Diode Lasers

www.hplsa2018.com

On behalf of the Organizing Committee, we extend a warm and cordial welcome to you to be part of 22th Symposium on High Power Laser Systems and Applications, held conjointly with eminent researchers and scholars from all around the globe during October 9 - 12, 2018 in the amazing venue of Villa Mondragone, Frascati, near Rome, Italy.
You can be a part of this event by participating as a speaker by giving oral presentation or you can give poster presentation in your area of expertise.
Selected papers will be published in the Proceedings published by SPIE.
The conference will also provide delegates with the opportunity to consolidate their knowledge and understanding of the latest scientific advancements on laser systems and their applications.

Welcome in Frascati!

Lasers are a relatively new addition to the orthodontist's armamentarium. This article reviews the fundamental basic science of available soft-tissue lasers, with an emphasis on diode lasers, and discusses various adjunct applications of the diode laser for soft-tissue orthodontic procedures. Diode lasers function by cutting with an initiated hot tip and produce minimal to no interaction with healthy dental hard tissue, making them suitable for soft-tissue procedures. The contact cutting mode provides enhanced bloodless site visibility and facility to perform delicate soft tissue procedures, which is important in areas with difficult access. Such adjunctive uses include laser gingivectomy to improve oral hygiene or bracket positioning, esthetic laser gingival recontouring, and laser exposure of superficially impacted teeth. Selected cases treated with a 940-nm indium-gallium-arsenide-phosphide (InGaAsP) diode laser will be presented.

LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. Over the years, lasers have advanced imperceptibly in our day to day life from recording price of groceries to laser guided warfare. Lasers saw the light of day due to Ted Maiman in 1960 but it was not until 1980’s that lasers saw their use in dental clinical practice. This article reviews the uses of diode lasers in dentistry.

二極體雷射又稱作軟組織雷射，因其擁有牙齦手術切割的能力，裝置尺寸小且費用相對較低，在部分臨床牙醫師之間已漸漸風行。軟組織雷射的防潮控制(moisture control)與止血(hemostasis)的能力，使臨床牙醫師切割牙齦組織、施行美觀性牙冠增長術(esthetic crown lengthening)、與降低牙齦溝(gingival troughing)等術式容易上手，讓臨床牙醫師們對於雷射手術技術的操作更容易熟悉。軟組織雷射在牙科領域中也漸漸被接受，他們有潛力在降低生物性副作用的情況下，完成贗復前牙齦處理。這篇文章強調了二極體雷射於上顎前牙的牙周-贗復技術中的使用。針對他們臨床優點的評估，討論其使用在美容牙科治療的好處。

Multilevel inverters have already gained high popularity among research teams as well as in production of high and medium-voltage applications for industrial purposes over the period of twenty years. Moreover, multilevel inverters are able to generate switched waveforms with reduced levels of harmonic sag compared to a conventional converter. Recent increased interest in multilevel inverters is due to their ability to generate high quality output waveforms at lower switching frequencies; the multilevel topology used in dynamic voltage restorer works towards the reduction of the total harmonic distortion counting all of the losses at the output end. This paper provides a new topology for the modulation in the multilevel inverter using switched capacitor. The self-balancing capability for the capacitor voltage and the SC connected in parallel so as to provide the voltage setup. The methodology presented works towards minimizing the THD by implementing the 9 level MLI and comparing the same to the other level in terms of distortion. The factors like cost are also considered in the design for which half bridge is being used.

Compact, tunable, low-power consumption coupled-cavity lasers are designed and experimentally demonstrated. Single-mode operation with an SMSR >24 dB and >11 nm tuning range are achieved, being suitable as on-chip local oscillators in low-power integrated optical coherent receivers.

The aim of this study was to present a case report of surgical removal of hyperplasia in the oral cavity using diode laser
radiation and rehabilitation with a complete denture. Epulis fissuratum is a pseudotumor growth located over the soft tissue
of the vestibular sulcus caused by the chronic irritation from the poorly adapted dentures. The case discussed in the present
study reported with the massive fibrous mass (5x2x1 cm) with multiple folds located in the maxillary vestibular sulcus
extending bilaterally from canine to canine region. This massive lesion was excised using diode laser and new complete
dentures with proper peripheral extensions were fabricated and delivered to the patient. Patient was kept on regular follow
up and clinical examination revealed normal vestibular mucosa and functionally sufficient prosthesis.
Keywords: Epulis Fissuratum; Diode Laser; Hyperplastic; Ill Fitting Dentures.

A frenum is a soft tissue attachment of the labial, buccal and lingual mucosa to the jaw bones. Abnormalities in development of this soft tissue fold may present as a very short lingual frenum limiting the mobility of the tongue. This condition is termed as ankyloglossia or tongue tie. The surgical technique is used to reposition the frenum and correct the functional impairments caused by ankyloglossia. This case report presents a 30 years old male patient with impairment of speech due to the short lingual frenum. 980 nm diode laser was used for frenectomy which showed minimal pain and healing with no complications. Surgical procedures like frenectomy and biopsy of oral lesions can be effectively carried out using Diode laser.

A laser safety analysis for liquid-crystal–on–silicon (LCOS) based imaging projection systems
utilizing laser light sources is presented. It is shown that a typical laser-based imaging projector
is capable of providing a D65 white-balanced luminous flux in excess of 20 lm while remaining Class
1 eye safe. By considering a Class 2 classification, it is shown that the same architecture is capable of
providing several hundred lumens, a performance level which could potentially be applicable to a
new class of high-brightness miniature projection systems.

Aim: This study aims to evaluate the bacterial reduction after conventional root canal treatment using 5.25% sodium hypochlorite. Materials and Methods: The study criteria included 100 patients requiring root canal treatments due to pulpitis. The diagnosis was made based on objective clinical signs (examination, probing, percussion, palpation) and X-ray investigation. The clinical procedures were carried out under strict aseptic precautions. All patients were subjected to biomechanical preparation followed by irrigation using sodium hypochlorite at a concentration of 5.25% which is considered the highest concentration without causing any toxic effect on the patient. All microbiological samples were taken immediately after the access preparation baseline (S1) and after the completion of the root canal instrumentation and disinfection with 5.25% sodium hypochlorite (S2) and sent for microbiological analysis. Results: One hundred patients with infected root canal were selected for this in vivo study. All S1 samples were positive for microbial isolates, 71 samples harbored cultivable bacterial isolates, 22 were fungus (Candida albican), and 7 samples showed no growth so in total adding up to 151 isolates identified from 100 patients. Bacterial isolates before chemomechanical treatment showed the highest prevalence belonging to Enterococcus faecalis followed by Streptococci, Staphylococci and Candida albican. After the chemomechanical treatment with 5.25% of sodium hypochlorite no cultivable bacteria were isolated from 38 patients root canals, and therefore the treatment managed to eradicate 54% of the 151 isolated bacterial species from the 71 infected root canals. Conclusion: The antimicrobial effect of 5.25% sodium hypochlorite was effective in eradicating a high number of the bacterial isolates along with the fungus identified in infected root canals. This high concentration of sodium hypochlorite presented no toxic damage to the root canal or the area around it when handled with care.

A 1064 nm wavelength laser was obtained by pumping a Nd:YVO4 crystal using a 808 nm wavelength diode laser. A curved and a flat mirror were used to examine two different cavity mirrors. The Q-switching of this laser was realized using a saturable absorber. Second harmonic generation was performed to obtain both continuous wave and Q-switched 532 nm wavelength laser.

— The efficiency limiting mechanisms in type-I GaInAsSb-based quantum well (QW) lasers, emitting at 2.3 µm, 2.6 µm and 2.9 µm, are investigated. Temperature characterization techniques and measurements under hydrostatic pressure identify an Auger process as the dominant non-radiative recombination mechanism in these devices. The results are supplemented with hydrostatic pressure measurements from three additional type-I GaInAsSb lasers, extending the wavelength range under investigation from 1.85-2.90 μm. Under hydrostatic pressure, contributions from the CHCC and CHSH Auger mechanisms to the threshold current density can be investigated separately. A simple model is used to fit the non-radiative component of the threshold current density, identifying the dominance of the different Auger losses across the wavelength range of operation. The CHCC mechanism is shown to be the dominant non-radiative process at longer wavelengths (> 2 μm). At shorter wavelengths (< 2 μm) the CHSH mechanism begins to dominate the threshold current, as the bandgap approaches resonance with the spin-orbit split-off band.

We present a novel implementation of the “phase reconstruction using optical ultra fast differentiation” (PROUD) technique and apply it to characterize the time resolved chirp of a gain switched semiconductor laser. The optical temporal differentiator is a fiber based polarization interferometer. The method provides a fast and simple recovery of the instantaneous frequency from two temporal intensity measurements, obtained by changing the spectral response of the interferometer. Pulses with different shapes and durations of hundreds of picoseconds are fully characterized in amplitude and phase. The technique is validated by comparing the measured pulse spectra with the reconstructed spectra obtained from the intensity and the recovered phase.

We propose a secure optical communication system based on the principles of generalized and complete synchronization of chaotic oscillations. Both a transmitter and a receiver are composed by two chaotic external-cavity semiconductor lasers which are coupled in a master-slave configuration to provide generalized synchronization, while the master lasers in the transmitter and in the receiver are completely synchronized via an optical fiber. A message is added to the slave laser in the transmitter and sent to the ...

Scanned-beam projection systems have attracted much interest recently, with claimed advantages including power efficiency and potential miniaturization consistent with embedding in
mobile devices. However, the laser-safety classification and concomitant performance implications,which are arguably the most important issues pertaining to this technology, remain widely misunderstood.

In this paper, Class 1 and 2 laser-safety radiometric image power limits for scanned-beam systemsare derived with reference to the IEC 60825-1 standard. By calculating the equivalent photometric measure of luminous flux, it is possible to show that the brightness limits for scanned beam projection systems using current technology are approximately 1 and 17 lm for Class 1 and 2safety classifications, respectively.

This paper deals with the simulation and implementation of boost Converter with the need for power factor correction, the utilization of active clamping technique in the boost converter, this circuit incorporation of compound active clamping boost converter, its modes of operation and analysis of step of chopper. This analysis involves the simulation analysis of the compound active clamping boost PFC converter. It gives the details about the circuit implementation. The laboratory model is implemented and the experimental results are obtained. These experimental results are correlated with the simulation results.

Haemangioma is the most common benign tumor of vascular origin of the head and neck region. This paper reports the management of a 39 year old female patient with capillary haemangioma on the ventral surface of the tongue and the floor of the mouth using 980 nm diode laser.