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Teeth bleaching with Epic diode laser

Teeth bleaching with Epic diode laser

Clinical case presentation. The clinical case presented refers to the teeth whitening protocol with hydrogen perox- ide gel activated with Epic Biolase diode laser light (940 nm). The anamnestic result did not show any indications of this type of treatment. The procedure was performed on the vestibular faces with teeth visible in the smile, respec- tively the frontal area up to the 1st molar at the jaw and the mandible. The postoperative sensitivity and the whitening performance of the work performed in a single session were analyzed.

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Design Coding Format For Optical Fiber Communications

Design Coding Format For Optical Fiber Communications

In principle, any light source could be used as an optical transmitter. In modern laser communication systems There are two type of optical light sources, such as Light emitting diode (LED) that give incoherent communication system. LED is a semiconductor device that emits incoherent light when an electric current passes through it. The light is low power and monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a device is known as an infrared emitting diode (IR). An LED or IR consists of the P-N junction, LED is based on the semiconductor diode. The light is generate by spontaneous emission process When the diode is forward biased. The I-P characteristics of the LED can be show in figure (2) [5]. Such as laser diode (LD) that give coherent communication system. Laser diode, also known as an injection laser, is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum. Laser diode similar to LED, it is formed from a p-n junction with forward biased and powered by injected electric current, where the optical power is created. As the current exceeds the threshold, the forward current and optical power are directly proportional [3].
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Oxygen dependent laser inactivation of murine norovirus using visible light lasers

Oxygen dependent laser inactivation of murine norovirus using visible light lasers

A schematic of the USPL set-up is shown in Fig. 1a. The Ti: Sapphire laser (Spectra-Physics Mai Tai, Santa Clara, CA) is pumped by a 10 W 532 nm Neodymium Vanadate laser which was frequency doubled from 1064 nm. The USPL generates 120-fs at a repetition rate of 76 MHz- and tunable wavelengths between 690 and 1060 nm. The light was frequency doubled (BBO crystal 6 × 6 × 0.7 mm, Altos Photonics, Inc., Bozeman, MT) to select wavelengths of 400, 408, 425, 450, and 465 nm. A 1-cm path length quartz cuvettes containing 1–2 ml of MNV sample were irradiated for various time durations (from zero to 4 h) and power levels (from 40 mW to 400 mW). A 15-cm lens focused the excitation light onto the sample resulting in pulse intensities in the range of 0.98 to 9.8 GW/cm 2 . A small spin bar (8 mm × 3 mm) and a magnetic stirrer were used to agitate the samples during treatment within the quartz cuvette. Experiments were also conducted using a 10 W 10 ps Neodymium Vanadate laser (Lumentum, 400 North McCarthy Blvd, Milpitas, CA) operating at a wave- length of 1064 nm with a repetiton rate of 76 MHz. The 10 ps laser was frequency doubled to 532 nm using a po- tassium titanyl phosphate (KTP) crystal prior to MNV treatments. The frequency-doubled laser produced 7 ps pulses at 532 nm and 1 W of average power. A 15-cm focal-length lens focused this light onto the sample result- ing in a pulse intensity of 0.26 GW/cm 2 . Continuous wave laser treatments of MNV were performed using a CW multi-mode diode laser at 408 nm wavelength (Lasever Inc., Ningbo, China). Depictions of the two different set-ups for the 408 nm CW laser are shown in Fig. 1b and c. A 15-cm focal-length lens focused the light onto the sample resulting in an average intensity of 39 KW/cm 2 . For 408CW defocused experiments CW (Fig. 1c), the beam was spread to approximately 12 mm diameter by a mirror and 2 inch diameter, 15-cm focal length N-BK7 plano-concave lens (Thorlabs Inc., Newton, NJ) on a 9-cm diameter petri dish containing 2 ml of MNV. The result- ing intensity in this experiment was 0.15 W/cm 2 . All experiments assayed were performed in triplicate (N = 3) and each dilution was assayed in triplicate (n = 9). All sample temperature increases were < 3 °C above room temperature during all treatments.
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Basic Laser Principles

Basic Laser Principles

Another procedure that can be used to make available potentially inexpensive, mass produced, low power, visible output DPSS lasers is mimicking semiconductor chip processing methods. In the late 1980s, MIT Lincoln Labs took this approach and created the “microchip” laser. A thin Nd:YVO 4 plate is polished flat and then diced into ~2-mm-square chips. Each of these chips is then optically contacted to similar, flat, diced KTP doubling crystal plates to make a cube. Prior to dicing, the surfaces that will become the outer cube surfaces are coated for high reflectivity at 1.06 mm. When single-mode diode laser pump light is focused through one mirrored end of the cube, the heat produced makes a thermally-induced waveguide that creates a stable cavity for IR las- ing. Since the KTP crystal is within this cavity, the IR lasing is con- verted to a 532-nm (green) output beam with 10’s of milliwats of output. The diode temperature must be controlled to maintain a sta- ble pump wavelength and thermal waveguide. In addition, the cube temperature should be stabilized. Because of the short cavity, the IR laser operates at a single longitudinal mode, and the cavity length must be thermally tuned to keep the mode at the peak of the gain curve. Laser operation in a single frequency suppresses “green noise,” discussed next.
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Thermal Analysis of Blue Laser Diode for Solid State Lighting Application

Thermal Analysis of Blue Laser Diode for Solid State Lighting Application

In past few years InGaN-based semiconductors have attracted much attention for application in solid-state light sources. Recently, their usage is constantly in- creasing in worldwide market. High-brightness white LEDs have been used due to their size, long life and energy saving. Also, white light can be generated from LEDs in three major ways: mixing blue, red and green diode [1] [2], coupling UV diode with RGB phosphor [3] or coupling blue diode with yellow phosphor [4]. The last method is the most convenient and efficient to generate white light How to cite this paper: Czesnakowska, A.,
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Determination of Planck’s Constant using Light Emitting Diodes

Determination of Planck’s Constant using Light Emitting Diodes

Light wavelength can be measured using a spec- trometer. Using the relationship, c = fλ, one can find the frequency emitted by any diode [4, 8, 9]. In this work, we start by considering the quan- tum mechanics of light absorption between two close states arbitrary taken as state 1 and state 2, with Eigen-functions with Eigen-values, ψ 1 , ψ 2

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The Laser Technology: New Trends in Biology and Medicine

The Laser Technology: New Trends in Biology and Medicine

LaserLight Amplified Stimulated Emission Radiation, unlike a standard light beam, is a source of monoch- romatic, coherent and unidirectional light. Lasers are installed widespread in everyday life across multiple nu- merous applications: CD and DVD, barcode scanners, entertainment, welding or cutting in industry, aid to fire control or alignment of roads and tunnels. In the medical field, lasers are diagnostic and therapeutic instruments that offer a whole range of solutions. The laser which enables for greater surgical precision is less invasive and promotes healing time or cure. This technique is generally much less traumatic than traditional surgical tech- niques. The first use of lasers in medicine was to damage the retina to understand ocular injury due to accidental exposure [1]. Since the first ruby laser, several devices have been improved placing ophthalmology at the fore- front of medical specialties using this technology. The laser has also many applications in the field of biology. Researchers take the technology to its limits by playing on two main parameters, the short laser pulses—to the femtosecond—, and energy beams. Since then, pulsed lasers have become increasingly popular for their ability to ablate biological tissue. For patient diagnosis and experimental studies, biological tissue can be either ana- lyzed under a microscope after immuno-histostaining or crushed for further molecular analysis. Laser-Assisted microdissection (LAM) provides a valuable link between these two approaches. It gives new insights into cellu- lar mechanisms, genetic disorders, tumor biomarker identification patient-tailored therapy. The development of light-absorbing nanoparticles that are nontoxic to biological tissue has provided further potential for a more tar- geted delivery of heat with minimal damage to healthy tissue. At an appropriate wavelength, exposure of a na- noparticle to a laser can trigger a photothermal effect in the particle whereby electronic oscillations at the par- ticle surface are converted to heat [2].
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Outcome of Micropulse Laser in Treatment of Open Angle Glaucoma in a Peripheral Hospital in Rivers State, Nigeria: Our Initial Experience

Outcome of Micropulse Laser in Treatment of Open Angle Glaucoma in a Peripheral Hospital in Rivers State, Nigeria: Our Initial Experience

The Micropulse Transscleral cyclophoto- coagulation provides consistent and predictable lowering of IOP with minimal ocular complications. In our study the mean IOP change over 6 months was 10.46mmHg (38.20%). There was no remarkable change in the visual acuity at 6 months post laser treatment and the median number of drugs needed by participants to achieve target IOP dropped from 3 to 1. It is a less invasive method of IOP control and is worth including in our armamentarium in treatment of glaucoma in Africa.

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Diode Laser Versus Scalpel Gingivectomy

Diode Laser Versus Scalpel Gingivectomy

Different methods can be used to remove tissue during gingivectomy and produce a good gingival margin, the most common is the conventional gingivectomy which is done by the use of scalpel, now a day’s Laser is widely spread and can be used to perform surgeries. Materials and methods: 50 patients divided into two equal groups, Group 1 gingivectomy was done by Diode Laser, Group 2 gingivectomy was done by scalpel, plaque and gingival index were measured at 1st, 2nd and 3rd visit, swab were taken and sent foe detecting bacterial growth and biopsy were taken for histopathological examination. Group 1 show no significant differences in plaque and gingival means between the visits, the bacteriological examination showed no growth of bacteria and histological examination revealed less inflammatory cells than Group 2. Group 2 show significant differences in plaque and gingival indices between the visits. Though scalpel remains the gold standard choice in gingivectomy but Diode laser may have some advantages over it.
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QAM Transmission over RoF Using Fabry Perot Laser Diode and Continuous Wave Laser Diode

QAM Transmission over RoF Using Fabry Perot Laser Diode and Continuous Wave Laser Diode

The performance analysis of the wireless transmission of OFDM over optical fiber connection is depicted in [4]. The transmission of OFDM over RoF connection can be utilized for short separation and long-run transmission with high information rate. The proposed framework can be helpful for Wireless LANs, Fiber-To-Home (FTH), WiMax, Digital Video Broadcasting (DVB) [4] and other low control advanced frameworks [5-10]. A Multi-Band Orthogonal Frequency Division Multiplexing (MBOFDM) transmission of utilizing Quadrature Phase Shift Keying (QPSK) adjustment for Ultra Wide Band (UWB) applications at 60-GHz RoF system is depicted in paper [11]. The transmission execution is assessed utilizing Error vector size (EVM) estimations. 60 GHz OFDM RoF framework dependent on optical recurrence duplication is exhibited in paper [12]. OFDM with staggered tweak configuration, for example, 16 QAM is depicted. More than 25 km fiber length immaterial power punishment is watched and framework can give more service range to broadened application. The simple transmission execution of single-mode Fabry-Perot Laser Diode (FPLD) is clarified in paper [13]. The proposed model depends on time area recreation of rate condition [13].In paper [14] a 60 GHz RoF Wavelength Division Multiplexing Passive Optical Networks (WDMPON) utilizing Parallel Phase Modulation with a Single MachZehnder Modulator (MZM) is displayed. The paper is additionally depicted distinction between Radio Frequency (RF) and base band adjustment in hypothetically just as tentatively. The optical millimeter age without bearer concealment for long separation fiber application is clarified in paper [15]. The decrease strategies for Inter-subcarrier Interference and Frequency-Selective Fading in OFDM RoF framework is exhibited in paper [15]. Turbo codes and bit interleaver innovations are proposed to dodge mistakes in OFDM RoF framework. In this paper, we proposed the performance of Quadrature Amplitude Modulation (QAM) Radio over Fiber (RoF) framework dependent on
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USE OF LASER IN TREATMENT OF PREMALIGNANT SKIN CONDITIONS

USE OF LASER IN TREATMENT OF PREMALIGNANT SKIN CONDITIONS

transformed into heat. As the local temperature is increased, different changes occur, and thermal effects appear on the skin. These effects are depe- nded not only on the temperature but also on the exposure time (Song, 2017). In fact, the absor- ption of laser lights in the tissue is the usual desi- rable effect and it is the beneficial aim for laser therapy. The absorbed energy depends on the wavelength of laser beam. In human body, there are several of light absorbers which are called chromophores (Azadgoli, 2016, Gandikota et al., 2017). Each one of them can absorb specific wav- elength as in Table 1. Furthermore, CO2 laser and Er: YAG laser have higher water absorption com- pared to other lasers. Because of that, most of the absorbed energy vanishes during the treatment due to the vaporization process. That is the reason why the treatments by those lasers have less heat transfer to surrounding area and deeper cells. That means, the therapy by laser does not have side effects and without long-standing implication on the skin as in figures 1B and 5B.
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DESIGNING OF LIGHT EMITTING DIODE

DESIGNING OF LIGHT EMITTING DIODE

Refrigerated display case lighting is a promising application for light emitting diodes as LEDs perform better in cold temperatures and do not produce radiated heat like conventional fluorescent technology. Lack of radiated heat loss the product shelf life and reduces losses of decaying goods. The cool light source saves additional energy as the refrigeration unit does not need to compensate for any heat generated by the light.

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Sampled grating DBR laser as a spectroscopic source in multigas detection at 1 52 1 57um

Sampled grating DBR laser as a spectroscopic source in multigas detection at 1 52 1 57um

Multigas detection has been achieved using a widely tunable SG-DBR laser diode as a light source using absorption spectroscopy.. The characteristics power, SMSR and wavelength tuning of [r]

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Vol 28, No 4 (2018)

Vol 28, No 4 (2018)

Between January 2015 and December 2015, eleven Libyan females patients aged between 32 years and 56 years (mean age 46.2 years) with 21 XP lesions were enrolled in the present study. Lesions ≥1cm over upper or lower eyelid were counted as a single lesion and those less than 1cm were not included. Blood sample after 12- hours fasting was analyzed for lipid profile from every patient. The laser procedure and the expected complications and the outcome were explained to every patient in a simple language prior to laser procedure. After informed consent, the lesions were cleaned with disinfecting solution then infiltrated with 1% lignocaine via insulin syringe attached to 29-G needle. Lesions were treated with one laser session with UCO2 laser (Fraxis from Ilooda; 10,600 nm; 100-200 Hz; 200-400 μs) with fixed spot-size handpiece (spot diameter 1.0 mm). The other eye was covered with opaque goggle and the photoablated eye was protected by aid of wooden tongue depressor held by an assistant. The photoablated tissue was gently removed with a cotton swap soaked in normal saline to expose the rest of underlying fatty tissue. Laser photoablation and gentle removal of photoablated tissue was repeated for 4-5 passes until the appearance of underlying pink tissue which was considered as the endpoint of laser photoablation. Post-operatively, patients were instructed to apply fusidic acid cream till crust formation and to keep the area clean and dry for the same duration. Photographic documentation of the lesion before laser treatment and immediately afterward and then reviewed at day
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The use of phototherapy in the treatment of diabetic ulcers

The use of phototherapy in the treatment of diabetic ulcers

Chronic ulcers are a common complication in diabetes. The nature of diabetic foot ulcers makes them difficult to manage and treat. A dynamic management plan is required to treat diabetic lower limb ulcerations. This involves a strategic approach, including mechanical offloading, wound debridement, wound dressing, patient education and surgical intervention. Alternative methods have been developed, of which phototherapy is one. Phototherapy, or low-level laser therapy (LLLT), is a therapeutic treatment modality that has been found to enhance wound healing. Its therapeutic properties have been determined by means of in vitro, in vivo and animal studies. Some studies have shown that the clinical application of phototherapy has a positive effect on the process of wound healing. Therefore, LLLT has the potential to decrease the level of secondary complications, improve wound regeneration, and ultimately improve patient quality of life. This review will discuss the concept of chronic wound management by means of LLLT in patients who suffer from type 2 diabetes.
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Indoor Channel Characteristics of Visible Light Communication

Indoor Channel Characteristics of Visible Light Communication

The Silicon p-type-Insulator-n-type Photodiode (Si PIN-PD) and Silicon Avalanche Photodiode (Si APD can be used as photodiodes because they have good responsively to visible light. There are several types of signal amplification circuits. The high impedance amplification is simple to implement. The series resistor is connected to the anode of the photodiode and the high input-impedance amplifier senses the voltage across the series resistor and amplifies it. The other one is trans-impedance amplifier that provides current-to-voltage conversion by using shunt feedback resistor around an inverting amplifier.
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Preparation of Cr-doped TiO2 thin film by sonochemical/CVD method and its visible light photocatalytic activity for degradation of paraoxon

Preparation of Cr-doped TiO2 thin film by sonochemical/CVD method and its visible light photocatalytic activity for degradation of paraoxon

spectroscopy) elemental analysis of the prepared samples were acquired by MIRA3 TESCAN field emission scanning electron microscope (Czech Republic). Photoluminescence (PL) emission spectra of the prepared samples were recorded using Cary Eclipse fluorescence spectrophotometer (Varian, Inc., USA) at room temperature, with an excitation wavelength of 320 nm. The UV–visible absorption spectra of the prepared thin films were obtained using Cary 100 Bio spectrophotometer (Varian, Inc., USA).

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The Effect of Light Emitting Diode Light on the Physical Traits of Chicks

The Effect of Light Emitting Diode Light on the Physical Traits of Chicks

Environmental conditions including light are considered a critical element of chicks well-being. The aim of the present study was to investigate the effect of LED light on the physical traits of chicks. We took forty-one-day-old chicks and randomly separated it into two groups. The chicks in the first group were reared under the effect of incandescent lamp light and in the second one were under the effect of white LED lighting. Chicks were daily monitored for indi- vidual chick body, weight gain, feed intake, feather color and fear responses. The distance between chicks and source of light was 50 cm. Student’s t-test test was used for statistical evaluation at p < 0.05 level. The results of the current study showed that chicks reared under incandescent light bulb had significantly higher body weight compared with chicks reared under LED light. The magni- tude of body weight in LED group was lower (1192.75 ± 149.9 g) compared to incandescent light group (1307.75 ± 110.5 g). The obtained results revealed that LED light reared chicks were more active; it showed long mobility duration and high levels of exploration in the farm as compared to those in incandescent light group. The results also indicated that incandescent light chicks were less fearful than LED chicks. Furthermore, the study showed that LED light reared chicks have pale pink combs and white feathers that cover all over the body. On the other hand, incandescent light reared chicks have dark red combs and whi- tish-yellow feathers that cover certain areas of the body especially chick wings, tail and head.
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Evaluation of Low-Level Laser Therapy with Diode Laser for the Enhancement of the Orthodontic Tooth Movement: a Split-Mouth Study

Evaluation of Low-Level Laser Therapy with Diode Laser for the Enhancement of the Orthodontic Tooth Movement: a Split-Mouth Study

Luger et al. [37] used doses of about 64 J/cm2 during 14 days, and although this dose could be excessive within the focused area, the authors believe that the scattering reduces the energy level of the laser beams to between 3 and 6% of its original intensity. In our study, the dose at each of the different points around the tooth was higher (66.7 J/cm2) than the dose used by Luger et al. (64 J/cm2), but the distribution of energy into six points surrounding the canine teeth could be more adequate due to a more homogeneous distribution of the energy.
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Temperature-dependent spectroscopy and microchip laser operation of Nd:KGd(WO4)2

Temperature-dependent spectroscopy and microchip laser operation of Nd:KGd(WO4)2

For the absorption measurements, undertaken with the 3 at.% sample, a broadband amplified spontaneous emission (ASE) source, a polarizer, and an optical spectrum analyzer (OSA) with 0.1 nm resolution were used. The experimental setup is shown in Fig. 1. Two different fiber-coupled (fiber diameter: 200 µm, N.A. = 0.22) light sources were employed. One of the sources was a diode laser with a nominal lasing wavelength of 805 nm (LIMO60-F200-DL808); however, operation below the laser threshold delivered ~100 mW of ASE covering the wavelength range 780-840 nm. The second source, an 870 nm high-power light-emitting diode (LED) (JET-870-05 Roithner Lasertechnik) produced ~10 mW of output power at the exit facet with an emission spectrum covering 850-910 nm. Both probe light sources were coupled into a measurement fiber. The exit facet of the latter was fixed in position and imaged in the sample with three times magnification. The light transmitted through the sample was subsequently re- imaged into the endface of a fiber patch cable and sent to an OSA (ANDO AQ6317B). A broadband cube polarizer was used to isolate the respective principal optical polarization of interest, || N m and || N p . Figure 2 illustrates emission spectra for both ASE sources measured
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