• The monthly packaging world
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• s.295
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• pp.71-76
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• 2017

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.68-68
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• 2000

In this paper a very brief review of historical development of optical science and technology in China is presented. More attention has been pain on Modem Optics, which developed since 1950s. The recent development of optical science and technology in following fields are introduced. 1. Optical engineering and instrumentation (tracking theodolites, high speed cameras, satellite laser ranging systems, satellite flying attitude control, cameras for remote sensing, astronomical optical instrument) 2. Applied optics (adaptive optics, optical metrology, infrared optics, optical processing, optical holography) 3. Laser science and technology (ultrashort pulse lasers, UV-X ray lasers, high power laser facilities and laser fusion, laser isotope separation) 4. Laser and nonlinear materials (rare earth elements doped laser glasses and crystals, tunable laser crystals, borate series and organic nonlinear crystals) 5. Optoelectronic science and technology (Optical communication, optical data storage, optical computing) The current situation and developing prospect of optical and optoelectronic industry in China are presented. Furthermore it points out that the optical industry could be developed vigorously only if products development capacity is enhanced and new products industrialization is heightened. The main research and education institutions in the optics field in China, as well as the Chinese Optical Society (COS) are introduced.

• Medical Lasers
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• v.10 no.3
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• pp.138-145
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• 2021

Low-level laser therapy or photobiomodulation (LLLT/PBM) therapy has been widely applied to enhance and accelerate the recovery of oral mucositis. This study investigates the documented effect of LLLT on oral mucositis caused by chemotherapy. This review appraises 6 animal studies and 12 clinical studies published in the Pubmed database during the past 10 years, related to the application of LLLT for the treatment of mucositis. Despite varied parameters and diverse conditions, the assessed articles indicate that application of LLLT on oral mucositis using near-infrared wavelengths is prophylactic, reduces pain, and enables a rapid recovery. Various combined treatments were also identified among the published papers, which further establishes the efficacy of LLLT as a viable treatment.

• Journal of Oral Medicine and Pain
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• v.18 no.2
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• pp.97-106
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• 1993

This study was performed to investigate the effects of infrared and visible light laser irradiation on cell viability of human gingival fibroblast. For the present study, the author used cultured fibroblast originated from sound gingiva which were fifth of sixth passage. Laser machine utilized here were stomalaser which irradiate infrared (GaAs diode) and red (HeNe) laser in turn with pulse wave pattern or continuous wave pattern, and the machine had several frequency mode presented by regeneration, relaxation and analgesic modalities. Cultured fibroblast samples were divided by this modalities of cell counts and laser exposure time which were 7-seconds of 150 seconds, respectively. 1 day after laser irradiation, each cell-well was treated with MTT and measured optical density with ELISA. The obtained results were as follows : 1. There was a tendency of increasing optical density in proportion to irradiation time in groups of $1\times10^4$ cell per well but in groups of $5\times10^3$ cell per well, reverse phenomena were observed. 2. The difference of optical density according to frequency modalities were not showed significantly except several cases in groups of $5\times10^3$ cell per well. 3. In general, cell viability of cultured human gingival fibroblast wer not showed consistent feature by low level laser irradiation.

• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.565-572
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• 2001

At the most recent years, laser medical instruments, laser applications and laser nuclear fusion need strong visible light and ultraviolet rays. Nonlinear optical devices, such as harmonic generators and parametric oscillators, provide a means of extending the frequency range of available laser sources. Frequency conversion is a useful technique for extending the utility of high-power lasers. It utilizes the nonlinear optical response of an optical medium in intense radiation fields to generate new frequencies. These progresses have been used to generate high-power radiation in all spectral regions, from the ultraviolet to the far infrared. Optical parametric oscillators and amplifiers generate two waves of lower frequency They are capable of generating a range of wavelengths from a single frequency source, in some cases spanning the entire visible and near infrared regions. Consequently, in order to obtain the green light, the pulsed Nd:YAG laser using multiple-mesh PFN(Pulsed Forming Network) method with Nonlinear optical device was adopted. We compared the current pulseshapes with the laser output energy, and conversion efficiency.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.20-26
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• 2014

Objective: The low level lasers currently in the market vary in wavelength, dosage, and frequency. These devices are used with much different clinical pathology. Most notably, some studies claim that wounds heal faster with low level laser therapy due to the fact that bacteria commonly found in wounds are killed by laser light. Systemic and meta-analysis studies found the difficulty of comparison of numerous research studies because of differences in the intensities and frequencies of low level laser treatment (LLLT). The purpose of this study was to determine the effectiveness of LLLT on controlling bacterial growth. Design: Cross-sectional study. Methods: Variables included LLLT dosage and wavelength on 3 bacteria commonly seen in wounds, strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were used on commercially available 5.0-cm agar plates. Blue, green, and red, ultraviolet (UV) and infrared laser light sources were adjusted to either low or high intensity settings. Five Petri dishes at a time were placed directly beneath laser light sources with the exception of UV which was placed six inches below the suspended light and infrared which was placed directly on top of the Petri dish lid. Each group of five Petri dishes was irradiated for 15 minutes. Results: The results showed no effect of any of 9 different LLLT intensities or colors on bacteria growth compared to sham light. Conclusions: At least for claims of bacterial growth inhibition with LLLT, no support for this claim can be found here.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1905-1907
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• 1997

The experiments of laser-guided de discharge were carried out by using pulsed Nd:YAG laser radiation at low air pressure ranging from 0.3 to 20 torr. The minimum laser-guided de discharge voltages($V_{MD}$) at given pressure and distances between anode and cathode electrode were obtained. In order to generate TEM(transverse electromagnetic waves) modes, a pinhole was installed between a rod and a half mirror, and its diameter was adjusted from 6mm to 1.7mm. And then, we investigated the characteristics of laser-guided de discharge corresponding to different TEM modes. As a result, it was found that $V_{MD}$ at $TEM_{00}$ mode was lower than $V_{MD}$ at multimodes.

• Journal of Welding and Joining
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• v.23 no.5
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• pp.55-60
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• 2005

A precise bonding technique, transmission laser bonding using energy transfer, for polymer micro devices is presented. The irradiated IR laser beam passes through the transparent part and absorbed on the opaque part. The absorbed energy is converted into heat and bonding takes place. In order to optimize the bonding quality, the temperature profile on the interface must be obtained. Using optical measurements of the both plates, the absorbed energy can be calculated. At the wavelength of 1100nm $87.5\%$ of incident laser energy was used for bonding process from the calculation. A heat transfer model was applied for obtaining the transient temperature profile. It was found that with the power of 29.5 mW, the interface begins to melt and bond each other in 3 sec and it is in a good agreement with experiment results. The transmission IR laser bonding has a potential in the local precise bonding in MEMS or Lab-on-a-chip applications.

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.214-220
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• 1990

We have studied the Infrared Multiphoton Dissociation (IRMPD) of 1-bromo-3-chloropropane by using the pulsed $CO_2$ laser. The product yields and the HCl/HBr branching ratios in IRMPD of $BrCH_2CH_2CH_2Cl$ are studied under the focused beam geometry as a function of buffer gas (He) pressure, laser energy, and photolysing wavelength. It is observed that the total dissociation yield has a laser energy dependence of 1.8-2.0 power order and the branching ratio is very slightly dependent on the pulse energy for the laser lines employed. The dependences of total dissociation yield and branching ratio on the buffer gas pressures show that the dissociation yield monotonically decreases and the branching ratio slightly decreases with the increase of the buffer gas pressure. The Energy-Grained Master Equation (EGME) was applied to explain the laser pulse energy and the buffer gas pressure(He) dependence of the dissociation yield and the branching ratio.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.169-173
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• 2007

During laser irradiation, mechanically deformed cartilage undergoes a temperature dependent phase transformation resulting in accelerated stress relaxation. Clinically, laser-assisted cartilage reshaping may be used to recreate the underlying cartilaginous framework in structures such as ear, larynx, trachea, and nose. Therefore, research and identification of the biophysical transformations in cartilage accompanying laser heating are valuable to identify critical laser dosimetry and phase transformation of cartilage for many clinical applications. quasi-elastic light scattering was investigated using Ho : YAG laser $(\lambda=2.12{\mu}m\;;\;t_p\sim450{\mu}s)$ and Nd:YAG Laser $(\lambda=1.32{\mu}m\;;\;t_p\sim700{\mu}s)$ for heating sources and He : Ne $(\lambda=632.8nm)$ laser, high-power diode pumped laser $(\lambda=532nm)$, and Ti : $Al_2O_3$ femtosecond laser $(\lambda=850nm)$ for light scattering sources. A spectrometer and infrared radiometric sensor were used to monitor the backscattered light spectrum and transient temperature changes from cartilage following laser irradiation. Analysis of the optical, thermal, and quasi-elastic light scattering properties may indicate internal dynamics of proteoglycan movement within the cartilage framework during laser irradiation.