• Journal of Periodontal and Implant Science
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• v.40 no.3
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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.

• Proceedings of the Optical Society of Korea Conference
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• 2001.08a
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• pp.160-161
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• 2001

A diode laser system has been developed for the refractory glaucoma therapy. The diode lasers have merits in clinical usage including reduction of beam dispersion, higher absorption such as in melanin pigment, and lower complication in treatment. We present the system specification of laser diodes in 810mm with 3W power, which is delivered into the optical fiber core of 600${\mu}{\textrm}{m}$.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.42-51
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• 2012

In this paper, injection-locking characteristics versus active layer structures in Fabry-Perot laser diodes (FP-LD) are compared. TE and TM gain spectra and peak gains versus carrier density in polarized and unpolarized multiple quantum well structures and in an unpolarized bulk structure are calculated. The calculated gain parameters are applied to a time-domain large-signal model to simulate the injection-locking characteristics. The results show that RIN in unpolarized FD-LDs is about 3 dB lower than that in a polarized FP-LD and that the eye characteristics of the unpolarized FP-LD are much better than those of the polarized FP-LD.

• Investigative and Clinical Urology
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• v.59 no.6
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• pp.392-398
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• 2018

Purpose: To evaluate the initial experience and outcome of photo-selective vaporization of the prostate (PVP) for benign prostatic hyperplasia (BPH) in Pakistan with the use of a 980 nm diode laser. Materials and Methods: A prospective study was performed from November 2016 to December 2017. A total of 100 patients diagnosed with bladder outlet obstruction secondary to BPH who planned for PVP were enrolled in the study. PVP was carried out with a diode laser at 980 nm (Biolitec Diode 180W laser) in a continuous wave with a 600 nm (twister) fiber. Baseline characteristics and perioperative data were compared. Postoperative outcomes were evaluated by International Prostate Symptom Score (IPSS), post void residual (PVR) and maximum urinary flow rate (Qmax) at 3 and 6 months after surgery. Results: The mean age was $65.82{\pm}10.42$, mean prostate size was $67.35{\pm}16.42$, operative time was $55.85{\pm}18.01$ and total energy was $198.68{\pm}49.12kJ$. At 3 months and 6 months, significant improvements were noted (p<0.001) in IPSS $7.04{\pm}1.69$ (-18.92), Qmax $19.22{\pm}4.75mL/s$ (+13.09) and and PVR $18.89{\pm}5.39mL$ (-112.80). Most frequent problems were burning micturition (35%) and terminal dysuria (29%). No significant difference in postoperative hemoglobin was seen in patients who were on anti-platelet drugs. Conclusions: PVP with a diode laser is a safe and effective procedure for the treatment of BPH and is also safe in patients who are on anti-platelet agents.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.05a
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• pp.171-175
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• 1995

Semiconductor diode lasers that can generate one watt or more of optical energy for tens of milliseconds (quasi continuous wave) are now readily available. Several researchers have demonstrated that this power level, when properly coupled, can reliably initiate pyrotechnic mixtures. This means that the initiator containing the pyrotechnic can be protected against inadvertent initiation from electromagnetic radiation or electrostatic discharge by a conducting Faraday cage surrounding the explosive. Only a small dielectric window penetrates the housing of the initiator, thereby eliminating the conductors necessitated by a bridgewire electroexplosive device. The diode laser itself, however, functions at a low voltage (typically 3 volts) and hence is susceptible to inadvertent function from power supply short circuits, electrostatic discharge or induced RF energy. The rocket motor arm-fire device de-scribed in this paper uses a diode laser, but protects it from unintentional function with a Radio Frequency Attenuating Coupler (RFAC).The RFAC, invented by ML Aviation, a UK company, transfers power into a Faraday cage via magnetic flux, thereby protecting the diode, its drive circuit and the pyrotechnic from all electromagnetic and electrostatic hazards. The first production application of a diode laser and RFAC device was by the Korean Agency for Defense Development.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.945-947
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• 2009

We developed a new laser irradiation (BLDA: Blue Multi-Laser-Diode Annealing) system. The system forms the uniform line beam, which is constructed by 48 pieces of semiconductor lasers. This new system has achieved high laser output stability and the highly accurate beam shape by adopting a reliable laser control, the auto-focus control in addition to an original laser photosynthesis technology and the beam homogenizing technology. It was confirmed to crystallize the Si films effectively with good quality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.654-659
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• 2011

We propose a novel method to reduce laser chirp and improve modulation performance in semiconductor laser by using dual-electrode structure. Dual-electrode structure is realized by segmenting a electrode on top of gain medium, as was the case of edge emitting laser diode, into electrically isolated two electrodes. By using the proposed structure, we have experimentally achieved a reduction of laser spectral width of 0.23 nm and an improvement of 2.5-dB receiver sensitivity at an 80-km fiber transmission for 10-Gbps NRZ (non-return-to zero) data stream.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.396-399
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• 2002

Using a bi-layer anti-reflection coating of $TiO_2$and $SiO_2,$ we have achieved a minimum facet reflectivity of $~10^{-5}$ and a band width of 27 nm for a reflectivity of $~10^{-4}$ or less for 1.3 $\mu\textrm{m}$ spot size converter integrated semiconductor lasers. This coating is applicable to external-cavity-tuned laser sources and semiconductor optical amplifiers.

• Journal of the Semiconductor & Display Technology
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• v.7 no.4
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• pp.19-22
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• 2008

Thin film has been an increasing important subject of intensive research, owing to the fact that these films possess desirable optical, electrical and electrochemical properties for uses in many semi-conducting nano-crystal applications, such as light-emitting diodes, lasers and solar cell applications. Here, ZnSe thin films were deposited by electrochemical method for the applications of light emitting diode. Electrochemical deposition of ZnSe thin film is not easy, because of the high difference of reduction potential between zinc ion and selenium acid. In order to handle the band gap of ZnSe crystal thin films easily, electrochemical methods are promising to manufacture these films economically. Therefore we have investigated the present study to characterize zinc selenide thin films deposited on ITO glass plates electrochemically. The luminescent properties of ZnSe films have been evaluated by UV-Vis spectrometer and luminescence spectrometer. And the morphology of the film surface has been discussed qualitatively from SEM images.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.666-672
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• 2003

In this paper, we described the fabrication and the performance of wavelength tunable distributed bragg reflector (DBR) laser diode (LD), having different waveguide coupling mechanisms; integrated-twin-guide (ITG) DBR-LD and butt coupled (BT) DBR-LD. This deviceis fabricated by metal organic vapor phase epitaxy (MOVPE) growth and planar buried heterostructure (PBH)-type transverse current confinement structure. The result of measurement, the optical performance of BT-DBR-LD is better over 2 times than that of ITG-DBR-LD at the variation of threshold current and output power, and slop efficiency due to the higher coupling efficiency of the butt coupled structure than the integrated twin guide structure. The maximum wavelength tuning range is about 7.2nm for ITG DBR-LD and 7.4nm for BT DBR-LD. Both types of lasers have a very high yield of single mode operation with a side-mode suppression ratio of more than 35dB.