Application Of Diode Laser Research Articles

Effect of GaAs insertion layer on the properties improvement of InGaAs/AlGaAs multiple quantum wells grown by metal-organic chemical vapor deposition

Multiple quantum wells (MQWs) are commonly employed in InGaAs/AlGaAs semiconductor materials for devices such as semiconductor lasers and solar cells. However, the Indium atoms’ problems of segregation and large surface roughness, due to the different growth temperatures of well and barrier layers, have not yet been solved. In the present work, a GaAs material was designed as an insertion layer (ISL) and used in the structure of the InGaAs/AlGaAs MQWs. The study found that when the thickness of the GaAs ISL was 6 nm, the maximal properties of the InGaAs/AlGaAs MQWs were achieved. Various theoretical and experimental studies were performed to measure the crystal’s purity to elucidate the reasons for improving the InGaAs/AlGaAs MQWs. The measurements indicated that the AlGaAs barrier guaranteed more radiative recombination in the MQWs’ structure while simultaneously ensuring the GaAs ISL diminished surface roughness and the Indium atoms’ segregation. The design of the InGaAs/AlGaAs MQWs creates new opportunities for innovative applications of next-generation diode lasers with optimized integration.

Recent Advances of Near-Infrared (NIR) Emissive Metal Complexes Bridged by Ligands with N- and/or O-Donor Sites

Near-infrared (NIR) emissive metal complexes have shown potential applications in optical communication, chemosensors, bioimaging, and laser and organic light-emitting diodes (OLEDs) due to their structural tunability and luminescence stability. Among them, complexes with bridging ligands that exhibit unique emission behavior have attracted extensive interests in recent years. The target performance can be easily achieved by NIR light-emitting metal complexes with bridging ligands through molecular structure design. In this review, the luminescence mechanism and design strategies of NIR luminescent metal complexes with bridging ligands are described firstly, and then summarize the recent advance of NIR luminescent metal complexes with bridging ligands in the fields of electroluminescence and biosensing/bioimaging. Finally, the development trend of NIR luminescent metal complexes with bridging ligands are proposed, which shows an attractive prospect in the field of photophysical and photochemical materials.

STUDY OF THE EFFECT OF FLUORIDE ON LASER ENHANCED REMINERALIZATION OF DEMINERALIZED HUMAN ENAMEL

Background: Enamel is regularly subjected to demineralization and remineralization under different oral circumstances. Any interruption in the balance between demineralization and remineralization can initiate the formation of incipient caries lesions. However, in the early stage of formation these lesions can be remineralizedusing various preventive measures. Topical fluorides have shown positive results in the prevention of caries in several studies. The aim of this study was to determine the effects of combination between diode laser and topical fluoride application on the surface microhardness of the demineralized enamel. Materials and Methods: Four caries-free human premolars were examined under the stereomicroscope to exclude teeth with surface enamel defects. Buccal enamel surface microhardness (SMH) for all samples was measured by Micro Vickers Hardness Tester (MVHT). The samples were demineralized by 15% Hydrochloric acid (HCl) with PH average 4.5, then the SMH was measured. The demineralized teeth were subjected to fluoride toothpaste after diode laser application. Third evaluation for enamel SMH was performed after remineralization. Results: Enamel SMH of the control group has shown the highest values followed by the remineralization group while the least values were measured in the demineralization group. Conclusions: The results obtained in the study lead to the conclusion that application of fluoride toothpaste after diode laser could enhance the remineralization potential of the demineralized enamel.

A Study of Object Transparency Via Charge-Coupled Device Mathematical Modelling Assessment

This research discusses an application of Couple-Charge Device (CCD) linear sensor and laser diode in an optical tomography (OPT) system. Tomography is a system that could capture a cross-sectional image based on sensor data scattered across the periphery of the examining device in the non-invasive and non-intrusive framework. This project focuses on quantifying the level of object transparency based on CCD and mathematical modelling assessment. The objective of this project is to investigate the light refraction, reflection and absorption effect on object transparency. The study will include a discussion on the light parameters and its mathematical expression. The voltage output measured by CCD defines the degree of intensity of light obtained after penetrating through different object transparency. In conclusion, this research has successfully proved the potential of CCD in OPT configuration to detect different size diameters of a targeted transparent object, which is an air bubble in non-flowing crystal-clear liquid.

Improvement of cobalt-doped ZnS QD emission intensity and linewidth for future diode laser application

This research describes the preparation of Co-doped ZnS Quantum Dots (QDs) with a high-reactivity colloidal method. Homogeneous nucleation occurred at the precursors' high-reactivity temperature, which is found dependent on the dopant concentration. Two compositions were studied: Zn 0.095 SCo 0.005 and Zn 0.091 SCo 0.009 . The homogeneous nucleation occurred at 64 °C and 84 °C, respectively. Two schemes have been followed, temperature variation leading to an average QD size of 5.5 nm and aging routine, leading to a QD size of 5.0 nm. High-intensity emission spectral lines with a narrow linewidth that fell in the range of 1.4 nm–5 nm were observed. The purity of the created QD samples has been verified using elemental analysis. The X-ray diffraction (XRD) results of the crystal structure and high-resolution transmission electron microscopy (HRTEM) had shown coincidence. Doping ZnS QDs with cobalt reduced the FWHM from 3.67 nm to 1.40 nm. High emission intensities were observed at the most probable emission reported by the Co II's transition data. • Zn 0.1-x SCo x QDs were prepared by the high-reactivity temperature colloidal method. • Narrow linewidth high-intensity emission has been obtained. • The QDs sizes have been tuned during temperature and timing stages. • Quantum confinement occurred with all dopant concentrations. • Resonance absorption and emission energies were observed.

Comparative Evaluation of the Effects of Diode Laser and Desensitizing Agents on the Treatment of Dentin Hypersensitivity: a Clinical Study.

Background:Dentine hypersensitivity (DH) is a frequent clinical problem that represents a long-term painful discomfort for the patients, and for the dentists, it represents a diagnostic and therapeutic challenge.Objective:The aim of the research is to verify the effect of the treatment with diode laser SiroLaser Blue (660nm) of DH alone or in combination with different impregnating agents.Methods:Fifty patients were included in this research, separated into five groups. All the patients have been asked to define the level of dentine hypersensitivity using VAS (0-10). The first group was treated with Fluor Protector, the second group after the application of Fluor Protector has undergone irradiation with SiroLaser Blue (660nm), the third group was treated with impregnating agent Vivasens, the fourth group, after the application of impregnating agent Vivasens, has had SiroLaser Blue (660nm) irradiation. The fifth group has just been treated with SiroLaser Blue (660nm). The efficiency of the treatment was checked using VAS for every group immediately after the conducted treatment, after 7 days and 1 month.Results:Our results showed that all of the desensitizing agents used in the research alone or in combination with a diode laser (660nm) have shown a reduction of DH. The difference has been proven statistically significant in mean values by groups and examinations. Vivasens and diode laser irradiation have provided the best results in the review of mean values after the first examination and one month after the treatment of DH (p<0,05). In our research, the application of diode laser alone has not proven superior to other treatment methods that have been used in the research.Conclusion:Vivasens plus diode laser irradiation has provided the best results even after one month since the treatment of DH.

Comparative evaluation of the efficacy of diode laser as an adjunct to modified Widman flap surgery for the treatment of chronic periodontitis: A randomized split-mouth clinical trial.

Background:Periodontitis is a chronic inflammatory disease that is mainly initiated by plaque biofilm which may require treatment using periodontal flap surgery. Recently, diode lasers have become popular in the field of periodontology owing to advantages such as antibacterial effect, promoting angiogenesis, and providing hemostasis. However, scientific data on application of diode laser in periodontal flap surgery and its benefits are limited. Hence, the aim of the study was to investigate the adjunctive effect of removal of remnant pocket epithelium by 980 nm diode laser and biostimulation in modified Widman flap (MWF) surgery for the treatment of chronic periodontitis.Materials and Methods:A total of 20 patients with generalized chronic periodontitis with pocket probing depth (PPD) ≥5mm post Phase I therapy were selected for this split-mouth study. MWF surgery was performed in Group 1, and in Group 2, MWF surgery with adjunctive diode laser de-epithelization and biostimulation was done. Clinical parameters including PPD, clinical attachment level, plaque index, and gingival index were recorded at baseline and 3 months following treatment, and postprocedural pain (Visual Analog Scale [VAS] score) was assessed 1-week posttreatment. In addition, colony-forming units/milliliter (CFU/ml) of anaerobic bacteria at baseline and 3 months were microbiologically examined.Results:MWF surgery along with diode laser led to a significant improvement in Group 2 compared to Group 1 in clinical parameters such as PPD, relative clinical attachment level, VAS score as well as microbial parameter CFU/ml after 3 months.Conclusion:Diode laser as an adjunct to MWF in chronic periodontitis can provide enhanced clinical attachment gain with little postoperative discomfort.

Immediate effects of diode laser (970±15 nm) on microbial load in patients with chronic periodontitis: A split-mouth study.

Periodontitis is a multifactorial disease, and the causative periodontal pathogens have been detected in patient samples like plaque, gingival crevicular fluid (GCF), saliva, crevicular blood, gingival tissues, etc. Laser disinfection is an advanced treatment that has been shown to alter the bacterial flora and have greater efficacy in reducing the progression of the disease. This study is aimed to evaluate the immediate effects of a diode laser (970 ± 15 nm) on the microbial load in GCF, crevicular blood, and saliva samples of patients suffering from chronic periodontitis. A total of 45 subjects were recruited for the study. Each patient's mouth was divided equally into two halves, which were allotted randomly into two groups. In group I (test group), diode laser disinfection was performed, and in group II (control group), saline irrigation was performed. The GCF, saliva, and crevicular blood samples were collected before and immediately after disinfection for microbial analysis. Clinical observations showed a reduction in microbial load in both groups, which were statistically significant in the test group. GCF and saliva samples showed greater reduction when compared with crevicular blood samples in both groups. This study concludes that the application of diode laser (970 ± 15 nm) has immediate reducing effects on the microbial load in GCF, crevicular blood, and saliva samples in patients with chronic periodontitis.

Clinical Applications of Diode Laser

Clinical Applications of Diode Laser

A Study of Object Transparency Via Charge-Coupled Device Mathematical Modelling Assessment

This research discusses an application of Couple-Charge Device (CCD) linear sensor and laser diode in an optical tomography (OPT) system. Tomography is a system that could capture a cross-sectional image based on sensor data scattered across the periphery of the examining device in the non-invasive and non-intrusive framework. This project focuses on quantifying the level of object transparency based on CCD and mathematical modelling assessment. The objective of this project is to investigate the light refraction, reflection and absorption effect on object transparency. The study will include a discussion on the light parameters and its mathematical expression. The voltage output measured by CCD defines the degree of intensity of light obtained after penetrating through different object transparency. In conclusion, this research has successfully proved the potential of CCD in OPT configuration to detect different size diameters of a targeted transparent object, which is an air bubble in non-flowing crystal-clear liquid.

Single-Crystal Red Phosphors and Their Core-Shell Structure for Improved Water-Resistance for Laser Diodes Applications.

A solvent-vapor transport route produces centimeter-sized single-crystal red phosphors. The epitaxial growth route to yield its core-shell structure at ambient temperature was adopted. These red phosphors could be applied in all-inorganic WLED devices. Cs2 TiF6 :Mn4+ (CTFM) single crystal provides enhancement of quantum efficiency, moisture resistance, and thermal stability compared to polycrystalline powders. The internal quantum efficiency can reach as high as 98.7 %. To further improve waterproof stability, the Cs2 TiF6 (CTF) shell with tunable thickness has been epitaxially grown on the CTFM single crystal surface and a unique three-step photoluminescence intensity evolution mechanism has been proposed. By combining as-prepared CTFM@CTF core-shell structured single crystal, YAG:Ce single crystal and blue-chip, warm WLEDs with excellent color rendition (Ra =90, R9 =94), low correlated color temperature (CCT=3155 K), and high luminous efficacy were fabricated without any organic resins.

Single‐Crystal Red Phosphors and Their Core–Shell Structure for Improved Water‐Resistance for Laser Diodes Applications

AbstractA solvent‐vapor transport route produces centimeter‐sized single‐crystal red phosphors. The epitaxial growth route to yield its core–shell structure at ambient temperature was adopted. These red phosphors could be applied in all‐inorganic WLED devices. Cs2TiF6:Mn4+ (CTFM) single crystal provides enhancement of quantum efficiency, moisture resistance, and thermal stability compared to polycrystalline powders. The internal quantum efficiency can reach as high as 98.7 %. To further improve waterproof stability, the Cs2TiF6 (CTF) shell with tunable thickness has been epitaxially grown on the CTFM single crystal surface and a unique three‐step photoluminescence intensity evolution mechanism has been proposed. By combining as‐prepared CTFM@CTF core–shell structured single crystal, YAG:Ce single crystal and blue‐chip, warm WLEDs with excellent color rendition (Ra=90, R9=94), low correlated color temperature (CCT=3155 K), and high luminous efficacy were fabricated without any organic resins.

Modeling and Epitaxial Growth of Homogeneous Long-InGaN Nanowire Structures.

One-dimensional nanowires based on Group III-nitride materials are emerging as one of the most promising structures for applications of light-emitting diodes (LEDs), laser diodes (LDs), solar cells, and photocatalysts. However, leading to the so-called “green gap” in photonics, the fabrication of high concentration indium gallium nitride (InGaN) and long-InGaN structures remains still challenging. In this study, we performed simulations for structural modeling of uniform temperature distribution in a nanowire epitaxy, and have successfully developed high-concentration InGaN and long-InGaN nanowire heterostructures on silicon (Si) substrate using molecular beam epitaxy (MBE) system. From scanning electron microscope (SEM) and transmission electron microscope (TEM) results, it was confirmed that the various doped-InGaN nanowire structures show much higher crystal quality compared to conventional nanowire structures. By introducing a new three-step modulated growth technique, the n-/p-InGaN active regions were greatly increased and the optical properties were also dramatically improved due to reduced phase separation. In addition, a multi-band p-InGaN/GaN heterostructure was successfully fabricated with the core–shell nanowire structures, which enable the emission of light in the entire visible spectral range, and protect the InGaN surface from surface recombination. This paper offers important insight into the design and epitaxial growth of InGaN nanowire heterostructures.

Application of a Medical Diode Laser (810 nm) for Disinfecting Small Microbiologically Contaminated Spots on Degraded Collagenous Materials for Improved Biosafety in Objects of Exceptional Historical Value From the Auschwitz-Birkenau State Museum and Protection of Human Health.

The research aim was to optimize the operating parameters of a diode laser irradiation for the effective disinfection of degraded collagenous materials. Historical leather shoes stored at the Auschwitz-Birkenau State Museum in Oświęcim (Poland) were the main study objects. Surfaces of contaminated small spots occurring on the degraded materials were sampled with moistened swabs and microbiologically examined using the molecular techniques MALDI-TOF MS, 16S rRNA, and NGS sequencing. The surfaces were colonized by bacteria with 106 CFU/100 cm2 and 104 CFU/100 cm2 by fungi, on average. Microorganisms of the genera Bacillus and Penicillium were predominant. The effectiveness of the laser treatment was assessed for the new and degraded collagenous materials against isolated environmental strains using four variants of exposure time and number of repetitions. 0.3 W/CW 2 × 2 min variant was the most effective and also did not noticeably change the color of the treated samples. The variant caused a reduction in the numbers of microorganisms by 96–100%. After 1 month, four types of leather were subjected to comprehensive physico-chemical analyses. SEM and FTIR techniques confirmed that laser irradiation in the selected optimal variant did not affect the surface morphology and collagen structure, while XPS technique enabled detection of subtle changes in non-historical protective coatings on the surfaces of tested degraded historical materials.

In vivo investigation of diode laser application on red complex bacteria in non-surgical periodontal therapy: a split-mouth randomised control trial

Assessment of the efficacy of a single 810 nm diode laser application as an adjunctive treatment modality during the first intervention of non-surgical periodontal therapy (NPT). 25 patients diagnosed with chronic periodontitis underwent a split-mouth randomised control trial. The periodontal pockets of the test quadrants were treated with an 810 nm diode laser as an adjunct to NPT (Picasso GaAlAs; AMD Lasers). The laser was set at 1.0 W continuous wave, 400 µm tip, 796 W/cm2 peak power density and a 32 J/cm2 energy density. Therapeutic outcomes were evaluated based on the clinical parameters, which included probing pocket depth, recession, clinical attachment level, full mouth plaque score, full mouth bleeding on probing and tooth mobility. The baseline bacterial collection was completed from the periodontal pockets and then re-evaluated at 6 weeks. Clinical parameters demonstrated no statistical difference, with the exception of a statistically significant (P < 0.05) reduction in bleeding on probing for the test side. The test side resulted in a statistical increase of Capnocytophagaspecies and Treponemadenticola. The single application of the diode laser did not significantly improve the bacterial nor the clinical parameters in patients with chronic periodontitis.Trial registration number: PACTR201909915338276.

Streptococcus Mutans Biofilm Inhibition Effect of Indocyanine Green and Near Infrared Diode Laser

The purpose of this study was to evaluate the effect of Indocyanine Green (ICG) and near-infrared (NIR) diode laser on &lt;i&gt;Streptococcus mutans&lt;/i&gt; biofilms depending on ICG concentrations.&lt;br/&gt;&lt;i&gt;S. mutans&lt;/i&gt; biofilms were formed on a Hydroxyapatite disk, and 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 mg/mL ICG solutions dissolved in sterile distilled water and a NIR diode laser having a power of 300 mW and a wavelength of 808 nm were applied to the biofilms. The temperature changes of the biofilm surface according to the concentrations of the ICG solution were measured using a 1-channel thermocouple thermometer.&lt;br/&gt;Compared to the control group, in the groups with only the 3.0, 4.0, 5.0 mg/mL ICG solution application, and in the groups with the 1.0, 2.0, 3.0, 4.0, 5.0 mg/mL ICG solution application and light irradiation, a statistically significant decrease in the bacterial counts were observed.&lt;br/&gt;The temperature increase according to the concentration of the ICG solutions was 9.53℃, 10.43℃, 11.40℃, 12.10℃, 12.67℃, and 13.63℃ in ICG solutions of 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 mg/mL respectively.This study presents the potential for clinical application of ICG and NIR diode lasers as a new method for preventing dental caries.

SURG-43. APPLICATIONS AND RESTRICTION OF 980NM DIODE LASER FOR BRAIN TUMOR MICROSURGERY - A PIONEER CASE SERIES AND A CRITICAL REVIEW

Abstract BACKGROUND Quality of life is essential for oncological patients. There are several tools that help surgery become more precise with less morbidity. Diode laser can cut and coagulate through thermal effect being helpful during surgery. It is a precise and useful technology that improves outcomes in neurooncology. OBJECTIVES To describe a pioneer case series of oncological use of diode laser and main applications of several types of laser in neurooncology. METHODS Detailed description of a pioneer case series of oncological patients that undergone to neurosurgical laser assisted procedures. An interventional longitudinal prospective study was conducted. Patients that had as mainly hypothesis the diagnosis of glioma or meningioma were selected. Also it was performed an extensive literature review about lasers in neurosurgery with special focus in diode laser. RESULTS There was not any paper describing the use of diode laser in neurooncology. The 980nm diode laser was used in 15 patients. The device had an easy handling. Decreased intra-operative time for hemostasis, lesser blood loss requiring less blood transfusion was observed. No post-operative complications occurred. CONCLUSIONS Diode laser is a useful tool for brain tumor surgery especially concerning hemostasis, providing decreased blood loss with lesser intra-operative duration. Surgical site coagulation is more effective causing less damage to adjacent structures specially in gliomas near eloquent regions. We consider this technique as a suitable adjuvant therapy for brain tumor surgeries providing an excellent hemostasis and helping cutting and vaporize lesion. This device makes surgery safer and decrease oncological morbidity.

The photonic and luminescence characteristics of the lasing NdxGa1-xAs quantum dots prepared via N-diphenyl-N-bis3-methylphenyl-1-biphenyl-4-diamine assisted colloidal approach

Here, we report the photonic and luminescence characteristics of the lasing NdxGa1-xAs quantum dots prepared via N-diphenyl-N-bis3-methylphenyl-1-biphenyl-4-diamine assisted colloidal approach for laser diode potential application. The prepared NdxGa1-xAs quantum dots showed cubic crystal structure as evidenced from XRD. The optical behavior showed a redshift of the absorbance and emission spectra, and a decrease of the optical bandgap from 2.4 eV to 1.82 eV. The Nd-atomic dopant raised the emission spectral intensity and reduced the bandwidth of the emitted light. The Nd-dopants suppress the surface defects of the GaAs nanocrystals and creates populating levels within the GaAs bandgap. The NdxGa1-xAs quantum dots exhibited quantum yield of 91 %. Therefore, the NdxGa1-xAs nanocrystal quantum dots most probably employed as efficient lasing materials for optical amplifier and laser diodes applications.

The luminescence and quantum optical efficiency characteristics of Lu-doped CdSe QDs prepared by ethylglycol assisted solvothermal approach for laser diode and multicolor display window applications

A highly crystalline Cd 1-x Lu x Se semiconducting quantum dots were concocted using ethylglycol assisted solvothermal route. The XRD revealed that the Cd 1-x Lu x Se QDs exhibiting a zinc blende cubic structure. The TEM measurement disclosed that the Cd 1-x Lu x Se nanocrystals have nanoparticle like sphere with average sizes in the range of 2.7 nm to 9.1 nm as the amount of Lu-dopant incorporated in CdSe was increased. The absorbance spectrum confirmed that the Lu-dopant establish sublevels inside the CdSe bandgap, which prompted a decrease of bandgap from 3.1 eV to 2.75 eV. An enhancement of the emission spectra intensities and reduction of the spectral bandwidth was successfully achieved. The Lu-dopant enhanced the quantum yield from 18 % to 81 %. The intensive and sharp luminescent emission light emerged from the Cd 1-x Lu x Se QDs with quantum efficiency of 81 %, pave the way for a novel family of QDs capable to be employed for laser diodes and multicolor display windows.

Study on the proximity of QWI in InP-based AlGaInAs MQWs using the IFVD method and its application in single frequency teardrop laser diodes.

This paper presents our research on quantum well intermixing (QWI) of InP-based AlGaInAs/AlGaInAs multi-quantum wells using impurity-free vacancy-disordering (IFVD) and the QWI mask proximity effect and its application in the design and fabrication of a teardrop laser. Using a Si3N4 film deposited by plasma-enhanced chemical vapor deposition (PECVD) as a QWI promoter mask and annealing under 700°C for 2 minutes, a 70 nm wavelength blue shift of a FP laser is achieved using InP-based AlGaInAs quantum well laser material. It is found that a 5 µm separation is needed between the QWI mask edges and the non-QWI area during the QWI process. Based on the QWI technique and proximity effect, the designed and fabricated teardrop laser demonstrated continuous wave (CW) lasing above 40 mA and single frequency operation with a side mode suppression ratio of 32.6 dB at 77.3 mA.