltage of 30 KV and He. Ne buffer gas. respectively. But the absorption of the 248 nm laser radiation were less than 10% by the buffer gas.er gas.
Pulse Compression by the Nonlinear Silicon Fabry-Perot Interferometer
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 40~45
Optical pulse compression in a high finesse nonlinear Fahry-Perot interferometer made hy a silicon is ohserved. The optical pulse compression and moclul,ltion in a such nonlinear Fabry-Perot interferometer is due to the refractive index change of the silicon hy absorbing the incicknt pulse and generating electron-hole pairs. The pulse is compressed to liS of width of the IIlcicient pulse. And the experimental results are consistent with the results of computer simulation.lation.
Contact Microscopy by Using Soft X-ray Radiation from Iodine Laser Produced Plasma
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 46~51
Laser plasma was generated by a 1GW iodine photodissociation laser (
, E=12.7J) whose output beam was focused on a molybdenum target surface. The experiment was conducted in a vacuum chamber under 1D-sTorr and several tens of laser shooting were necessary for sufficient exposure for the PBS resist of 111m thickness. Aluminium was coated on the top of the resist by 0.1
thickness which acts as an X-ray filter to cut off the visible and the ultraviolet lights. A bio-specimen was put directly on the aluminium coated resist and located at a distance of 3 cm from the X-ray source. The replicas of a steel mesh, spider's web. and a red blood cell were obtained by this technique and were observed by Nomarski microscope and SEM. The limitation of its resolution is determined by the X-ray source size and Fresnel diffraction effect, and its theoretical prediction is well matched with the experimental results. In this experiment, a resolution better than 0.1
could be obtained. ained.
Lifetime and Anisotropy Measurements of DODCI in the excited state by TCSPC
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 52~57
Employing a picosecond laser and fast electronics. we developed a time -correlated single photon counting (TCSPC) system by which ltuninescence lifetimes can be measured in the subnanosecond to microsecond scale. We also studied non-radiative decay dynamics and rotational motion of DODC! laser dye in solution using this system. ystem.
Determination of Flow Direction by Using an Acousto-Optic Modulator
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 58~64
The flow direction in a glass tube is measured by using a forward scattering dual beam laser Doppler velo
cimeter with an acousto-optic modulator. We can determine the flow direction by measuring the shifted Doppler frequency which is dependent on the order of modulation of the laser beam and the fluid flow direction. Also. an electronic amplification circuit which has a bandwidth of 0 . 300 MHz and a gain of 38 dB is designed and fabricated to amplify the high frequency signal.signal.
Fabrication and Characteristics of Mather Type Plasma Focus System
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 65~72
Mather type plasma focus system is designed and fabricated, and its electrical behaviors and the ,~haracteristics of the plasma are investigated. The discharge CUlTent is measured with a Rogowski coil, and the external resistance and inductance of the system are found to be
respectively from the measured voltage signals and current signals, and discharge inductance, magnetic, and mechanical energy are calculated. 'i'he speed of the plasma current sheath in the acceleration phase is found to vary as
and its value is about is 106 cm/sec. The electron temperature in the plasma is determined from the measurement of the X-ray transmittance with the number of X-ray filters and its value is found to be about I keY. The size of plasma, measured using X-ray pin-hole camera, is about 17 (dia.) x 30 (length)mm2. h)mm2.
Analysis of Surface and Thin Films Using Spectroscopic Ellipsometry
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 73~86
The technique of Spectroscopic Ellipsometry (SE) has been examined with emphasis on its inherent sensitivity to the existence of thin films or surface equivalents. A brief review of related theories like the Fresnel reflection coefficients, the effect of a multilayer upon reflectivities, together with the validity of the effective medium theory and the modelling procedure, is followed by a short description of the experimental setup of a rotating polarizer type SE as well as the necessful expressions which lead to tan and cos. Out of its numerous, successful applications, a few are exampled to convince a reader that SE can be applied to a variety of research fields related to surface, interface and thin films. Specifically, those are adsorption and/or desorption on metals or semiconductors, oxidation process, formation of passivation layers on an electrode, thickness determination, interface between semiconductor and its oxide, semiconductor heterojunctions, surface microroughness, void distribution of dielectric, optical thin films, depth profile of multilayered samples, in-situ or in-vitro characterization of a solid surface immersed in electrolyte during electrochemical, chemical, or biological treatments, and so on. It is expected that the potential capability of SE will be widely utilized in a very near future, taking advantage of its sensitivity to thin films or surface equivalents, and its nondestructive, nonperturbing characteristics.
Spectroscopic Applications of Ultrashort Pulse Lasers
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 87~97
With the recent advent of various ultrashort pulse lasers, time-resolved laser spectroscopic techniques have been widely recognized as versatile tools to study ultrafast phenomena in many research areas. These techniques are currently being employed not only to study atomic and molecular physics but to characterize the excited state or the carrier dynamics on surfaces of semiconductors, metals and thin layer materials. Also the sweetching speed measurement of ultrafast electro-optic devices using ultrashort laser pulses becomes important in high-speed electronics. Here, some principles of spectroscopic techniques with ps or fs lasers and their applications are summarized briefly.
Material Processing by Laser
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 98~106
Lasers are used increasingly for specialized engineering applications such as drilling, profile cutting, welding and surface heat-treatment(hardening, alloying, annealing0 of metals and non-metals. The most important characteristics of lasers used for these materials-processing applications are reviewed, with special emphasis on the importance of the controlled heating process. In addition to these processes, some optical devices and supplementary equipment used in laser processing are introduced. Finally, some examples shows the wide variety of laser capability for substitution of traditional materials processing.
Korean Journal of Optics and Photonics, volume 1, issue 1, 1990, Pages 107~113
Characteristics and applications of three major types of lasers are discussed. They are chemical-metabolic, thermal destructive, and nonthermal mechanical lasers. The thermal destructive lasers (
, Argon, and Nd:YAG) are especially explained in detail with regard to energy density, wavelength, fluence, stage of thermal destruction, and advantages of laser surgery. Excimer and Q-swiched lasers are discussed as nonthermal mechanical ones. Delivery system, optical fiber and articulated arm, is also discussed. Finally, recent advancements of medical laser are included in the conclusion.