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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Optical Society of Korea
Journal Basic Information
Journal DOI :
Optical Society of Korea
Editor in Chief :
Shin, Jung Hoon
Volume & Issues
Volume 17, Issue 6 - Dec 2013
Volume 17, Issue 5 - Oct 2013
Volume 17, Issue 4 - Aug 2013
Volume 17, Issue 3 - Jun 2013
Volume 17, Issue 2 - Apr 2013
Volume 17, Issue 1 - Feb 2013
Selecting the target year
Development of an Optical Tissue Clearing Laser Probe System
Yeo, Changmin ; Kang, Heesung ; Bae, Yunjin ; Park, Jihoon ; Nelson, J. Stuart ; Lee, Kyoung-Joung ; Jung, Byungjo ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 289~295
DOI : 10.3807/JOSK.2013.17.4.289
Although low-level laser therapy (LLLT) has been a valuable therapeutic technology in the clinic, its efficacy may be reduced in deep tissue layers due to strong light scattering which limits the photon density. In order to enhance the photon density in deep tissue layers, this study developed an optical tissue clearing (OTC) laser probe (OTCLP) system which can utilize four different OTC methods: 1) tissue temperature control from 40 to
; 2) laser pulse frequency from 5 to 30 Hz; 3) glycerol injection at a local region; and 4) a combination of the aforementioned three methods. The efficacy of the OTC methods was evaluated and compared by investigating laser beam profiles in ex-vivo porcine skin samples. Results demonstrated that total (peak) intensity at full width at half maximum of laser beam profile when compared to control data was increased: 1) 1.21(1.39)-fold at
; 2) 1.22 (1.49)-fold at a laser pulse frequency of 5 Hz; 3) 1.64 (2.41)-fold with 95% glycerol injection; 4) 1.86 (3.4)-fold with the combination method. In conclusion, the OTCLP system successfully improved the laser photon density in deep tissue layers and may be utilized as a useful tool in LLLT by increasing laser photon density.
LDL Cholesterol Testing Device using Serial Reflected Face-to-Face Mirror System
Choi, Min-Seong ; Yoo, Jae-Chern ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 296~299
DOI : 10.3807/JOSK.2013.17.4.296
A low density lipoprotein (LDL) cholesterol testing device, structured with serial reflected face-to-face mirror (SRM) allowing spectrophotometry measurements, is presented. The spectrophotometry has been employed to measure the amount of light that a sample absorbs, but it generally should have had path length longer than 10 mm to secure enough sensitivity. Such requirement of path length has often been problematic in implementing a thin type of lab on a disc (LOD). We developed the SRM system which was implemented in a detection chamber with 1.4mm thickness, providing path length longer than 10mm, and thus straightforwardly being applicable to LOD as thin as a compact disc. The experimental results show that the SRM system gives not only a much thinner design compared to the conventional spectrophotometry-based LOD but also a comparable performance to already commercialized spectrometers.
Discernibly Temperature-insensitive Pressure Sensitivity in Porous Random-Hole Optical Fibers
Kim, Jeong ; Kominsky, Dan ; Pickrell, Gary ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 300~304
DOI : 10.3807/JOSK.2013.17.4.300
Novel breakthrough random-hole optical fibers (RHOFs) are fabricated in a draw tower facility, by tapering an optical fiber preform packed with a silica powder mixture capable of producing air holes in situ at the high temperature of tens of hundreds in degrees Celsius. Structural and propagation characteristics of the porous RHOF are explained briefly. Experimental investigations of the invented RHOF are performed for pressure sensor applications. Remarkable results are obtained for the RHOF with desirable pressure sensitivity independent of temperature, as is required for harsh conditions as in oil reservoirs.
Time-dependent Analysis of Optical Receivers Using Receiver Eigenmodes
Seo, Kyung Hee ; Lee, Jae Seung ; Willner, Alan E. ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 305~311
DOI : 10.3807/JOSK.2013.17.4.305
Using receiver eigenmodes, we perform a time-dependent analysis of optical receivers whose optical inputs are corrupted by the amplified spontaneous emission. We use Gaussian receivers for the analysis with Gaussian input pulses. We find the number of contributing eigenmodes increases as the measurement time moves from the pulse center towards the pulse edges at the output of the optical receiver`s electrical filter. This behavior is dependent on the bandwidth ratio between the optical and the electrical filters as well as the input pulse`s time width.
A Fiber Laser Spectrometer Demodulation of Fiber Bragg Grating Sensors for Measurement Linearity Enhancement
Kim, Hyunjin ; Song, Minho ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 312~316
DOI : 10.3807/JOSK.2013.17.4.312
A novel fiber-optic sensor system is suggested in which fiber Bragg grating sensors are demodulated by a wavelength-sweeping fiber laser source and a spectrometer. The spectrometer consists of a diffraction grating and a 512-pixel photo-diode array. The reflected Bragg wavelength information is transformed into spatial intensity distribution on the photo-diode array. The peak locations linearly correspond to the Bragg wavelengths, regardless of the nonlinearities in the wavelength tuning mechanism of the fiber laser. The high power density of the fiber laser enables obtaining high signal-to-noise ratio outputs. The improved demodulation characteristics were experimentally demonstrated with a fiber Bragg grating sensor array with 5 gratings. The sensor outputs were in much more linear fashion compared with the conventional tunable band-pass filter demodulation. Also it showed advantages in signal processing, due to the high level of photo-diode array signals, over the broadband light source system, especially in measurement of fast varying dynamic physical quantities.
3D Measurement of TSVs Using Low Numerical Aperture White-Light Scanning Interferometry
Jo, Taeyong ; Kim, Seongryong ; Pahk, Heuijae ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 317~322
DOI : 10.3807/JOSK.2013.17.4.317
We have proposed and demonstrated a low numerical aperture technique to measure the depth of through silicon vias (TSVs) using white-light scanning interferometry. The high aspect ratio hole like TSV`s was considered to be impossible to measure using conventional optical methods due to low visibility at the bottom of the hole. We assumed that the limitation of the measurement was caused by reflection attenuation in TSVs. A novel interference theory which takes the structural reflection attenuation into consideration was proposed and simulated. As a result, we figured out that the low visibility in the interference signal was caused by the unbalanced light intensity between the object and the reference mirror. Unbalanced light can be balanced using an aperture at the illumination optics. As a result of simulation and experiment, we figured out that the interference signal can be enhanced using the proposed technique. With the proposed optics, the depth of TSVs having an aspect ratio of 11.2 was measured in 5 seconds. The proposed method is expected to be an alternative method for 3-D inspection of TSVs.
Preliminary Study of the Measurement of Foreign Material in Galvanic Corrosion Using Laser Ultrasonic
Hong, Kyung Min ; Kang, Young June ; Park, Nak Kyu ; Choi, In Young ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 323~327
DOI : 10.3807/JOSK.2013.17.4.323
A laser ultrasonic inspection system has the advantage of nondestructive testing. It is a non-contact mode using a laser interferometer to measure the vertical displacement of the surface of a material caused by the propagation of ultrasonic signals with the remote ultrasonic generated by laser. After raising the ultrasonic signal with a broadband frequency range using a pulsed laser beam, the laser beam is focused to a small point to measure the ultrasonic signal because it provides an excellent measurement resolution. In this paper, foreign materials are measured by a non-destructive and non-contact method using the laser ultrasonic inspection system. Mixed foreign material on the corroded part is assumed and the laser ultrasonic experiment is conducted. An ultrasonic wave is generated by pulse laser from the back of the specimen and an ultrasonic signal is acquired from the same location of the front side using continuous wave laser and Confocal Fabry-Perot Interferometer (CFPI). The characteristic of the ultrasonic signal of existing foreign material is analyzed and the location and size of foreign material is measured.
A New Application of Human Visual Simulated Images in Optometry Services
Chang, Lin-Song ; Wu, Bo-Wen ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 328~335
DOI : 10.3807/JOSK.2013.17.4.328
Due to the rapid advancement of auto-refractor technology, most optometry shops provide refraction services. Despite their speed and convenience, the measurement values provided by auto-refractors include a significant degree of error due to psychological and physical factors. Therefore, there is a need for repetitive testing to obtain a smaller mean error value. However, even repetitive testing itself might not be sufficient to ensure accurate measurements. Therefore, research on a method of measurement that can complement auto-refractor measurements and provide confirmation of refraction results needs to be conducted. The customized optometry model described herein can satisfy the above requirements. With existing technologies, using human eye measurement devices to obtain relevant individual optical feature parameters is no longer difficult, and these parameters allow us to construct an optometry model for individual eyeballs. They also allow us to compute visual images produced from the optometry model using the CODE V macro programming language before recognizing the diffraction effects visual images with the neural network algorithm to obtain the accurate refractive diopter. This study attempts to combine the optometry model with the back-propagation neural network and achieve a double check recognition effect by complementing the auto-refractor. Results show that the accuracy achieved was above 98% and that this application could significantly enhance the service quality of refraction.
Design of Off-axis Wide Angle Lens for the Automobile Application
Kim, Tae Young ; Shin, Min-Ho ; Kim, Young-Joo ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 336~343
DOI : 10.3807/JOSK.2013.17.4.336
Recently various types of driver assistance systems have been used for automobiles. In 2008, the U.S Congress passed a law which required that most cars be equipped with devices to warn objects behind the vehicle. Because of that, market of rear view cameras is expected to rise dramatically. Therefore many suppliers try to provide a wide angle camera for car makers. But a high distortion is caused by the wide angle might result in lower image quality. In order to improve the image quality, normally we use an algorithm to correct a distortion. Though we can improve the distorted image by correction algorithm, we must pay more cost to use it. In this paper, we propose a new optical system reducing a distortion in contrast to a conventional lens without cost. In other words, we can see only an area of interest. That is similar to reducing a field of view. Using a new optical system, we can get a less distorted image. In order to view an area of interest, we introduce an off axis optical system having refractive surfaces and reflective surfaces. In this paper, we describe the results of design and, evaluation of an off axis wide angle compact imaging system. In comparison to conventional wide angle lens, we can get the improvement of MTF, distortion, and lateral color aberrations. And we also can reduce a total cost because we don`t need the outer apparatus or bracket to mount on the car.
Computer Simulation for Gradual Yellowing of Aged Lens and Its Application for Test Devices
Kim, Bog G. ; Han, Jeong-Won ; Park, Soo-Been ;
Journal of the Optical Society of Korea, volume 17, issue 4, 2013, Pages 344~349
DOI : 10.3807/JOSK.2013.17.4.344
This paper proposes a simulation algorithm to assess the gradual yellowing vision of the elderly, which refers to the predominance of yellowness in their vision due to aging of the ocular optic media. This algorithm employed the spectral transmittance property of a yellow filter to represent the color appearance perceived by elderly people with yellow vision, and modeled the changes in the color space through a spectrum change in light using the yellow filter effect. The spectral reflectivity data of 1269 Munsell matte color chips were used as reference data. Under the standard conditions of a D65 illuminant and a
observer of 1964 CIE, the spectrum of the 1269 Munsell colors were processed through the yellow filter effect to simulate yellow vision. Various degrees of yellow vision were modeled according to the transmittance percentage of the yellow filter. The color differences before and after the yellow filter effect were calculated using the DE2000 formula, and the color pairs were selected based on the color difference function. These color pairs are distinguishable through normal vision, but the color difference diminishes as the degree of yellow vision increases. Assuming 80% of yellow vision effect, 17 color pairs out of
pairs were selected, and for the 90% of yellow vision effect, only 3 color pairs were selected. The result of this study can be utilized for the diagnosis system of gradual yellow vision, making various types of test charts with selected color pairs.