Pub Date : 2016-12-25DOI: 10.3807/JOSK.2016.20.6.653
M. Ahmadi, K. Forooraghi, R. Faraji-Dana, M. Ghaffari‐Miab
An optimized multilayer superlens is designed, using a rigorous and efficient approach based on the method of moments (MoM) in conjunction with a simulated annealing (SA) algorithm. For the MoM solution, fast evaluation of closed-form Green’s functions (GFs) in the spatial domain is performed by applying the complex-image (CI) technique, which obviates the time-consuming numerical evaluation of Sommerfeld integrals. The imaging capability of the superlens is examined with the correlation coefficient; results show that using circular polarization for the incident wave can improve this coefficient. To validate the proposed method, finite-element-based simulations are exploited, which reveal the method’s accuracy and computational efficiency. Simulation results indicate that the designed structure is capable of producing two-dimensional sub-diffraction-limited images in the visible range, which may make it more versatile for practical applications. Finally, as a considerable finding, it is demonstrated for the proposed design that using circularly polarized illumination provides improved super-resolving performance, compared to linearly polarized illumination.
{"title":"Two-Dimensional Sub-diffraction-limited Imaging by an Optimized Multilayer Superlens","authors":"M. Ahmadi, K. Forooraghi, R. Faraji-Dana, M. Ghaffari‐Miab","doi":"10.3807/JOSK.2016.20.6.653","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.6.653","url":null,"abstract":"An optimized multilayer superlens is designed, using a rigorous and efficient approach based on the method of moments (MoM) in conjunction with a simulated annealing (SA) algorithm. For the MoM solution, fast evaluation of closed-form Green’s functions (GFs) in the spatial domain is performed by applying the complex-image (CI) technique, which obviates the time-consuming numerical evaluation of Sommerfeld integrals. The imaging capability of the superlens is examined with the correlation coefficient; results show that using circular polarization for the incident wave can improve this coefficient. To validate the proposed method, finite-element-based simulations are exploited, which reveal the method’s accuracy and computational efficiency. Simulation results indicate that the designed structure is capable of producing two-dimensional sub-diffraction-limited images in the visible range, which may make it more versatile for practical applications. Finally, as a considerable finding, it is demonstrated for the proposed design that using circularly polarized illumination provides improved super-resolving performance, compared to linearly polarized illumination.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"653-662"},"PeriodicalIF":0.0,"publicationDate":"2016-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70141416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-25DOI: 10.3807/JOSK.2016.20.5.541
D. Yuan, Li Shutao, Guan Jia-Yin, Zhang Xi-he, J. Guangyong
In this paper, by using the Rayleigh-Sommer field theory and the cross-spectral density function, the analytical expression for the intensity distribution of a double half-Gaussian hollow beam in a turbulent atmosphere is obtained. The influence of the initial spot size of this beam on its propagation properties in a turbulent atmosphere is simulated, and the intensity distributions for such beams with different spot sizes are obtained. The results show that the initial spot size has an important influence on the propagation properties in the near field, while this influence in the far field is very weak.
{"title":"The Influence of the Initial Spot Size of a Double Half-Gaussian Hollow Beam on Its Propagation Characteristics in a the Turbulent Atmosphere","authors":"D. Yuan, Li Shutao, Guan Jia-Yin, Zhang Xi-he, J. Guangyong","doi":"10.3807/JOSK.2016.20.5.541","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.541","url":null,"abstract":"In this paper, by using the Rayleigh-Sommer field theory and the cross-spectral density function, the analytical expression for the intensity distribution of a double half-Gaussian hollow beam in a turbulent atmosphere is obtained. The influence of the initial spot size of this beam on its propagation properties in a turbulent atmosphere is simulated, and the intensity distributions for such beams with different spot sizes are obtained. The results show that the initial spot size has an important influence on the propagation properties in the near field, while this influence in the far field is very weak.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"541-546"},"PeriodicalIF":0.0,"publicationDate":"2016-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-25DOI: 10.3807/JOSK.2016.20.5.547
Jae-Yu Bae, Sang-Woo Kim, T. Park, Hyun-Ja Cho, YoungDuk An, Sanghyun A Kim, HyunWoon Ra, Young-Moo Cho, JaeSeok Koh, Mee-Suk Jung
A fishing lamp is the instrument for attracting distributed fish to a certain place, and is the lighting system mainly used in fishery. In the inshore fishing, most fishing lamps are used for squid and hairtail jigging fishing, and the light source of the fishing lamps mainly used is metal halide with 1.5 KW in electric power consumption. We will analyze the irradiance distribution according to depth because squid is attracted towards light. To analyze irradiance distribution by such fishing lamps, data for seawater Type-II among the seawater types defined in 1976 are applied to East Sea. However, the Type-II data have limitations in analyzing precise seawater transmission characteristics, due to insufficient information on deep seawater. This paper analyzed the irradiance distribution of fishing lamps using the measurement of transmission characteristics in the seawater in East Sea up to 100 m underwater instead of Type-II data, which is not sufficient for transmission. A compensation factor was drawn between the actual measurement data and Type-II data through seawater transmission characteristics simulation.
{"title":"Irradiance Distribution in East Sea by Using Measured Optical Properties for Squid Jigging Vessels","authors":"Jae-Yu Bae, Sang-Woo Kim, T. Park, Hyun-Ja Cho, YoungDuk An, Sanghyun A Kim, HyunWoon Ra, Young-Moo Cho, JaeSeok Koh, Mee-Suk Jung","doi":"10.3807/JOSK.2016.20.5.547","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.547","url":null,"abstract":"A fishing lamp is the instrument for attracting distributed fish to a certain place, and is the lighting system mainly used in fishery. In the inshore fishing, most fishing lamps are used for squid and hairtail jigging fishing, and the light source of the fishing lamps mainly used is metal halide with 1.5 KW in electric power consumption. We will analyze the irradiance distribution according to depth because squid is attracted towards light. To analyze irradiance distribution by such fishing lamps, data for seawater Type-II among the seawater types defined in 1976 are applied to East Sea. However, the Type-II data have limitations in analyzing precise seawater transmission characteristics, due to insufficient information on deep seawater. This paper analyzed the irradiance distribution of fishing lamps using the measurement of transmission characteristics in the seawater in East Sea up to 100 m underwater instead of Type-II data, which is not sufficient for transmission. A compensation factor was drawn between the actual measurement data and Type-II data through seawater transmission characteristics simulation.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"547-556"},"PeriodicalIF":0.0,"publicationDate":"2016-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-25DOI: 10.3807/JOSK.2016.20.5.623
Kang-Yeob Park, Eun-Jung Yoon, W. Oh
A power-adjustable fully-integrated CMOS optical receiver with multi-rate clock-and-data recovery circuit is presented in standard 65-nm CMOS technology. With supply voltage scaling, key features of the optical receiver such as bandwidth, power efficiency, and optical sensitivity can be automatically optimized according to the bit rates. The prototype receiver has -23.7 dBm to -15.4 dBm of optical sensitivity for 10 -9 bit error rate with constant conversion gain around all target bit rates from 1.62Gbps to 8.1 Gbps. Power efficiency is less than 9.3 pJ/bit over all operating ranges.
{"title":"A Power-adjustable Fully-integrated CMOS Optical Receiver for Multi-rate Applications","authors":"Kang-Yeob Park, Eun-Jung Yoon, W. Oh","doi":"10.3807/JOSK.2016.20.5.623","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.623","url":null,"abstract":"A power-adjustable fully-integrated CMOS optical receiver with multi-rate clock-and-data recovery circuit is presented in standard 65-nm CMOS technology. With supply voltage scaling, key features of the optical receiver such as bandwidth, power efficiency, and optical sensitivity can be automatically optimized according to the bit rates. The prototype receiver has -23.7 dBm to -15.4 dBm of optical sensitivity for 10 -9 bit error rate with constant conversion gain around all target bit rates from 1.62Gbps to 8.1 Gbps. Power efficiency is less than 9.3 pJ/bit over all operating ranges.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"623-627"},"PeriodicalIF":0.0,"publicationDate":"2016-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-25DOI: 10.3807/JOSK.2016.20.5.628
SaeJune Park, S. Yoon, Y. Ahn
We studied experimentally and theoretically the vertical range of the confined electric field in the gap area of metamaterials, which was analyzed for various gap widths using terahertz time-domain spectroscopy. We measured the resonant frequency as a function of the thickness of poly(methyl methacrylate) in the range 0 to 3.2 μm to quantify the effective detection volumes. We found that the effective vertical range of the metamaterial is determined by the size of the gap width. The vertical range was found to decrease as the gap width of the metamaterial decreases, whereas the sensitivity is enhanced as the gap width decreases due to the highly concentrated electric field. Our experimental findings are in good agreement with the finite-difference time-domain simulation results. Finally, a numerical expression was obtained for the vertical range as a function of the gap width. This expression is expected to be very useful for optimizing the sensing efficiency.
{"title":"Effective Sensing Volume of Terahertz Metamaterial with Various Gap Widths","authors":"SaeJune Park, S. Yoon, Y. Ahn","doi":"10.3807/JOSK.2016.20.5.628","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.628","url":null,"abstract":"We studied experimentally and theoretically the vertical range of the confined electric field in the gap area of metamaterials, which was analyzed for various gap widths using terahertz time-domain spectroscopy. We measured the resonant frequency as a function of the thickness of poly(methyl methacrylate) in the range 0 to 3.2 μm to quantify the effective detection volumes. We found that the effective vertical range of the metamaterial is determined by the size of the gap width. The vertical range was found to decrease as the gap width of the metamaterial decreases, whereas the sensitivity is enhanced as the gap width decreases due to the highly concentrated electric field. Our experimental findings are in good agreement with the finite-difference time-domain simulation results. Finally, a numerical expression was obtained for the vertical range as a function of the gap width. This expression is expected to be very useful for optimizing the sensing efficiency.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"628-632"},"PeriodicalIF":0.0,"publicationDate":"2016-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70141327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-25DOI: 10.3807/JOSK.2016.20.5.579
S. Yeom
Integral imaging combined with photon-counting detection has been researched for three-dimensional information sensing under low-light-level conditions. This paper addresses the extraction of distance information with photon-counting integral imaging. The longitudinal distance to the object is obtained utilizing photon-counting elemental images. The pixel disparity is estimated by maximizing the nonlinear correlation of photocounts. The first- and second-order statistical properties of the nonlinear correlation are theoretically derived. In the experiments, these properties are verified by varying the mean number of photocounts in the scene. The average distance is compared to that from the intensity information, showing the robustness of the proposed system even at low photocounts.
{"title":"Extraction of Distance Information with Nonlinear Correlation of Photon-Counting Integral Imaging","authors":"S. Yeom","doi":"10.3807/JOSK.2016.20.5.579","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.579","url":null,"abstract":"Integral imaging combined with photon-counting detection has been researched for three-dimensional information sensing under low-light-level conditions. This paper addresses the extraction of distance information with photon-counting integral imaging. The longitudinal distance to the object is obtained utilizing photon-counting elemental images. The pixel disparity is estimated by maximizing the nonlinear correlation of photocounts. The first- and second-order statistical properties of the nonlinear correlation are theoretically derived. In the experiments, these properties are verified by varying the mean number of photocounts in the scene. The average distance is compared to that from the intensity information, showing the robustness of the proposed system even at low photocounts.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"579-585"},"PeriodicalIF":0.0,"publicationDate":"2016-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-25DOI: 10.3807/JOSK.2016.20.5.575
D. Gunawardena, M. Lai, K. Lim, H. Ahmad
The thermal endurance of fiber Bragg gratings (FBGs), written with the aid of 193-nm ArF excimer laser irradiation on H2-loaded Ge/B codoped silica fiber, and pretreated with a CO2 laser and a subsequent slow cooling process, is investigated. These treated gratings show relatively less degradation of grating strength during the thermal annealing procedure. The thermal decay characteristics of treated and untreated fiber, recorded over a time period of 9 hours, have been compared. The effect on the Bragg transmission depth (BTD) and the center-wavelength shift, as well as the growth of refractive-index change during the grating inscription process for both treated and untreated fiber, are analyzed.
{"title":"Impact of CO2Laser Pretreatment on the Thermal Endurance of Bragg Gratings","authors":"D. Gunawardena, M. Lai, K. Lim, H. Ahmad","doi":"10.3807/JOSK.2016.20.5.575","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.575","url":null,"abstract":"The thermal endurance of fiber Bragg gratings (FBGs), written with the aid of 193-nm ArF excimer laser irradiation on H2-loaded Ge/B codoped silica fiber, and pretreated with a CO2 laser and a subsequent slow cooling process, is investigated. These treated gratings show relatively less degradation of grating strength during the thermal annealing procedure. The thermal decay characteristics of treated and untreated fiber, recorded over a time period of 9 hours, have been compared. The effect on the Bragg transmission depth (BTD) and the center-wavelength shift, as well as the growth of refractive-index change during the grating inscription process for both treated and untreated fiber, are analyzed.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"575-578"},"PeriodicalIF":0.0,"publicationDate":"2016-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.3807/JOSK.2016.20.5.607
Yeh-Chan Ahn, C. Oak, Jung-Eun Park, M. Jung, Jae-Hun Kim, Hae-Young Lee, Sung Won Kim, Eun‐Kee Park, M. Jung
The pleura is known as an end target organ of exposure to toxic environmental materials such as fine particulate matter and asbestos. Moreover, long-term exposure to hazardous materials can eventually lead to fatal lung disease such as diffuse pleural fibrosis or mesothelioma. Chest computed tomography (CT) and ultrasound are gold standard imaging modalities for detection of advanced pleural disease. However, a diagnostic tool for early detection of pleural reaction has not been developed yet due to difficulties in imaging ultra-fine structure of the pleura. Optical coherence tomography (OCT), which provides cross-sectional images of micro tissue structures at a resolution of 2-10 µm, can image the mesothelium with a thickness of ~100 µm and therefore enables investigation of the early pleural reaction. In this study, we induced the early pleural reaction according to a time sequence after pleurodesis using talc, which has been widely used in the clinical field. The pleural reaction in talc grouped according to the time sequence (1st, 2nd, 4th weeks) showed a significant thickening (average thickness: 45 ± 7.5 µm, 80 ± 10.7 µm, 90 ± 12.5 µm), while the pleural reaction in sham and normal groups showed pleural change from normal to minimal thickening (average thickness: 16 ± 5.5 µm, 17 ± 4.5 µm, 15 ± 6.5 µm, and 12 ± 7.5 µm, 13 ± 2.5 µm, 12 ± 3.5 µm). The measurement of pleural reaction by pathologic examinations was well-matched with the measurement by OCT images. This is the first study for measuring the thickness of pleural reactions using a biophotonic modality such as OCT. Our results showed that OCT can be useful for evaluating the early pleural reaction.
{"title":"Ex vivo High-resolution Optical Coherence Tomography (OCT) Imaging of Pleural Reaction after Pleurodesis Using Talc","authors":"Yeh-Chan Ahn, C. Oak, Jung-Eun Park, M. Jung, Jae-Hun Kim, Hae-Young Lee, Sung Won Kim, Eun‐Kee Park, M. Jung","doi":"10.3807/JOSK.2016.20.5.607","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.607","url":null,"abstract":"The pleura is known as an end target organ of exposure to toxic\u0000environmental materials such as fine particulate matter and asbestos.\u0000Moreover, long-term exposure to hazardous materials can eventually lead to\u0000fatal lung disease such as diffuse pleural fibrosis or mesothelioma. Chest\u0000computed tomography (CT) and ultrasound are gold standard imaging\u0000modalities for detection of advanced pleural disease. However, a\u0000diagnostic tool for early detection of pleural reaction has not been\u0000developed yet due to difficulties in imaging ultra-fine structure of the\u0000pleura. Optical coherence tomography (OCT), which provides cross-sectional\u0000images of micro tissue structures at a resolution of 2-10 µm, can\u0000image the mesothelium with a thickness of ~100 µm and therefore\u0000enables investigation of the early pleural reaction. In this study, we\u0000induced the early pleural reaction according to a time sequence after\u0000pleurodesis using talc, which has been widely used in the clinical field.\u0000The pleural reaction in talc grouped according to the time sequence (1st,\u00002nd, 4th weeks) showed a significant thickening (average thickness: 45\u0000± 7.5 µm, 80 ± 10.7 µm, 90 ± 12.5 µm), while\u0000the pleural reaction in sham and normal groups showed pleural change from\u0000normal to minimal thickening (average thickness: 16 ± 5.5 µm, 17\u0000± 4.5 µm, 15 ± 6.5 µm, and 12 ± 7.5 µm, 13\u0000± 2.5 µm, 12 ± 3.5 µm). The measurement of pleural\u0000reaction by pathologic examinations was well-matched with the measurement\u0000by OCT images. This is the first study for measuring the thickness of\u0000pleural reactions using a biophotonic modality such as OCT. Our results\u0000showed that OCT can be useful for evaluating the early pleural\u0000reaction.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"607-613"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.3807/JOSK.2016.20.5.563
D. Park, H. Chu, J. Kyoung, S. Choi
We report a theoretical research for the condition of electromagnetic shield breaching when a narrow aperture is punctured in thin metal film. To calculate electromagnetic field transmission through a narrow slit, a Rayleigh wave expansion has been applied for free standing, thin metal film. We found that the DC electric field allows perfect transmission when the length of the slit is infinite, regardless of the other geometrical factors such as slitwidth and thickness. Slitwidth dependent transmission spectra as a function of frequency shows a cutoff frequency that decreases almost linearly to the slitwidth, giving that almost successful shielding is only possible when the slitwidth is smaller than 1 micron.
{"title":"A Breaching of Electromagnetic Shielding by Narrow Aperture in Metal Film","authors":"D. Park, H. Chu, J. Kyoung, S. Choi","doi":"10.3807/JOSK.2016.20.5.563","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.563","url":null,"abstract":"We report a theoretical research for the condition of\u0000 electromagnetic shield breaching when a narrow aperture is punctured in\u0000 thin metal film. To calculate electromagnetic field transmission through a\u0000 narrow slit, a Rayleigh wave expansion has been applied for free standing,\u0000 thin metal film. We found that the DC electric field allows perfect\u0000 transmission when the length of the slit is infinite, regardless of the\u0000 other geometrical factors such as slitwidth and thickness. Slitwidth\u0000 dependent transmission spectra as a function of frequency shows a cutoff\u0000 frequency that decreases almost linearly to the slitwidth, giving that\u0000 almost successful shielding is only possible when the slitwidth is smaller\u0000 than 1 micron.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"563-566"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.3807/JOSK.2016.20.5.601
Changmin Lee, J. Hahn
In this study, in order to analyze the low-temperature sintering process of silver and copper nanoparticles, we calculate their melting temperatures and surface melting temperatures with respect to particle size. For this calculation, we introduce the concept of mean-squared displacement of the atom proposed by Shi (1994). Using a parameter defined by the vibrational component of melting entropy, we readily obtained the surface and bulk melting temperatures of copper and silver nanoparticles. We also calculated the absorption cross-section of nanoparticles for variation in the wavelength of light. By using the calculated absorption cross-section of the nanoparticles at the melting temperature, we obtained the laser threshold energy for the sintering process with respect to particle size and wavelength of laser. We found that the absorption cross-section of silver nanoparticles has a resonant peak at a wavelength of close to 350 nm, yielding the lowest threshold energy. We calculated the intensity distribution around the nanoparticles using the finite-difference time-domain method and confirmed the resonant excitation of silver nanoparticles near the wavelength of the resonant peak.
{"title":"Calculating the Threshold Energy of the Pulsed Laser Sintering of Silver and Copper Nanoparticles","authors":"Changmin Lee, J. Hahn","doi":"10.3807/JOSK.2016.20.5.601","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.5.601","url":null,"abstract":"In this study, in order to analyze the low-temperature sintering\u0000 process of silver and copper nanoparticles, we calculate their melting\u0000 temperatures and surface melting temperatures with respect to particle\u0000 size. For this calculation, we introduce the concept of mean-squared\u0000 displacement of the atom proposed by Shi (1994). Using a parameter defined\u0000 by the vibrational component of melting entropy, we readily obtained the\u0000 surface and bulk melting temperatures of copper and silver nanoparticles.\u0000 We also calculated the absorption cross-section of nanoparticles for\u0000 variation in the wavelength of light. By using the calculated absorption\u0000 cross-section of the nanoparticles at the melting temperature, we obtained\u0000 the laser threshold energy for the sintering process with respect to\u0000 particle size and wavelength of laser. We found that the absorption\u0000 cross-section of silver nanoparticles has a resonant peak at a wavelength\u0000 of close to 350 nm, yielding the lowest threshold energy. We calculated\u0000 the intensity distribution around the nanoparticles using the\u0000 finite-difference time-domain method and confirmed the resonant excitation\u0000 of silver nanoparticles near the wavelength of the resonant\u0000 peak.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"8 1","pages":"601-606"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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