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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Optical Society of Korea
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Journal DOI :
Optical Society of Korea
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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
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Regenerative Er-doped Fiber Amplifier System for High-repetition-rate Optical Pulses
Liu, Yan ; Wu, Kan ; Li, Nanxi ; Lan, Lanling ; Yoo, Seongwoo ; Wu, Xuan ; Shum, Perry Ping ; Zeng, Shuguang ; Tan, Xinyu ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 357~361
DOI : 10.3807/JOSK.2013.17.5.357
A regenerative Er-doped fiber amplifier system for a high-repetition-rate optical pulse train is investigated for the first time. A signal pulse train with a wavelength tuning range of 18 nm is produced by a passive mode-locked fiber laser based on a nonlinear polarization rotation technique. In order to realize the amplification, an optical delay-line is used to achieve time match between the pulses' interval and the period of pulse running through the regenerative amplifier. The 16 dB gain is obtained for an input pulse train with a launching power of -30.4 dBm, a center wavelength of 1563.4 nm and a repetition rate of 15.3 MHz. The output properties of signal pulses with different center wavelengths are also discussed. The pulse amplification is found to be different from the regenerative amplification system for CW signals.
Optical Implementation of Triple DES Algorithm Based on Dual XOR Logic Operations
Jeon, Seok Hee ; Gil, Sang Keun ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 362~370
DOI : 10.3807/JOSK.2013.17.5.362
In this paper, we propose a novel optical implementation of a 3DES algorithm based on dual XOR logic operations for a cryptographic system. In the schematic architecture, the optical 3DES system consists of dual XOR logic operations, where XOR logic operation is implemented by using a free-space interconnected optical logic gate method. The main point in the proposed 3DES method is to make a higher secure cryptosystem, which is acquired by encrypting an individual private key separately, and this encrypted private key is used to decrypt the plain text from the cipher text. Schematically, the proposed optical configuration of this cryptosystem can be used for the decryption process as well. The major advantage of this optical method is that vast 2-D data can be processed in parallel very quickly regardless of data size. The proposed scheme can be applied to watermark authentication and can also be applied to the OTP encryption if every different private key is created and used for encryption only once. When a security key has data of
pixels in size, our proposed method performs 2,048 DES blocks or 1,024 3DES blocks cipher in this paper. Besides, because the key length is equal to
attempts are required to find the correct key. Numerical simulations show the results to be carried out encryption and decryption successfully with the proposed 3DES algorithm.
Research on the Solar Concentrating Optical System for Solar Energy Utilization
Duan, Yimeng ; Yang, Huajun ; Jiang, Ping ; Wang, Ping ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 371~375
DOI : 10.3807/JOSK.2013.17.5.371
To improve the utilization efficiency of solar energy, a new solar optical concentrating system composed of a parabolic reflector with a square cross-section, a hyperbolic reflector with a square cross-section and two converging convex lenses has been designed. The proposed method can simultaneously focus and shape sun light into a square pattern on the solar panel. In addition, the total reflection property of photonic crystal within the range of the visible sunlight spectrum has been analyzed. Finally, the relationship between solar concentrating multiples and the diameter of the primary mirror has been discussed.
Simulation and Comparison of the Lighting Efficiency for Household Illumination with LEDs and Fluorescent Lamps
Sun, Wen-Shing ; Tien, Chuen-Lin ; Pan, Jui-Wen ; Yang, Tsung-Hsun ; Tsuei, Chih-Hsuan ; Huang, Yi-Han ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 376~383
DOI : 10.3807/JOSK.2013.17.5.376
The design of the LEDs lighting in general household illumination was proposed and compared with the fluorescent lighting in this study. Using the LED as a light source would promote energy saving lighting for household illumination purposes. We used the LightTools and DIALux software to design and simulate different standards of illuminance, different correlated color temperatures and different color rendering indices for household environments. The power consumption and efficiency of traditional illuminated light sources and an LED light source with the same standard of illuminance for lighting the household environment were analyzed and compared with each other. Finally, our results show the advantages of using white-light LEDs for lighting and household illumination.
Optical Image Split-encryption Based on Object Plane for Completely Removing the Silhouette Problem
Li, Weina ; Phan, Anh-Hoang ; Jeon, Seok-Hee ; Kim, Nam ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 384~391
DOI : 10.3807/JOSK.2013.17.5.384
We propose a split-encryption scheme on converting original images to multiple ciphertexts. This conversion introduces one random phase-only function (POF) to influence phase distribution of the preliminary ciphertexts. In the encryption process, the original image is mathematically split into two POFs. Then, they are modulated on a spatial light modulator one after another. And subsequently two final ciphertexts are generated by utilizing two-step phase-shifting interferometry. In the decryption process, a high-quality reconstructed image with relative error
can be achieved only when the summation of the two ciphertexts is Fresnel-transformed to the reconstructed plane. During the verification process, any silhouette information was invisible in the two reconstructed images from different single ciphertexts. Both of the two single REs are more than 0.6, which is better than in previous research. Moreover, this proposed scheme works well with gray images.
In-line Critical Dimension Measurement System Development of LCD Pattern Proposed by Newly Developed Edge Detection Algorithm
Park, Sung-Hoon ; Lee, Jeong-Ho ; Pahk, Heui-Jae ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 392~398
DOI : 10.3807/JOSK.2013.17.5.392
As the essential techniques for the CD (Critical Dimension) measurement of the LCD pattern, there are various modules such as an optics design, auto-focus [1-4], and precise edge detection. Since the operation of image enhancement to improve the CD measurement repeatability, a ring type of the reflected lighting optics is devised. It has a simpler structure than the transmission light optics, but it delivers the same output. The edge detection is the most essential function of the CD measurements. The CD measurement is a vital inspection for LCDs [5-6] and semiconductors [7-8] to improve the production yield rate, there are numbers of techniques to measure the CD. So in this study, a new subpixel algorithm is developed through facet modeling, which complements the previous sub-pixel edge detection algorithm. Currently this CD measurement system is being used in LCD manufacturing systems for repeatability of less than 30 nm.
Investigation of Strain Measurements using Digital Image Correlation with a Finite Element Method
Zhao, Jian ; Zhao, Dong ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 399~404
DOI : 10.3807/JOSK.2013.17.5.399
This article proposes a digital image correlation (DIC) strain measurement method based on a finite element (FE) algorithm. A two-step digital image correlation is presented. In the first step, the gradient-based subpixels technique is used to search the displacements of a region of interest of the specimen, and then the strain fields are obtained by utilizing the finite element method in the second step. Both simulation and experiment processing, including tensile strain deformation, show that the proposed method can achieve nearly the same accuracy as the cubic spline interpolation method in most cases and higher accuracy in some cases, such as the simulations of uniaxial tension with and without noise. The results show that it also has a good noise-robustness. Finally, this method is used in the uniaxial tensile testing for Dahurian Larch wood specimens with or without a hole, and the obtained strain values are close to the results which were obtained from the strain gauge and the cubic spline interpolation method.
Resolution Analysis of Axially Distributed Image Sensing Systems under Equally Constrained Resources
Cho, Myungjin ; Shin, Donghak ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 405~409
DOI : 10.3807/JOSK.2013.17.5.405
In this paper, a unifying framework to evaluate the depth resolution of axially distributed image sensing (ADS) systems under fixed resource constraints is proposed. The proposed framework enables one to evaluate the system performance as a function of system parameters such as the number of cameras, the number of pixels, pixel size, and so on. The Monte Carlo simulations are carried out to evaluate ADS system performance as a function of system parameters. To the best of our knowledge, this is the first report on quantitative analysis of ADS systems under fixed resource constraints.
3D Integral Imaging Display using Axially Recorded Multiple Images
Cho, Myungjin ; Shin, Donghak ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 410~414
DOI : 10.3807/JOSK.2013.17.5.410
In this paper, we propose a 3D display method combining a pickup process using axially recorded multiple images and an integral imaging display process. First, we extract the color and depth information of 3D objects for displaying 3D images from axially recorded multiple 2D images. Next, using the extracted depth map and color images, elemental images are computationally synthesized based on a ray mapping model between 3D space and an elemental image plane. Finally, we display 3D images optically by an integral imaging system with a lenslet array. To show the usefulness of the proposed system, we carry out optical experiments for 3D objects and present the experimental results.
Fringe-Order Determination Method in White-Light Phase-Shifting Interferometry for the Compensation of the Phase Delay and the Suppression of Excessive Phase Unwrapping
Kim, SeongRyong ; Kim, JungHwan ; Pahk, HeuiJae ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 415~422
DOI : 10.3807/JOSK.2013.17.5.415
White-light phase-shifting interferometry (WLPSI) is widely recognized as a standard method to measure shapes with high resolution over a long distance. In practical applications, WLPSI, however, is associated with some degree of ambiguity of its phase, which occurs due to a phase delay, which is the offset between the phase of the fringes and the fringe envelope peak position. In this paper, a new algorithm is proposed for the determination of a fringe order suitable for samples in which the phase delay mainly occurs due to noise, diffraction and a steep angle. The concepts of the decouple factor and the connectivity are introduced and a method for calculating the decouple factor and the connectivity is developed. With the phase-unwrapping procedure which considers these values, it is demonstrated that our algorithm determines the correct fringe order. To verify the performance of the algorithm, a simulation was performed with the virtual step height under noise. Some specimens such as step height standard and a column spacer with a steep angle are also measured with a Mirau interference microscope, after which the algorithm is shown to be effective and robust.
Nano-porous Silicon Microcavity Sensors for Determination of Organic Fuel Mixtures
Pham, Van Hoi ; Bui, Huy ; Hoang, Le Ha ; Nguyen, Thuy Van ; Nguyen, The Anh ; Pham, Thanh Son ; Ngo, Quang Minh ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 423~427
DOI : 10.3807/JOSK.2013.17.5.423
We present the preparation and characteristics of liquid-phase sensors based on nano-porous silicon multilayer structures for determination of organic content in gasoline. The principle of the sensor is a determination of the cavity-resonant wavelength shift caused by refractive index change of the nano-porous silicon multilayer cavity due to the interaction with liquids. We use the transfer matrix method (TMM) for the design and prediction of characteristics of microcavity sensors based on nano-porous silicon multilayer structures. The preparation process of the nano-porous silicon microcavity is based on electrochemical etching of single-crystal silicon substrates, which can exactly control the porosity and thickness of the porous silicon layers. The basic characteristics of sensors obtained by experimental measurements of the different liquids with known refractive indices are in good agreement with simulation calculations. The reversibility of liquid-phase sensors is confirmed by fast complete evaporation of organic solvents using a low vacuum pump. The nano-porous silicon microcavity sensors can be used to determine different kinds of organic fuel mixtures such as bio-fuel (E5), A92 added ethanol and methanol of different concentrations up to 15%.
Flexible Reflective Color Displays using Thermochromic Pigments
Heo, Kyong Chan ; Sohn, Youngku ; Yi, Jonghoon ; Kwon, Jin Hyuk ; Gwag, Jin Seog ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 428~432
DOI : 10.3807/JOSK.2013.17.5.428
This research presents a flexible reflective thermochromic display (TCD) comprised of thermochromic pigments and a patterned indium tin oxide (ITO) film coated on a polyethylene naphthalate (PEN) substrate, and the display's thermo-optical characteristics. The display showed maximum red, green, and blue reflectances of 30%, 38%, and 29%, respectively. Furthermore, the display exhibited a continuous grey color when the temperature was changed continuously. As a flexible display, the display showed reliable thermo-optical performance without image damage even when highly bent. We expect the proposed TCD will be used in outdoor information display applications where low cost is a key factor.
Evaluation of Chromatic-Dispersion-Dependent Four-Wave-Mixing Efficiency in Hydrogenated Amorphous Silicon Waveguides
Kim, Dong Wook ; Jeong, Heung Sun ; Jeon, Sang Chul ; Park, Sang Hyun ; Yoo, Dong Eun ; Kim, Ki Nam ; An, Shin Mo ; Lee, El-Hang ; Kim, Kyong Hon ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 433~440
DOI : 10.3807/JOSK.2013.17.5.433
We present an experimental and numerical study of spectral profiles of effective group indices of hydrogenated amorphous silicon (a-Si:H) waveguides and of their chromatic-dispersion effect on the four-wave-mixing (FWM) signal generation. The a-Si:H waveguides of 220-nm thickness and three different widths of 400, 450 and 500 nm were fabricated by using the conventional CMOS device processes on a
bottom layer deposited on 8-inch Si wafers. Mach-Zehnder interferometers (MZIs) were formed with the a-Si:H waveguides, and used for precise measurement of the effective group indices and thus for determination of the spectral profile of the waveguides' chromatic dispersion. The wavelength ranges for the FWM-signal generation were about 45, 75 and 55 nm for the 400-, 450- and 500-nm-wide waveguides, respectively, at the pump wavelength of 1532 nm. A widest wavelength range for the efficient FWM process was observed with the 450-nm-wide waveguide having a zero-dispersion near the pump wavelength.
Time-Domain Numerical Investigation of Ring Resonator Optical Delay Devices
Chung, Youngchul ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 441~446
DOI : 10.3807/JOSK.2013.17.5.441
A split-step time-domain model for the analysis of pulse delay characteristics through ring resonator all-pass filters (APF's) is developed and its accuracy is checked. The dependence of the delay time and pulse distortion on the coupling ratios is investigated using the model. It is observed that the bandwidth of the APF's needs to be wide enough to minimize the pulse distortion.
Optical Design and Optimization of a Micro Zoom System with Liquid Lenses
Zhang, Wei ; Li, Dan ; Guo, Xin ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 447~453
DOI : 10.3807/JOSK.2013.17.5.447
A micro zoom system without moving elements by use of two liquid lenses is designed and optimized in this paper. The zoom equations of the system composed of two liquid lenses are deduced. The structure parameters including radius and thickness of a conical double-liquid electrowetting based lens are analyzed and calculated. Because the liquid thickness varies non-linearly with the radius of the interface, it's very difficult to optimize a real liquid lens using commercial optical design software directly. Through the Application Programming Interface (API) of the optical design software CODE V, a zoom system with two real electrowetting based liquid lenses is modeled and optimized. A two-liquid-lens zoom system without moving elements, with a zoom factor of 1.8 and a compact structure of 10 mm is designed for illustration. This can be useful for the camera design of mobile phones, tablets and so on. And this paper presents a convenient way of designing and optimizing a zoom system including liquid lenses by commercial optical design software.
Compound Explosives Detection and Component Analysis via Terahertz Time-Domain Spectroscopy
Choi, Jindoo ; Ryu, Sung Yoon ; Kwon, Won Sik ; Kim, Kyung-Soo ; Kim, Soohyun ;
Journal of the Optical Society of Korea, volume 17, issue 5, 2013, Pages 454~460
DOI : 10.3807/JOSK.2013.17.5.454
We present qualitative and quantitative component analyses on compound explosives via Terahertz time-domain spectroscopy (THz-TDS) based on a combination of wavelet thresholding and wavelength selection. Despite its importance, the field of signal processing of THz signals of compound plastic explosives is relatively unexplored. In this paper, experiment results from explosives Composition B-3 and Pentolite are newly presented, suggesting a novel signal processing procedure for in situ compound explosives detection. The proposed signal processing method demonstrates effective component analysis even in noisy and humid environments, showing significant decrease in component concentration percentage error of approximately 22.7% for Composition B-3 and 48.8% for Pentolite.