Application Of Laser Technology Research Articles

Estimation of Articular Cartilage Surface Roughness Using Gray-Level Co-Occurrence Matrix of Laser Speckle Image.

The application of He-Ne laser technologies for description of articular cartilage degeneration, one of the most common diseases worldwide, is an innovative usage of these technologies used primarily in material engineering. Plain radiography and magnetic resonance imaging are insufficient to allow the early assessment of the disease. As surface roughness of articular cartilage is an important indicator of articular cartilage degeneration progress, a safe and noncontact technique based on laser speckle image to estimate the surface roughness is provided. This speckle image from the articular cartilage surface, when illuminated by laser beam, gives very important information about the physical properties of the surface. An experimental setup using a low power He-Ne laser and a high-resolution digital camera was implemented to obtain speckle images of ten bovine articular cartilage specimens prepared for different average roughness values. Texture analysis method based on gray-level co-occurrence matrix (GLCM) analyzed on the captured speckle images is used to characterize the surface roughness of the specimens depending on the computation of Haralick’s texture features. In conclusion, this promising method can accurately estimate the surface roughness of articular cartilage even for early signs of degeneration. The method is effective for estimation of average surface roughness values ranging from 0.09 µm to 2.51 µm with an accuracy of 0.03 µm.

Management of vascular lesions using advanced laser technology

<p>One of the most widely used cutaneous applications of Light Amplification by Stimulated Emission of Radiation (laser) concerns the treatment of vascular lesions. During the past two decades, very significant advances in the application of laser technology in dermatology have occurred, with selective photothermolysis being the most important. This review focuses on the application of modern laser devices (Pulsed Dye Laser, or PDL; potassium titanyl phosphate laser, or KTP; diode laser; and neodymium-doped yttrium-aluminium-garnet laser, or Nd:YAG), as well as the combination of laser and photodynamic therapy (PDT) for the treatment of vascular lesions. In particular, both congenital (haemangiomas and port-wine stains) and acquired vascular lesions (facial and leg telangiectasias, rosacea, Poikiloderma of Civatte, spider angioma, pyogenic granuloma, and venous lakes) are discussed. The review of many recent research studies demonstrates that modern applications of lasers in dermatology constitute the finest method for the treatment of vascular lesions, combining the advantages of invasive therapy with the security offered by non-invasive therapy, while in certain cases they are the single and only choice for the treatment of these lesions.</p>

Wetting properties of Nd:YAG laser treated copper by SAC solders

PurposeThis paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are increasing constantly. A specific laser treatment can modify the surface energy of copper and affect the wetting properties.Design/methodology/approachThe surfaces of copper plates were treated using an Nd:YAG laser with varying laser powers. After laser surface treatment, wetting experiments were performed between the copper plates and SAC305 lead-free solder paste. The effect of laser treatment on copper surface was analysed using optical microscopy and scanning electron microscopy (SEM).FindingsThe experimental results showed that the wetting contact angles changed with the variation in laser power. Furthermore, it means that the surface energy of copper plates was changed by the laser treatment. The results demonstrated that the contact angles also changed when a different soldering paste was used.Originality/valuePrevious laser surface treatment can be a possible way to optimize the wettability between solders and substrates and to increase the quality of the soldered joints.

Control of terahertz nonlinear transmission with electrically gated graphene metadevices

Graphene, which is a two-dimensional crystal of carbon atoms arranged in a hexagonal lattice, has attracted a great amount of attention due to its outstanding mechanical, thermal and electronic properties. Moreover, graphene shows an exceptionally strong tunable light-matter interaction that depends on the Fermi level - a function of chemical doping and external gate voltage - and the electromagnetic resonance provided by intentionally engineered structures. In the optical regime, the nonlinearities of graphene originated from the Pauli blocking have already been exploited for mode-locking device applications in ultrafast laser technology, whereas nonlinearities in the terahertz regime, which arise from a reduction in conductivity due to carrier heating, have only recently been confirmed experimentally. Here, we investigated two key factors for controlling nonlinear interactions of graphene with an intense terahertz field. The induced transparencies of graphene can be controlled effectively by engineering meta-atoms and/or changing the number of charge carriers through electrical gating. Additionally, nonlinear phase changes of the transmitted terahertz field can be observed by introducing the resonances of the meta-atoms.

Achieving Aesthetic Results by Using Laser in Minimally Invasive Dentistry Approach

The preservation of healthy human body and function for every patient should be the goal of all health practitioners. Dentistry is not an exception to this philosophy. In past few decades, the improvements of scientific method and technology has led to a better understanding of oral microflora and dental materials resulted in the shifting of caries management method from G. V. Black’s “extension for prevention” to the modern “minimally invasive” approach in dentistry. The minimally invasive approach to dental caries establishes a proper doctor-patient relationship, thus empowering and educating the patient to take responsibility for their own dental health. The proper sequence of caries management should be the introduction of preventive strategies such as oral hygiene instructions, reminialization regiments, and risk assessments followed by minimal surgical interventions. Using the laser technology in the aspect of surgical intervention has many clinical advantages. Some of the clinical benefits include its selectivity for carious tissue, reduction of needs for local anesthesia, decontamination effect of preparation surfaces, minimal thermal stimulus to pulp chamber, increase in surface adhesion for composite materials, and other soft tissue applications. The combination of caries prevention program, disease control, risk assessment, and laser technology application on the surgical intervention significantly reduces the long-term restorative needs and thus preserves more healthy natural tooth structures, which complement the concept of minimally invasive dentistry. In cosmetic surgery, the same rules apply. The same laser types are used as well.

Spatiotemporal distributions of plasma and optical field during the interaction between ultra-short laser pulses and water nanodroplets

The transient changes of free electron density distribution and light field intensity during the interaction between the femtosecond Gaussian laser pulses and millimeter scale water droplets are studied. Based on the nonlinear Maxwell's equations and the ionization rate equation, a transient coupled model is proposed to describe the laser plasma produced in water droplet. The changes of electron density and light field with time are obtained by the finite element method. The calculation results show that the laser induced breakdown threshold in the droplet is about 2 TW/cm2, one quarter of that in a boundaryless water medium under the same condition. We find that the region of plasma generated in the droplet will move along the laser direction at first, however, when the incident laser intensity becomes larger, it will move in the direction opposite to the laser beam propagation and the plasma shielded effect becomes more obvious. The laser beam converged by the droplet focuses outside the droplet, and its power density is five times larger than that of the incident laser. There happen the laser pulse duration compression and waveform distortion at the focus point due to the plasma absorption, and the absorption energy increases with the laser intensity increasing and reaches a saturation finally. We expect the model and calculation results to be able to be used for the study of laser pulse propagation in cloud or rain, the precision control of droplet by laser or eye surgery by laser, and other laser technology applications.

Laser application in neurosurgery.

Background:Technological innovations based on light amplification created by stimulated emission of radiation (LASER) have been used extensively in the field of neurosurgery.Methods:We reviewed the medical literature to identify current laser-based technological applications for surgical, diagnostic, and therapeutic uses in neurosurgery.Results:Surgical applications of laser technology reported in the literature include percutaneous laser ablation of brain tissue, the use of surgical lasers in open and endoscopic cranial surgeries, laser-assisted microanastomosis, and photodynamic therapy for brain tumors. Laser systems are also used for intervertebral disk degeneration treatment, therapeutic applications of laser energy for transcranial laser therapy and nerve regeneration, and novel diagnostic laser-based technologies (e.g., laser scanning endomicroscopy and Raman spectroscopy) that are used for interrogation of pathological tissue.Conclusion:Despite controversy over the use of lasers for treatment, the surgical application of lasers for minimally invasive procedures shows promising results and merits further investigation. Laser-based microscopy imaging devices have been developed and miniaturized to be used intraoperatively for rapid pathological diagnosis. The multitude of ways that lasers are used in neurosurgery and in related neuroclinical situations is a testament to the technological advancements and practicality of laser science.

Widely tunable lasing with lowered threshold in a two-dimensional indium-tin-oxide distributed-feedback structure

We demonstrated widely tunable lasing with lowered threshold in a liquid crystal (LC) laser by introducing a nanostructured indium-tin-oxide (ITO) film with two dimensional (2D) periodicity and two kinds of organic dyes in the nematic LC host. From a wedge-shaped distributed feedback (DFB) resonator, thickness of a LC layer and effective refractive indices of guided laser modes are modulated by changing the pumping position spatially, and the lasing emission is tuned by 26 nm. This LC DFB laser with wide spectral tunability and low threshold provides various approaches for practical applications in laser technology.

The application of lasers in otorhinolaryngology

The objective of this review is to summarize and systematize the data concerning the modern laser and laser-based systems, their characteristics, and possible applications in various spheres of medicine including otorhinolaryngology. The application of laser technologies in medical practice gains ever increasing popularity. Lasers have been successfully used during a long period for the diagnostic and therapeutic purposes. At present, they are just as actively applied in different fields of the surgical practice. Otorhinolaryngology makes the most extensive use of neodymium, CO2, and holmium lasers. The latter has the most universal characteristics and is operated in a relatively short wavelength range (λ=2.01 mcm); moreover, its radiation penetrates as deep as 0.4 mm into the biological tissues. In other words, the holmium laser not only combines the advantages of the CO2 and neodymium lasers but is also devoid of their shortcomings. The holmium laser is considered to be the most promising source of laser radiation for the application in otorhinolaryngological surgery with a potential encompassing the most wide spectrum of surgical manipulations needed to treat pathological changes in the ears, nose, and throat. The application of this instrument in medical practice opens up new prospects for the development of otorhinolaryngology.

Minimally Invasive Dentistry Approach Benefits of Using Laser

The preservation of healthy human body and function for every patient should be the goal of all health practitioners. Dentistry is not an exception to this philosophy. The loss of human tooth structure should be regarded as a serious injury and never to be considered lightly, therefore it is imperative to provide the most comprehensive and conservative care to all teeth. In past few decades, the improvements of scientific method and technology has led to a better understanding of oral micro flora and dental materials resulted in the shifting of caries management method from G.V. Black’s “Extension for prevention” to the modern “Minimally invasive” approach in dentistry. The minimally invasive approach to dental caries encompasses the science of detection, diagnosis and treatment on the microscopic level. The approach also establishes a proper doctor-patient relationship thus empowering and educating the patient to take responsibility for their own dental health. It has been widely accepted that the restorative materials and preparation designs are not the cure for caries. The dentist must recognize that the caries is a bacterial disease and the elimination of disease should be the priority before initiating any restorations. The proper sequence of caries management should be the introduction of preventive strategies such as oral hygiene instructions, remineralisation regiments, and risk assessments followed by minimal surgical interventions. Using the laser technology in the aspect of surgical intervention has many clinical advantages. Some of the clinical benefits include its selectivity for carious tissue, reduction of needs for local anaesthesia, decontamination effect of preparation surfaces, minimal thermal stimulus to pulp chamber, increase surface adhesion for composite materials, and other soft tissue applications. A critical evaluation of disadvantages on laser should also be considered when implementing its use in the clinical practice. The combination of caries prevention program, disease control, risk assessment and laser technology application on the surgical intervention significantly reduce the long term restorative needs thus preserve more healthy natural tooth structures, which complimenting the concept of minimally invasive dentistry. This presentation summarized various articles within the past 15 years regarding to topics of minimal invasive dentistry and laser technology usage in dentistry.

Femtosecond Laser-Assisted LASIK Flap Complications.

To discuss intraoperative and postoperative femtosecond laser-assisted LASIK flap complications and their management. Review of published literature. Flap creation is a critical step in LASIK. The femtosecond laser has improved the overall predictability and safety of the lamellar incision, but complications can still occur during or after flap creation. Although many complications (eg, epithelial ingrowth and flap striae) were reduced with the femtosecond laser application, other specific complications have emerged, such as vertical gas breakthrough, opaque bubble layer, and transient light-sensitivity syndrome. The application of femtosecond laser technology to LASIK flap creation has increased greatly since its introduction. These lasers have improved the safety and predictability of the lamellar incision step. The majority of the femtosecond laser-assisted flap complications can be well managed without significant effects on refractive outcomes.

Precise Transurethral Enucleation of Prostate: New Surgery Treatment for Benign Prostate Hyperplasia

There have been many advances in the surgical treatment for benign prostate hyperplasia (BPH), moving from open surgery (retropubic and suprapubic open prostatectomy) to transurethral resection of the prostate (TURP, the historical gold standard and still the most commonly used approach), and onto endoscopic transurethral enucleation. The application of new laser and plasma technologies now allows the precise transurethral enucleation of the prostate (PTUEP). In our medical center, we have found great success using PTUEP. Many urologists have found that PTUEP reduces perioperative complications and risks during operation. It can be applied to all size prostates and can even be used with BPH patients taking anticoagulation medicine. PTUEP is quickly replacing TURP as an effective and less invasive approach to BPH surgery.

New Possibilities in the Fabrication of Hybrid Components with Big Dimensions by Means of Selective Laser Melting (SLM)

The application of laser technology to welding of dissimilar AISI316 stainless steel components manufactured with selective laser melting (SLM) and traditional methods has been investigated. The role of laser parameters on weld bead formation has been studied experimentally, with particular attention placed on effects occurring at the interface between the two parts. In order to assess weld bead characteristics, standardised tensile tests were carried out on suitable specimens and the fracture zone was analysed. The results highlighted the possibility of exploiting suitable process parameters to appropriately shape the heat affected and fusion zones in order to maximise the mechanical performance of the component and minimise interactions between the two parent metals in the weld bead.

Femtosecond Laser Assisted Cataract Surgery in White Cataract

Aim: To demonstrate application of femtosecond laser technology in patients with white cataract. Methods: Video-based description of successful management of intumescent white cataract with femtosecond laser technology. Results: We performed femtosecond laser assisted cataract surgery in multiple patients with different morphologies of white cataract. Successful completion of capsulotomy along with intraocular lens implantation in the bag was achieved in all the cases. No case had extension of capsulotomy upto the periphery. Conclusion: Femtosecond laser technology has revolutionized the management of difficult cataract case scenarios especially intumescent white cataract. Intraocular lens implantation in the bag with ideal capsular margin overlap can be achieved with ease in most cases.

A Preliminary Report on the CO2 Laser for Lumbar Fusion: Safety, Efficacy and Technical Considerations.

The purpose of this study was to evaluate potential technical advantages of the CO2 laser technology in mini-open transforaminal lumbar interbody fusion (TLIF) surgeries and report our preliminary clinical data on the safety and clinical outcomes. There is currently no literature discussing the recently redeveloped CO2 laser technology application for lumbar fusion. Safety and clinical outcomes were compared between two groups: 24 patients that underwent CO2 laser-assisted one-level TLIF surgeries and 30 patients that underwent standard one-level TLIF surgeries without the laser.There were no neural thermal injuries or other intraoperative laser-related complications encountered in this cohort of patients. At a mean follow-up of 17.4 months, significantly reduced lower back pain scores (P=0.013) were reported in the laser-assisted patient group compared to a standard fusion patient group. Lower extremity radicular pain intensity scores were similar in both groups. Laser-assisted TLIF surgeries showed a tendency (P = 0.07) of shorter operative times that was not statistically significant.Based on this preliminary clinical report, the safety of the CO2 laser device for lumbar fusion surgeries was assessed. There were no neural thermal injuries or other intraoperative laser-related complications encountered in this cohort of patients. Further investigation of CO2 laser-assisted lumbar fusion procedures is warranted in order to evaluate its effect on clinical outcomes.

Innovation Study for Laser Cutting of Complex Geometries with Paper Materials

Even though technology for laser cutting of paper materials has existed for over 30 years, it seems that results of applications of this technology and possibilities of laser cutting systems are not easily available. The aim of this study was to analyze the feasibility of the complex geometry laser cutting of paper materials and to analyze the innovation challenges and potential of current laser cutting technologies offer.This research studied the potential and possible challenges in applying CO2 laser cutting technology for cutting of paper materials in current supply chains trying to fulfil the changing needs of customer in respect of shape, fast response during rapid delivery cycle. The study is focused on examining and analyzing the different possibilities of laser cutting of paper material in application area of complex low volume geometry cutting. The goal of this case was to analyze the feasibility of the laser cutting from technical, quality and implementation points of view and to discuss availability of new business opportunities.It was noticed that there are new business models still available within laser technology applications in complex geometry cutting. Application of laser technology, in business-to-consume markets, in synergy with Internet service platforms can widen the customer base and offer new value streams for technology and service companies. Because of this, existing markets and competition has to be identified, and appropriate new and innovative business model needs to be developed. And to be competitive in the markets, models like these need to include the earning logic and the stages from production to delivery as discussed in the paper.

Application of Laser Technology for Cutting Glass Articles

The work performed on laser cutting of glass articles at the Scientific-Research Institute of Technical Glass is described.

Management of hyperhidrosis.

Primary hyperhidrosis (HH), a condition of sweating in excess of thermoregulatory requirements, affects nearly 3% of the US population and carries significant emotional and psychosocial implications. Unlike secondary HH, primary HH is not associated with an identifiable underlying pathology. Our limited understanding of the precise pathophysiologic mechanism for HH makes its treatment particularly frustrating. However, a wide array of interventions for the treatment of HH have been implemented throughout the world. Herein, we discuss the most extensively studied therapeutic options for primary HH, including systemic oxybutynin, botulinum toxin injections, skin excision, liposuction–curettage, and sympathotomy/sympathectomy. We conclude with a discussion of possible future therapies for HH, including the applications of laser, microwave, and ultrasound technologies.

Femtosecond Laser Assisted Keratoplasty

Aim: To demonstrate application of femtosecond laser technology in patients with white cataract. Methods: Video-based description of successful management of intumescent white cataract with femtosecond laser technology. Results: We performed femtosecond laser assisted cataract surgery in multiple patients with different morphologies of white cataract. Successful completion of capsulotomy along with intraocular lens implantation in the bag was achieved in all the cases. No case had extension of capsulotomy upto the periphery. Conclusion: Femtosecond laser technology has revolutionized the management of difficult cataract case scenarios especially intumescent white cataract. Intraocular lens implantation in the bag with ideal capsular margin overlap can be achieved with ease in most cases.

Electronically tunable anion-π interactions in pyrylium complexes: experimental and theoretical studies.

Noncovalent interactions of anions with electron-deficient aromatic rings that have been studied so far involve non-heteroaromatic or nitrogen-based heteroaromatic systems. Here we report the first case of an organic oxygenated aromatic system, in particular the tri-aryl-pyrylium tetrafluoroborate system, for which noncovalent anion-π interactions of the pyrylium cation with the tetrafluoroborate anion have been experimentally detected and demonstrated by means of (19)F NMR spectroscopy in solution. A series of pyrylium tetrafluoroborate salts were synthesized in the presence of BF3·Et2O, by direct reaction of 4-substituted benzaldehydes with 4-substituted acetophenones or via the previously obtained chalcone of the less reactive ketone. Correlations of (19)F NMR chemical shifts of tetrafluoroborate anion for most of the synthesized tri-arylpyrylium tetrafluoroborate complexes with both the pyrylium cation molecular weight and the standard substituent Hammett constants, demonstrate anion-π(+) interaction to act between the polyatomic anion BF4(-) and the pyrylium aromatic system. DFT calculations reveal that an additional (C-H)(+)-anion hydrogen bond involving the H(5) of pyrylium ring exists for these fluorescent dyes that show a tunable cup-to-cap shape cavity. The strong fluorescence emission observed for some representative pyrylium tetrafluoroborates described herein, makes them a promising class of tunable emission wavelength dyes for laser technology applications.