• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.122-122
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• 2013

In this talk, some optical properties of quantum dot based mode-locked diode lasers and photonic crystal nano lasers will be discussed. Linewidth enhancement factor, chirp and interband injection locking technique of quantum dot mode-locked lasers will be presented. Also various types of photonic crystal buried heterostructure lasers toward coherent nano laser will be covered as well.

• 대한화학회지
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• 제38권1호
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• pp.34-40
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• 1994

다이오드 레이저를 optogalvanic spectroscopy에 이용하여 우라늄, 토륨 및 루비듐에 대한 전자전이 및 다이오드 레이저의 분광학적 특성을 살펴보았다. 흡수스펙트럼의 분석은 속빈 음극관내 음극표면에서 튕김에 의해 형성된 고온의 금속원자 기체를 다이오드 레이저를 이용하여 금속원자의 광흡수 현상에 따른 임피던스의 변화를 측정함으로써 수행되었다. 다이오드 레이저를 사용하여 자연산 악티늄족 원소인 토륨과 우라늄의 검출을 수행하였다. 본 실험에 이용된 optogalvanic spectroscopy에서는 Doppler효과로 인한 띠 나비에 제한이 있어 초미세 갈라짐이나 동위원소 선이동을 관찰하는데 어려움이 있었다. 하지만 루비듐 780.023 nm에서는 Doppler 띠 넓힘이 있음에도 불구하고 동위원소의 선이동과 초미세 갈라짐을 관찰할 수 있었다. 본 연구에서는 다이오드 레이저가 방사능을 지닌 악티늄족 원소들의 검출과 이들의 동위원소 존재비를 측정할 때 유용하고, 별로 알려지지 않은 란탄족 및 악티늄족의 초미세 갈라짐 상수와 같은 분광학적으로 중요한 파라미터를 구하는데에도 긴요하게 쓰일 수 있음을 고찰하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1986년도 하계학술대회논문집
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• pp.609-613
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• 1986

The resonance frequency and the gain for oscillation of external cavity diode lasers are derived by approximating the phase and the gain conditions. By modifying single mode rate equations for the external cavity diode laser, steady state solutions and their stability are studied.

• Journal of Periodontal and Implant Science
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• 제53권5호
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• pp.376-387
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• 2023

Purpose: Peri-implantitis (PI) is an inflammatory condition associated with the destruction of bone tissue around a dental implant, and diode lasers can be used to treat this disease. In this study, we aimed to evaluate the effectiveness of a 940-nm diode laser for the nonsurgical treatment of PI. Methods: Twenty patients (8 women and 12 men) were enrolled in a split-mouth randomized controlled study. In the control group (CG), mechanical debridement with titanium curettes accompanied by airflow was performed around the implants. The test group (TG) was treated similarly, but with the use of a diode laser. Clinical measurements (plaque index, gingival index [GI], probing pocket depth [PPD], bleeding on probing [BOP], clinical attachment level, and interleukin-1β [IL-1β] in the peri-implant crevicular fluid) were evaluated and recorded at baseline and 3 months. IL-1β levels were determined using the enzyme-linked immunosorbent assay method. Results: The symptoms were alleviated in both groups at 3 months as assessed through clinical measurements. GI, BOP, and PPD were significantly lower in the TG than in the CG (P<0.05). The IL-1β level increased post-treatment in both groups, but this increase was only statistically significant (P<0.05) in the CG. Conclusions: The diode laser enabled improvements in clinical parameters in the periimplant tissue. However, it did not reduce IL-1β levels after treatment. Further studies about the use of diode lasers in the treatment of PI will be necessary to evaluate the effects of diode lasers in PI treatment.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.220-221
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• 2003

Intracavity second harmonic generation of diode pumped solid state lasers in the visible and ultraviolet regions provide efficient, compact and robust light sources for various applications, such as optical data storage, material processing, spectroscopy and bioanalysis. Advantages of neodymium vanadate (Nd：$YVO_4$) as a gain medium for intracavity-doubled lasers over Nd：YAG lie in the facts that the gain spectrum consists of a single line with short absorption depth, and that the stimulated emission cross sections are larger. (omitted)

• Journal of the Optical Society of Korea
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• 제6권3호
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• pp.108-116
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• 2002

Lasing modes of laser-diode-pumped fiber grating lasers are analyzed by coupled-mode theory. First, a power series solution of the coupled-mode equations is derived under the assumption of an exponentially-decreasing longitudinal modal gain profile for a laser-diode-pumped grating section, followed by determination of the transfer matrix for such a section. Based on these results, an eigenvalue equation for oscillation is then derived and solved numerically for the lasing modes of uniform and phase-shifted fiber grating lasers. Comparisons made with the uniform-gain results indicate that, surprisingly, the lasing mode characteristics are not as significantly altered as might be expected in most cases, even for a highly nonuniform gain profile. In the case of a phase-shifted grating, the phase-shift position appears to have a much greater impact on determining the threshold gain, the modal field distribution, and the front-to-back output power ratio.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.3123-3123
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• 2001

Near infrared (NIR) spectroscopy has become a widely used method in food and beverage analysis because of its speed, accuracy and the simplicity of sample preparation. One of the basic requirements of NIR instruments is a wide dynamic range if weak, or small, absorption changes or concentrations are to be measured. Thus the instrument must be sufficiently luminous, and efficient, to enable measurements to be made in a reasonably short time, as for some applications (e.g. sorting) short response times are essential. Diode lasers function the same way as lasers but linewidths are not as narrow as typical lasers. In this work an array of seven laser diodes (in the range of 750-1100 nm) with energy outputs of around hundred milliwatts each were combined with a fast diode array spectrometer (400-1100 nm, 1024 pixels, integration time from 3 ms) as detector. Measurements in transmission mode were performed in solutions of sugars in aqueous solutions and in deuteriumoxide. The feasibility of non-destructive measurements in transmission mode was investigated for different fruits and vegetables.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.54-57
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• 1987

A new method optical short pulse generation using diode lasers under the negative electro-optic feedback are proposed. The self-pulsing is induced by feedback itself and the pulse is formed by the interaction of feeback signal and the dynamics of the diode laser. The simulated pulse width is on the order of picosecond with several GIIz repetition rates.

• Journal of Periodontal and Implant Science
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• 제40권3호
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• pp.105-110
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• 2010

Purpose: It has been reported that low-level semiconductor diode lasers could enhance the wound healing process. The periodontal ligament is crucial for maintaining the tooth and surrounding tissues in periodontal wound healing. While low-level semiconductor diode lasers have been used in low-level laser therapy, there have been few reports on their effects on periodontal ligament fibroblasts (PDLFs). We performed this study to investigate the biological effects of semiconductor diode lasers on human PDLFs. Methods: Human PDLFs were cultured and irradiated with a gallium-aluminum-arsenate (GaAlAs) semiconductor diode laser of which the wavelength was 810 nm. The power output was fixed at 500 mW in the continuous wave mode with various energy fluencies, which were 1.97, 3.94, and 5.91 $J/cm^2$. A culture of PDLFs without laser irradiation was regarded as a control. Then, cells were additionally incubated in 72 hours for MTS assay and an alkaline phosphatase (ALPase) activity test. At 48 hours post-laser irradiation, western blot analysis was performed to determine extracellular signal-regulated kinase (ERK) activity. ANOVA was used to assess the significance level of the differences among groups (P<0.05). Results: At all energy fluencies of laser irradiation, PDLFs proliferation gradually increased for 72 hours without any significant differences compared with the control over the entire period taken together. However, an increment of cell proliferation significantly greater than in the control occurred between 24 and 48 hours at laser irradiation settings of 1.97 and 3.94 $J/cm^2$ (P<0.05). The highest ALPase activity was found at 48 and 72 hours post-laser irradiation with 3.94 $J/cm^2$ energy fluency (P<0.05). The phosphorylated ERK level was more prominent at 3.94 $J/cm^2$ energy fluency than in the control. Conclusions: The present study demonstrated that the GaAlAs semiconductor diode laser promoted proliferation and differentiation of human PDLFs.

• 한국광학회지
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• 제23권5호
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• pp.227-232
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• 2012

본 논문에서는 RLD (Reflective Laser Diode)와 FBG (Fiber Bragg Grating)가 하이브리드 집적된 LD (이하 FG-LD)의 정적 및 동적 특성을 해석하기 위하여 대신호 시영역 모델링 방법을 구현하였다. FBG의 유효길이 2.1 mm를 포함한 외부 집적 공진기의 길이가 8 m인 경우에 0.44GHz의 동적 주파수 요동과 6.4 GHz 정도의 동적 주파수 요동 결과를 나타내었다. 또한 10 Gbps NRZ 신호의 아이가 크게 오픈된 상태를 잘 유지함을 확인하였다. FG-LD는 50 km 정도의 길이를 커버하는 10 Gbps 급 단일파장 레이저로서의 효용성이 있을 것으로 기대된다.