• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.35.1-35.6
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• 2020

Background: Miescher's cheilitis granulomatosa (MCG) is a rare chronic inflammatory disease and is known as the monosymptomatic clinical form of Melkersson-Rosenthal syndrome (MRS). It is characterised by swelling of one or both lips and more frequently affects the upper lip. Histopathological findings show the presence of numerous inflammatory infiltrates and granuloma formations. Pharmacological treatments and surgery have provided results that are positive yet insufficiently stable in the long term. The clinical case described is of a 68-year-old female patient with a diagnosis of MCG of the upper lip. Case presentation: The patient was diagnosed and treated at the Oral Medicine and Oral Pathology outpatient clinic of Maxillofacial and Odontostomatology Unit, Fondazione Cà Granda IRCCS Ospedale Maggiore Policlinico. The patient was recommended localised treatments of photobiomodulation (PBM) using a diode laser with a 635 nm and 980 nm dual-wavelength (λ) approach, a 600-micron fibre, and a handpiece with a 1-cm-diameter lens at 300 mW. Three treatments a week were administered for four weeks for a total of 12 treatment sessions (T₁-T₁₂). After that, the patient had a long follow-up period of about 2 years. The therapeutic results were clear from the initial stages of treatment. There was an immediate, gradual, and consistent reduction in labial swelling. A reduction in the size of the lip by about 35% at T₁₀-T₁₂ was observed, returning the size and volume of the upper lip within the normal clinical range. The painful symptoms subsided after the seventh treatment (T₇). The histopathological check at 3 months and the follow-up in particular confirmed the disease was in remission with satisfactorily stable treatment results. Moreover, the patient did not use any other treatments on the area from the early laser treatments through to the end of the follow-up period. Conclusions: Our experience describes a clinical case of MCG treated with PBM and effectively resolved with a reduction of the lip swelling. The real success of the treatment emerged over time, showing that the tissue healing was stable. In absence of any collateral phenomena, this confirms the effective and documented therapeutic potential of PBM for chronic inflammatory infiltrates.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.2
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• pp.141-149
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• 2015

In the fabrication of electronic circuits used in electronic products, molybdenum thin films are deposited on semiconductors to prevent oxidation. During the deposition, the presence of a particle or dust at the interface between the thin film and substrate causes the decrease of adhesion, performance, and life cycle. In this study, a damage measurement targeting two kinds of glass substrate, with and without particles, was performed in order to measure the change in the molybdenum thin film deposition area in the presence of a particle. Clean and dirty molybdenum thin film specimens were fabricated and directly deposited on a substrate using the sputtering method, and a reflection-type digital holographic interferometer was configured for measuring the damage. Reflection-type digital holography has several advantages; e.g., the configuration of the interferometer is simple, the measurement range can be varied depending on the magnification of a microscopic lens, and the measuring time is short. The results confirm that reflection-type digital holography is useful for the measurement of the damage and defects of thin films.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.95-101
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• 1999

We have studied the 1.54$\mu\textrm{m}$ forward and backward stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SRS) for various $CH_4$pressures by 1.06$\mu\textrm{m}$ 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 $CH_4$gas uncirculating system, the output energy of the backward SRS and SBS were reduced the about 47% due to a thermal heating of $CH_4$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.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.213-220
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• 2017

This paper proposes how to fabricate an educational Mach-Zehnder interferometer that is easy to align and inexpensive, using 3D printers and semiconductor lasers. The interferometer consists of a body $165mm{\times}120mm{\times}57mm$ in size, mirror mounts, a laser holder, beam splitters, and so on. The laser path is adjusted by 4 mirror mounts, each comprised of rubber bands, small metal wires, and a screw. The interference fringe is enlarged by the lens at the final stage. The refractive index of a slide glass was measured by counting the number of moving interference fringes while the slide glass, inserted into one of the two interferometer arms, is rotating. The formula for the refractive index as a function of the optical-path difference and rotation angle was obtained, and used to calculate the refractive index of glass from the interferometer experiment. The use of a rotating glass in one arm of the interferometer nullifies the need for a precision stage, which despite its high cost is often required to observe the moving interference fringe in the classroom. Therefore, the 3D-printed Mach-Zehnder interferometer proposed in this paper can be very useful for education, because of its affordability and performance. It enables students to perform both qualitative and quantitative studies using a 3D-printed interferometer, such as measuring the refractive index of a glass sample, and the wavelength of light.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.53.2-53.2
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• 2015

Fiber Bragg gratings (FBGs) are the most compact and reliable method of suppressing atmospheric emission lines in the infrared for ground-based telescopes. It has been proved that real FBGs based filters were able to eliminate 63 bright sky lines with minimal interline losses in 2011 (GNOSIS). Inscribing FBGs on multi-core fibers offers advantages. Compared to arrays of individual SMFs, the multi-core fiber Bragg grating (MCFBG) is greatly reduced in size, resistant to damage, simple to fabricate, and easy to taper into a photonics lantern (PRAXIS). Multi-mode fibers should be used and the number of modes has to be large enough to capture a sufficient amount of light from the telescope. However, the fiber Bragg gratings can only be inscribed in the single-mode fiber. A photonic lantern bi-directionally converts multi-mode to single-mode. The number of cores in MCFBGs corresponds to the mode. For a writing system consisting of a single ultra-violet (UV) laser and phase mask, the standard writing method is insufficient to produce uniform MCFBGs due to the spatial variations of the field at each core within the fiber. Most significant technical challenges are consequences of the side-on illumination of the fiber. Firstly, the fiber cladding acts as a cylindrical lens, narrowing the incident beam as it passes through the air-cladding interface. Consequently, cores receive reduced or zero illumination, while the focusing induces variations in the power at those that are exposed. The second effect is the shadowing of the furthest cores by the cores nearest to the light source. Due to a higher refractive index of cores than the cladding, diffraction occurs at each core-cladding interface as well as cores absorb the light. As a result, any core that is located directly behind another in the beam path is underexposed or exposed to a distorted interference pattern from what phase mask originally generates. Technologies are discussed to overcome the problems and recent experimental results are presented as well as simulation results.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.98-105
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• 2001

The machining accuracy is affected by geometric, volumetric errors of the machine tools. To improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as error analysis of machine tools ahas been studied for last several decades. This paper suggests the enhancement method of machining accuracy for precision machining of high quality metal reflection mirror or optics lens, etc. In this paper, we study 1) the compensation of linear pitch error with NC controller compensation function using laser interferometer measurement, 2) the method for enhancing the accuracy of NC milling machining by modeling and compensation of volumetric error, 3) the spherical surface manufacturing by modeling and compensation of volumetric error of the machine tool, 4) the system development of OMM without detaching work piece from a bed of machine tool after working, 5) the generation of the finished part profile by OMM. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.174-181
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• 2001

Nowadays, the improvement and development of Multi-media and information & communication technology is rapidly processed. They need large data storage capacity. So that, many studies and researches in data storage have been carried out. According to them, the data storage capacity has been increased. But the limitation of storage capacity is happened for several problems. One of them is spot & pit size in optical and magnetic data storage and another is the resolution of actuators. The problems in spot & pit size are covered by new data storage methods-- for examples, AFM(Atomic Force Microscopy), MO(Magneto-optical) system, and NFR(Near-Field decoding) system etc. But the resolution limit of an actuator was not developed and doesn\`t follow up the development of spot & pit size. Because of them, we should improve a resolution of an actuator. Especially, in this paper an actuator if studied and designed for NFR (in using SIL(Solid Immersion Lens) system. It is a dual stage actuator, which consists of a Fine actuator and a Coarse actuator. and should desire 100nm accuracy. Its actuating force generation method is VCM(Voice Coil Motor). The Fine actuator is composed of 4-leaf springs and a bobbin wrapped by coil. The Coarse actuator has Coils and 3-Roller bearings. Also, The Characteristics of designed actuator for NFR system is estimated by Sine-Swept mode and LDV(Laser Doppler Vibro-meter).

• Journal of the Korean Society of School Health
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• v.12 no.1
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• pp.71-84
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• 1999

This study attempts to identify the self-image of eyeglass wearers with Q-methodology. Preliminary Q-statements were collected through personal and telephone interviews and based in consultation with reference books, eyeglass wearers, an optician and an oculist. Finally, 34 Q-samples were seleted. The results were analyzed by a Q-factor with a PC QUANL Program. The self-image of eyeglass wearers were found to revolve around three types: Type 1. They feel that eyeglasses have a negative influence on image and that they uncomfortable. In addition, other people have a negative bias toward people who wear eyeglasses. As a result of these negative prejudices and inconveniences, there is a tendency to wear contact lens or have laser operations. Type 2. They feel less uncomfortable comparatively, when explained that glasses can help improve their image. When explained as a fashion accessory, negative prejudices almost disappeared. Type 3. They show a positive reaction when explained that spectacles are also used for sight protection. Howerer, they are sensitive to changes in their complexion as a result of eyeglass wear and place much importance in the design of glass frames. The significance of this study is to suggest basic data for a mediation device that improve the image of eyeglass wearers discovery and analysis of these three types.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.103-103
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• 2014

Manufacturing of lens and mirror using Diamond Turning Machine (DTM) offers distinct advantages including short fabrication time and low cost as compared to grinding or polishing process. However, the DTM process can leave mid-frequency error in the optical surface which generates an undesirable diffraction effect and stray light. The mid-frequency error is expected to be eliminated by mechanical polishing after the DTM process, but polishing of soft surface of ductile aluminum is extremely difficult because the polishing process inevitably degrades the surface form accuracy. In order to increase its surface hardness, we performed electroless nickel plating on the surface of diamond-turned aluminum (Al-6061T6) off-axis mirrors, which was followed by the 6-hour-long baking process at $200^{\circ}C$ for improving its hardness. Then we polished the nickel plated off-axis mirrors to remove the mid-frequency error and measured polished mirror surfaces using the optical surface profilometer (NT 2000, Wyko Inc.). Finally, we ascertained that the mid-frequency error on the mirror surface was successfully removed. During the whole processes of nickel plating and polishing, we monitored the form accuracy using the ultra-high accurate 3-D profilometer (UA3P, Panasonic Corp.) to maintain it within the allowable tolerance range (< tens of nm). The polished off-axis mirror was optically tested using a visible laser source and a pinhole, and the airy pattern obtained from the polished mirror was compared with the unpolished case to check the influence of mid-frequency error on optical images.

• Polymer(Korea)
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• v.29 no.4
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• pp.418-421
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• 2005

Three-dimensional (3D) microfabrication process using two-photon polymerization (TPP) is developed to fabricate the curved microstructures in a layer, which can be applied potentially to optical MEMS, nano/micro-devices, etc. A 3D curved structure can be expressed using the same height-contours that are defined by symbolic colors which consist of 14 colors. Then, the designed bitmap figure is transformed into a multi-exposure voxel matrix (MVM). In this work a multi-exposure voxel matrix scanning method is used to generate various heights of voxels according to each laser exposure time that is assigned to the symbolic colors. An objective lens with a numerical aperture of 1.25 is employed to enlarge the variation of a voxel height in the range of 1.2 to 6.4 um which can be controlled easily using the various exposure time. Though this work some 3D curved micro-shapes are fabricated directly to demonstrate the usefulness of the process without a laminating process that is generally required in a micro-stereolithography process.