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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 10, Issue 6 - Dec 1999
Volume 10, Issue 5 - Oct 1999
Volume 10, Issue 4 - Aug 1999
Volume 10, Issue 3 - Jun 1999
Volume 10, Issue 2 - Apr 1999
Volume 10, Issue 1 - Feb 1999
Selecting the target year
Asymmetry of the 1.54
forward and backward raman gain in methane
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 89~94
forward and backward stimulated Raman scattering (SRS) have been studied in CH
pumped by 1.06
Nd:YAG laser. The forward and backward SRS output energy in a single pass were measured at dufferent CH
pressures. Under steady state conditions, the pump input threshold energies and Raman gains in forward and backward directions were for Raman conversion at various CH
pressures for a tight focusing geometry. The forward and backward slope efficiency for Raman conversion were 18% and 34% respectively. The pump input threshold energy of the backward SRS was lower than that of the forward. In backward SRS, the experimental input laser threshold and Raman gain values were in good agreement with the calculated values at different pressures of CH
. The retio of the backward to the forward SRS gain was appoximately 1.4 times above 1200 psi. We obtained that the backward Raman gain coefficient was 0.32 cm/GW, and the forward Raman gain coefficient 0.23cm/GW at 1400 psi. Asymmetry of the forward and backward Raman gain is caused by the interaction between different pump intensities of each direction duting the amplification of the Stokers. The backward Raman gain is proportional to the average pump intensity. However, the forward SRS output grows by depleting the local pump intensity.
Stimulated Raman scattering at 1.54
and Brillouin scattering at 1.06
under 5 Hz repetition rate
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 95~101
We have studied the 1.54
forward and backward stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SRS) for various
pressures by 1.06
Q-switched Nd:YAG laser pumping under a repetition rate of Hz in single pass. We obtained that the output of backward SRS was more efficient than that of the forward SRS. The output energy and conversion efficiency of forward and backward SRS were higher than those of SBS since SRS is a steady state, but SBS is a transient state. In a
gas uncirculating system, the output energy of the backward SRS and SBS were reduced the about 47% due to a thermal heating of
medium in a focusing region for a repetition rate of 5 Hz. But, the output energy of forward SRS was slightly enhanced by about 8.5% due to the increase of the undepleted pump beam in the backward SRS generation. Inthe Raman half resonator using a dichromatic focusing lens, the conversion efficiency of SRS was more than 37% for a input pump laser energy of 40 mJ.
Inhomogeneous amplitude modulation effects on the MTF of binocular objective
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 102~106
In this study, inhomogeneous amplitude modulation effects on the imaging performance a lens system are expermentally investigated by measuring the diffraction OTF. The lens under the test is a binocular objective made in Korea. Inhomogeneous amplitude modulation is carried out by positioning the modulator cross contacted to the lens under test which is illuminated by collimated light beam. The aberration characteristics of the lens under test are examined by caculating the ray-fan through finite ray tracing. The MTFs of the lens illuminated by the homogeneous and inhomogeneous light beam are measured on the Gaussian image plane and compared with one another.
Design and fabrication of a holographic scanner using the ray tracing method
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 107~113
Low-aberration holographic scanners that eliminate the need for lenses and mirrors promise to greatly reduce the cost of laser printers and image scanners. In this study, a holographic optical element that can simultaneously scan and focus a laser beam is designed with analytic ray tracing method. An analytic and experimental work is conducted in which we investigated the hologram structure and hologon configuration for linear aberration-free scanning. For a prototype scanner, a He-Ne laser is used to manufacture and reconstruct the hologram, and the measured bow is about
and spot size(half-intensity beamwidth) in under 100
for a 300 mm scan length without using a correcting lens or mirror. The diffraction efficiency is about 55
5%, which is acceptably flat. The experimentally measured results agrees with the computed values. From this fact, we can conclude that the computed results using ray tracing method are practical and useful values, and have a potential for use in high resolution laser printers.
Effects of system imperfections on optical interaction-free measurements
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 114~119
In an interation-free measurement system with the polarization-based Mach-Zehnder interferometer structure, effects of two system imperfections, i.e., the system loss and the low quantum efficiency of photon detectors, on the system perfomance are analyzed, Although both the two system imperfections limit the maximal defection efficiency that can be achievable, we show that the quantum efficiency of photon detectors is less important when the system loss becomes small. In addition, for given system losses and quantum efficiencies, we derive the maximal detection efficiencies that can be achievable.
Design and fabrication of holographic combiner for automotive head-up display
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 120~127
We discussed two main types-conformal and non-conformal (powered) - of holographic combiner. A theoretical model based on the Kogelnik's coupled wave theory was used to illustrate bandwidth and efficiency properties. Also we showed numerical values for the aberrations that are induced by a wavelength shift from construction to reconstruction and found optimum coordinates to reduce the chrolatic aberation of construction beams using aberration balancing techniques. The holographic combiner manufactured in conformal type with 60
incidence angle at 514.5 nm had narrow angular bandwidth (FWHM) of 4.1" and spectral bandwidth of 11.4 nm, while non-conformal one with 50
incidence angle at 514.5 nm showed spectral and angular bandwidth of 10.7 nm and 5.5
A study on resolution analysis of incoherent trigangular holography
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 128~137
We found the point-spread function (PSF) including the recording and reconstruction systems of the modified triangular interferometer. We also derived the resolutions of the modified and Cochran's triangular interferometers, then the resolutions of both systems for amplification factor, wavelength, and hologram size were found and analyzed. Also, to demonstrate the feasibility of incoherent holography, the formation of an incoherent hologram using a mercury lamp and its optical reconstruction were presented.
Effect of misconvergence on resolution of color CRT monitor
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 138~145
By varying the beam current of a color CRT(cathode ray tube) monitor, the misconvergence, spot size, display luminance, and chromaticity coordinate of a white pattern were measured at 4 screen positions. The misconvergence was measured with a linear CCD (charge coupled-device). The resolution was obtained by using SQRI (square root integral) method. The misconvergence of a color monitor was not influenced by the beam current but by the screen position. The misconvergence on a screen perimeter caused the resolution to decrease.
Harmonic mode locking of 'Figure-of-Eight' fiber soliton laser using regenerative phase modulation
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 146~151
We demonstrated a harmonic mode locking scheme that used regeneratie phase modulation to get a high and stable repetition rate in a figure-of-eight fiber soliton laser. From the detected beat spectra of the laser output, a sinusoidal clock freguency tone of 400 MHz, the 96th harmonics of the fundamental mode locking frequency, was extracted with a high Q filter and was used to drive the phase modulator, resulting in stable output of soliton pulse train synchronized with the modulation signal. Generated soliton pulses had FWHM pulsewidth of 930 fs and 3.1 nm linewidth, yielding pulsewidth-bandwidth product of 0.359 that was close to the transform limit. As the modulation frequency always followed the beat frequency of laser modes, stable harmonic mode locking was achieved without the adjustment of the cavity length, which has been commonly required in actively mode-locked lasers.
Continuous pulse width variable quenched dye laser
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 152~156
We have developed the pulse-width variable Quenched Dye Laser (QDL). QDL consisted of the dye cell of 5 mm length containing a
[mol/l] solution of Rhodamine 6G and the cylindrical lens focal length of 150 mm and quenching mirror. QDL system was pumped by s XeCl excimer laser with 150 mJ pulse energy in a 20 ns pulse at 1 Hz repetition rate. Pulse-width of QDL was measured by a noncollinear intensity autocorrelator. The focused thckness was measured by changing the position of the focusing cylindrical lens. Pulse-width of QDL as a function of the focused thickness (273.0
) varied continuously from 86 ps to 201 ps.
The output characteristics of Ti:Sapphire laser pumped by dense plasma light
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 157~161
A Ti:Sapphire laser pumped by the HCP has been designed and fabricated to study the optimal pumping conditions for lasing. The fluorescence energy converter LD-490 has been used. The result showed that the threshold energy of Ti:Sapphire laser is 1.39 KJ and the best efficiency is
% at the concentration
Mol/l of LD-490 dye. However, the efficiencies were decreased with the decrease of dye concentrations. The maximum output energy was obtained at 50 Torr Ar pressure, when the input voltage was 15 kV. As a convert dye, BBQ, was added to LD-490 with the rate of 1:1, the output energy was increased, whereas the thereshold energy was decreased as 1.17 kJ.
Four-pass dye laser amplifier for the direct pulsed amplification of a tunable narrow-bandwidth continuous-wave laser
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 162~168
A new design of four-pass dye laser amplifier affording a narrow-bandwidth pulsed output is demonstrated to suppress the amplified spontaneous emission(ASE) carried by the amplifier output and reduce the possibility of parasitic oscillation in the amplifier. By the direct pulsed amplification of a cw 100 mW dye laser under a Q-switched doubled Nd:YAG laser pumping with energy of 5.6 mJ/pulse, high-peak-power pulsed output with 1.5-mJ energy in 130-MHz bandwidth is obtained corresponding to a power gain greater than
and an energy efficiency of 27%. The ASE ratio in the four-pass amplifier output is dramatically reduced by using a diffraction grating in the amplifier. Compared with the results obtained from the normal operation of the amplifier with no frequency-selective device, the ASE ratio is reduced by a factor in excess of 10 to remain under 1.5% of the amplifier output whereas the total output energy is slightly increased by ~4%.
Eye margin characteristics of 10Gb/s signals to the variation of optical signal to noise ratio and dispersion compensation
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 169~173
We have experimentally investigated the eye margin characteristics of intensity modulated 10Gb/s NRZ signals in optically amplified systems depending on optical signal-to-noise ratio and chromatic dispersion. For the practical system application, the minimum optical signal-to-noise ratio was 25 dB. We utilized the negative chirped transmitter and a dispersion compensation fiber to compensate the chromatic dispersion in single mode fiber. We found the optimum eye opening and receiver sensitivity in case of the residual dispersion of 0~+935 ps/nm.
Propagation loss measurement of silica slab waveguide using index matching fluid
Korean Journal of Optics and Photonics, volume 10, issue 2, 1999, Pages 174~177
The propagation loss of silica slab waveguides were measured by immersing slab waveguides into a index matching liqiud. Index matching liqiud was used for out-coupling the light from arbitrary points of slab waveguide. The measured value of propagation loss are 0.04 dB/cm and 0.09 dB at 1300 nm and 633 nm respectively.