Variety Of Lasers Research Articles

Modelling System Parameters for Improvised Performance in Free Space Optics (FSO) Networks

Free space optics (FSO) is a remote method for correspondence that send information by means of an optical source. The medium among transmitter and recipient is a free space that has an away from of sight for imparting the sign. Air, vacuum, and space can go about as free space. Establishment of this framework is financially savvy contrasted with different frameworks and can be set up with in less time. The upside of this framework is it can send a lot of information because of high transmission capacity. A portion of the components which influence the transmission of FSO are downpour, mist, fog and actual obstacles. Two FSO joins are planned in this paper one with a variety of laser and one with a solitary laser, we are going to investigation the Max. Q along with the Bit error rate esteem for the two frameworks at various constrictions. Multiplexing of the signals is carried out to estimate the performance of the system. Due to the use of multiplexing high bit rates are achieved. The link distance under consideration for this experimental simulation was at 10 km which includes various power levels of the laser. Performance of the two links is compared in the results with the parameter of BER at various power levels by using BER analyzer.

Monitoring the effectiveness of nanosecond laser for the treatment of port-wine stain patients using non-invasive imaging systems

A variety of lasers have been used to treat port-wine stain (PWS) birthmarks, however, all of them carry the risk of adverse effects. Our objective was to assess the effectiveness and safety of nanosecond (ns) laser treatment for PWS patients using non-invasive images. This study included 20 PWS patients, whose ages ranged from one to sixteen years. A nanosecond laser (λ=595 nm; τp=2 ns), with a spot size of 5 mm, and parameters of 0.2-0.3 J/cm2, 5 Hz, was used in three passes. The infrared thermal imager aided in determining the optimal laser dosage and preventing side effects. The primary efficiency was evaluated using a DermaSpectrometer, and patients were followed up after one week, four weeks, three months, and twelve months. The infrared thermal images of skin surface temperature assessment in the first ten seconds were recorded after the maximal energy density 0.3 J/cm2 treatment. The thermal wave equation and Penne’s bioheat transfer equation ranged from 32.4±0.1 to 33.8±0.2°C, 32.6±0.1 to 34.7±0.3°C (baseline skin surface temperature - 32.4±0.3°C) respectively. Transient hyperpigmentation appeared in 5% (n=1) of the 20 patients, but it resolved spontaneously within three months. There was no evidence of permanent hypopigmentation or scarring. The DermaSpectrometer revealed a 30% reduction in Hb-index three months after a single treatment. The infrared image instrument is helpful in determining the optimum laser dosage. For the treatment of PWS patients, a nanosecond pulsed laser at 595nm was effective and safe.

Prospective study of efficacy and safety of non-ablative 1927 nm fractional thulium fiber laser in Asian skin photoaging.

Photoaging manifests as deeper wrinkles and larger pores. It has been tried to rejuvenate photoaging skin using a variety of lasers, including fractionated lasers, which are a popular photorejuvenation treatment. A new breakthrough for skin rejuvenation is the 1927 nm fractional thulium fiber laser (FTL), a laser and light-based treatment option. Clinical data regarding the FTL for treating photoaging are limited despite its effectiveness and safety. This study is aim to evaluate FTL' clinical effectiveness and safety. Fitzpatrick skin types II-IV subjects with mild to moderate photoaging signs were enrolled in this prospective study. At intervals of one month, patients received three full face treatments. Wrinkles, spots, texture, pores, melanin index, erythema index (MI and EI), skin elasticity and hydration were measured with non-invasive tool. The epidermal thickness and dermal density on ultrasonography were compared between baseline and one month after all treatment sessions. The Global Score for Photoaging scale (GSP) was rated by two independent evaluators at the baseline and final follow-up visit. Secondary outcomes included patient-rated pain on a 10-point visual analog scale (VAS), as well as overall satisfaction. Following each treatment, adverse events were noted. Totally 27 subjects (24 females and 3 males) with Fitzpatrick skin types II to IV and a mean age of 44.41 (range33-64) were enrolled. Results suggests that the epidermal thickness has significantly improved after treatment. Statistically significant improvements in melanin index, skin elasticity and wrinkles were noted. An analysis of 12 subjects' reports (44%) suggested their skin felt brighter. No post-inflammatory hyperpigmentation changes or adverse events were observed. 70% patients reporting "satisfied" or "extremely satisfied". In this study, FTL was found to be a safe and effective treatment option for treating photoaging.

Analysis of the Effect of Nd:YAG Laser Irradiation on Soft Tissues of the Oral Cavity in Different Modes in an In Vivo Experiment

The development of laser medicine has led to its use in dentistry further to improve existing treatment methods, including surgical techniques. The variety of lasers allows them to be used for procedures on the soft and bone tissues of the oral cavity as well as on the tissues of the teeth. The short duration of laser pulse action on tissues, selective action on pathological tissues in a sterile surgical field, and activation of local and humoral immunity of the oral cavity provides an increase in the regeneration potential of tissues of the postoperative area, which contributes to the shortening of wound process phases, favorable course of the postoperative period, and shortening of the healing time. Our article presents the experience of using the Nd:YAG laser in different modes in replicating the effect of curettage of periodontal pockets in an experiment on laboratory animals. According to the study results, there was a difference in the healing time of soft tissues after their exposure to several modes of the Nd:YAG laser, which makes it possible to recommend each of them for individual clinical cases.

Updates and Best Practices in the Management of Facial Erythema.

Facial erythema is a common dermatologic complaint. There are many medical and procedure-based treatments to help reduce the appearance of unwanted facial redness. The authors review a variety of treatment options and techniques to reduce facial erythema and prominent facial veins including topical medical therapies, a variety of lasers, light- and energy-based devices as well as the use of neuromodulators and sclerotherapy. The benefits and potential pitfalls of each procedure modality are also highlighted.

Femtosecond ionization mass spectrometry for chromatographic detection

Mass spectrometry is now in widespread use for the detection of the analytes separated by chromatography. Electron ionization is the most frequently used method in mass spectrometry. However, this ionization technique sometimes suffers from extensive fragmentation of analytes, which makes identification difficult. A photoionization technique has been developed for suppressing this fragmentation and for subsequently observing a molecular ion. A variety of lasers have been employed for the sensitive and selective ionization of organic compounds. A femtosecond laser has a high peak power and is preferential for efficient ionization as well as for suppressing fragmentation, providing valuable information concerning molecular weight and chemical structure as well. In this review, we report on applications of femtosecond ionization mass spectrometry combined with gas chromatography.

Clinical and Dermoscopic Features of Follicular Becker's Nevus: A Rare Variant.

Sir, Becker's nevus is a cutaneous hamartoma, typified by the presence of macular pigmentation, hypertrichosis, and smooth muscle proliferation. Herein, we report a rare follicular variant of Becker's nevus. An 18-year-old man presented with asymptomatic lesions over the right chest and supraclavicular area for a year and a half, gradually progressive in nature. There were no lesions elsewhere. There was no history of seizures, developmental delay, or any neurological complaints. On examination, there was unilateral involvement of the right upper chest and supraclavicular area in the form of numerous, well-defined, folliculocentric macules tending to coalesce at one side [Figure 1a and b]. There was no evidence of scaling, and scratch sign was negative. There was presence of terminal hair in the patch located at the centre of each hyperpigmented macule. There was no evidence of thickening or nodularity over the lesion. There was no limb or breast hypoplasia or asymmetry.Figure 1: (a and b) Numerous, hyperpigmented, folliculocentric macules seen over the right side of the chest, extending onto the neck as well as the shoulder. They tend to be coalescing towards the centerDermoscopy (Dermlite DL200 Hybrid M; polarized mode) showed a well-defined network-like pigmentation. There was immediate perifollicular hypopigmentation., visible dermoscopically. Surrounding this, there were well-defined areas of darker pigment network. These corresponded clinically to the folliculocentric macules [Figures 2 and 3].Figure 2: Dermoscopy (Dermlite DL200 Hybrid M; polarized mode) showed islands of well-defined network-like pigmentation. Interspersed between these islands were areas of normal skin with a normal skin pigment networkFigure 3: Dermoscopy (Dermlite DL200 Hybrid M; polarized mode) showing immediate perifollicular hypopigmentation, surrounding which there is a hyperpigmented area around each individual follicle. This corresponds clinically to hyperpigmented macules, thus, representing the follicular variantHistopathology demonstrated hyperpigmentation of the basal layer with regular elongation of rete ridges. There was acanthosis present. This hyperpigmentation corresponds clinically to the hyperpigmented macules. There was no evidence of dermal smooth muscle proliferation. Thus, a final diagnosis of follicular Becker's nevus was made. The patient was counselled about the nature and course of the condition and advised treatment with Q-switched NDYAG laser. However, because of the lack of facilities in the government institute where he presented and him not being able to afford private treatment, the patient did not opt for this. Becker's nevus is a cutaneous hamartoma, presenting as a unilateral patch of hyperpigmentation, with hypertrichosis and smooth muscle proliferation. The exact etiology of Becker's nevus is unknown. Beta-actin (ACTB) mutations amplify Hedgehog signaling leading to interference with the development of hair follicles and arrector pili muscles. This explains lesions being perifollicular, to begin with.[1] Androgens play a role in this condition as seen by peri-pubertal development, hypertrichosis, acneiform lesions in the involved area, and hypertrichosis, with an increase in androgen receptors in the involved skin noted.[2] Several morphological variants of Becker's nevus reported include the presence of only pigmentation (Becker's melanosis), giant Becker's nevus, blaschkoid Becker's nevus, bilateral involvement, and presence of multiple lesions. Becker's nevus syndrome is an association of Becker's nevus with unilateral breast hypoplasia and muscle, skin, and/or skeletal abnormalities.[3] There is a case series on follicular Becker's nevus by Y Manchanda et al.,[4] describing predominantly follicular involvement. It is suggested that the presence of folliculocentric macules at the periphery of evolved lesions, and the center of early lesions points to an etiopathological role of the follicular epithelium. In contrast to the dermoscopy of classical Becker's nevus in which a continuous sheet of pigmentation is seen, islands of pigmentation are seen in the case of follicular Becker's nevus. On dermoscopy of classical Becker's, the well-defined pigment network is present in a continuous sheet, with uniform thickness and color of lines throughout the lesion. In follicular Becker's, the pigmentation is patchy – occurring in circles around each follicle. Interspersed between these circles are areas of normal pigment network i.e., normal skin. It can often pose a diagnostic conundrum, being misdiagnosed as pityriasis versicolor. It is important to note that early and evolving lesions of Becker's nevus can present with only predominantly follicular lesions. The lack of scaling and unilateral location along with the dermoscopic findings can help differentiate the two. A variety of lasers have been used alone or in combination to treat the hyperpigmentation and hypertrichosis of Becker's nevus, with wavelengths ranging from 504 to 10,600 nm.[5] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

A Comparative Study of Laser-Induced Graphene by CO2 Infrared Laser and 355 nm Ultraviolet (UV) Laser.

Laser-induced graphene (LIG) is an emerging technique for producing few-layer graphene or graphene-like material that has recently received increasing attention, due to its unique advantages. Subsequently, a variety of lasers and materials have been used to fabricate LIG using this technique. However, there is a lack of understanding of how different lasers (wavelengths) perform differently in the LIG conversion process. In this study, the produced LIG on polyimide (PI) under a locally water-cooled condition using a 10.6 μm CO2 infrared laser and a 355 nm ultraviolet (UV) laser are compared. The experimental investigations reveal that under the same UV and CO2 laser fluence, the ablation of PI show different results. Surface morphologies with micron-sized and nanometer pores were formed by the UV laser under different laser fluences, whereas micron-sized pores and sheet structure with fewer pores were produced by the CO2 laser. Energy dispersive spectrometry and three-dimensional topography characterization indicate that the photochemical effects were also involved in the LIG conversion with UV laser irradiation. It is also observed through experiments that the photothermal effect contributed to the formation of LIG under both lasers, and the LIG formed on PI substrates by the CO2 laser showed better quality and fewer layers.

Lasers in Glaucoma: an Overview.

Lasers have been in use as a treatment modality of glaucoma for more than last four decades. Each passing year has added newer dimensions to the existing laser technologies enhancing their safety and efficacy profile. This has become possible due to continuous research and innovations with proper understanding of the mechanism of action of different variety of lasers as treatment options. Each category of glaucoma has different underlying pathologies. Adequate knowledge and understanding of indications, limitations and hazards of these laser procedures are must before their application for improvising outcome. Recent years have witnessed a revolution this field. A thorough literature search was conducted in PubMed, Medline, the Cochrane Library Database, EMBASE, and Scopus and Google Scholar until May 2020 using the keywords, and all the articles pertaining to the relevant topics were included in this review. Purpose of this review is to summarize the important laser procedures currently in use for managing glaucoma along with updating the readers with recent advances in laser technologies, their extended applications and also analyzing possible future implications.

Quantum-stochasticity-induced asymmetry in the angular distribution of electrons in a quasiclassical regime

Impacts of quantum stochasticity on the dynamics of an ultra-relativistic electron beam head-on colliding with a linearly polarized ultra-intense laser pulse are theoretically investigated in a quasi-classical regime. Generally, the angular distribution of the electron beam keeps symmetrically in transverse directions in this regime, even under the ponderomotive force of the laser pulse. Here we show that when the initial angular divergence $\Delta \theta_i \lesssim 10^{-6} a_0^2$ with $a_0$ being the normalized laser field amplitude, an asymmetric angular distribution of the electron beam arises due to the quantum stochasticity effect, via simulations employing Landau-Lifshitz, quantum-modified Landau-Lifshitz equations, and quantum stochastic radiation reaction form to describe the radiative electron dynamics respectively. The asymmetry is robust against a variety of laser and electron parameters, providing an experimentally detectable signature for the nature of quantum stochasticity of photon emission with laser and electron beams currently available.

Optical tracking and laser-induced mortality of insects during flight

Addressing the need for novel insect observation and control tools, the Photonic Fence detects and tracks mosquitoes and other flying insects and can apply lethal doses of laser light to them. Previously, we determined lethal exposure levels for a variety of lasers and pulse conditions on anesthetized Anopheles stephensi mosquitoes. In this work, similar studies were performed while the subjects were freely flying within transparent cages two meters from the optical system; a proof-of-principle demonstration of a 30 m system was also performed. From the dose–response curves of mortality data created as a function of various beam diameter, pulse width, and power conditions at visible and near-infrared wavelengths, the visible wavelengths required significantly lower laser exposure than near infrared wavelengths to disable subjects, though near infrared sources remain attractive given their cost and retina safety. The flight behavior of the subjects and the performance of the tracking system were found to have no impact on the mortality outcomes for pulse durations up to 25 ms, which appears to be the ideal duration to minimize required laser power. The results of this study affirm the practicality of using optical approaches to protect people and crops from pestilent flying insects.

Direct laser writing of graphene electrodes

Direct laser writing of graphene electrodes is an emerging research field for the rapid fabrication of two-dimensional carbon electronic materials with wide applications, ranging from supercapacitors and batteries to sensors, electrocatalysts, actuators, etc. Many types of carbon-containing raw materials can be converted to graphene by one-step laser scribing, without complicated chemical synthesis routines, using a variety of lasers. This perspective categorizes the principles of direct laser writing of graphene, according to the different types of raw materials, different types of lasers, and different applications. The future directions of laser synthesized graphene are also discussed.

Structured Light from Lasers

AbstractStructured light is derived from the ability to tailor light, usually referring to the spatial control of its amplitude, phase, and polarization. Although a venerable topic that dates back to the very first laser designs, structuring light at the source has seen an explosion in activity over the past decade, fuelled by a modern toolkit that exploits the versatility of diffractive structures, liquid crystals, metasurfaces/metamaterials, and exotic laser geometries, as well as a myriad of applications that range from imaging, microscopy, and laser material processing to optical communication. Here, the recent progress in creating and controlling structured light is reviewed, with particular emphasis on structuring light at the source: structured light lasers. The various design approaches, including pump shaping, cavity geometries, and the use of custom intracavity optical elements, implemented in a variety of lasers from microchip solutions to high‐power fibers are covered in a tutorial style. The history and latest developments in the field are reviewed, elucidating the various structured light patterns that have been created from lasers, including orbital angular momentum and vector states of light. Finally, the present challenges and limitations are highlighted, along with comments on likely future trends.

The effect of 1540‐nm fractional erbium‐glass laser in the treatment of androgenic alopecia

Androgenic alopecia is common, chronic dermatologic disorder. A variety of lasers and light sources appear to be safe and effective in the treatment of AGA. To evaluate the efficacy and safety of 1540-nm fractional erbium glass laser in the treatment of AGA. This was an interventional therapeutic study for the treatment of patients with AGA. The patients received 10 sessions with 1540-nm fractional erbium glass laser at 2-week intervals. The assessment of the response was done before and at the end of follow-up period, both objectively (the change in the density of terminal hair and the diameter of the hair shaft) and subjectively (patient satisfaction). Any adverse effects were documented during the study. Forty-seven out of 51 patients completed the study. After 5months of laser treatment, the density of hair and hair thickness was significantly increased in both males and females (P value .001). The 1540-nm fractional erbium-glass laser seems to be an effective and safe option for treatment of patients with AGA. The improvement was accomplished in a short period.

Lasers for Becker's nevus.

Becker's nevus is a common pigmented dermatosis, usually featured by ipsilateral pigmented patch with hypertrichosis. Becker's nevus is often treated with various types of lasers although other regimens are available. However, clinical outcomes appear inconsistent among studies. To summarize the clinical outcomes of Becker's nevus treated with lasers via literature review. A variety of lasers had been used alone or in combination to treat Becker's nevus. Laser wavelengths used for Becker's nevus ranged from 504 to 10,600nm, while the number of treatment varied from 1 to 12 sessions. The clinical outcomes were mixed although combination of lasers with different wavelengths appeared to achieve a better efficacy. Adverse effects were usually mild to moderate erythema. While lasers are relatively safe, their efficacy for Becker's nevus is moderate. It seems that combination therapy could improve the outcome. However, trials in larger group of patients are required to validate the efficacy of each type of lasers for Becker's nevus.

I256] A review of medical laser accidents: A simple burn to death by laser

After the invention of the laser by Maiman in 1960, Ophthalmology took advantage of the laser immediately and reported the first use of a medical laser in 1963 to replace the filament light source and improved the accuracy of photocoagulation for the treatment of diabetic retinopathy. In the past 60 years, a variety of lasers are used in many medical specialties such as ophthalmology, gynaecology, urology ENT and maxilo-facial surgery. Millions of safe laser procedures are carried out annually throughout the world. Despite international guidelines, regulations and local safety measures and procedures, adverse events (also known as accidents) do happen and result in undesirable consequences. In recent years, due to medical lasers becoming inexpensive, there is a massive increase in their use for cosmetic applications such as skin rejuvenation, hair removal and tattoo removal. In many countries, use of cosmetic lasers is unregulated and is carried out mostly by non-medical personnel.The main cause of laser accidents is due to human error, particularly not following safety procedures. Both patients and laser users become the victims of tissue damage due to unwanted laser exposure. Most laser accidents in literature report damage to skin and eye. As lasers do not penetrate much into the skin, most injuries occur as burns leading to swelling and pain followed by scars. As the eye is transparent to visible and some invisible light (UV and near infrared), lasers can cause irreversible and permanent damage in the eye and lead to blindness. Simple laser burns are usually unreported due to the fear of being blamed for the mistake. Litigation law suits against cosmetic laser treatments such as laser hair removal and tattoo removal are on the rise. Furthermore, few laser accidents report fire due to combustible material in their path. High voltage employed in some lasers such as CO2 and copper vapour lasers can result in electric shock. Even though rare, there are few reported cases of laser accidents resulting in death. This presentation is a review of all reported and unreported events.

Rejuvenation of the Aging Arm

The aging arm is characterized by increased dyspigmentation, a proliferation of ectactic blood vessels, excessive adiposity, excessive skin laxity, and actinic keratosis. A variety of laser, energy, and surgical techniques can be used to improve these features. The objective of this article is to describe the treatment modalities that have proven efficacious in rejuvenating the aging arm and combination therapies that have the potential to optimize patient outcomes while maintaining safety and tolerability. A Medline search was performed on nonsurgical aesthetic combination treatments because it relates to arm rejuvenation, and results are summarized. Practical applications for these combination treatments are also discussed. Although there is significant evidence supporting the effective use of nonsurgical treatments for arm rejuvenation, little in the literature was found on the safety and efficacy of combining such procedures and devices. However, in the authors' clinical experience, combining arm rejuvenation techniques can be done safely and often result in optimal outcomes. Arm rejuvenation can be safely and effectively achieved with combination nonsurgical aesthetic treatments.

Laser and Light Treatments for Striae Distensae: A Comprehensive Review of the Literature.

Striae distensae (SD) are common dermatologic lesions that often arise as a result of rapid weight change, certain endocrine conditions, or prolonged exposure to steroids. SD initially present as raised edematous plaques (striae rubra), after which they become white and atrophic (striae alba) owing to local breakdown and reorganization of collagen and elastin. There currently exists no reliable treatment option, though numerous topical applications have been attempted. Lasers and light represent emerging noninvasive therapies that have demonstrated some success targeting vascular chromophores in striae rubra and stimulating collagen and elastin production in striae alba. An extensive literature review was performed to gather all available articles studying laser and light treatments for SD. Lasers and light can significantly improve the appearance of both striae rubra and striae alba. Generally, striae rubra are more responsive to therapy and can be treated successfully with a variety of lasers without major adverse effects. Fractional lasers exhibit the strongest results for striae alba repigmentation and collagen induction, and several other lasers produce temporary repigmentation. Lasers in combination with other modalities such as topical agents and additional energy devices have also demonstrated promising preliminary results; however, large comparative studies are necessary to validate these outcomes.

Infraorbital dark circles: A review of the pathogenesis, evaluation and treatment

Infraorbital dark circles represent a common and multifactorial challenge in the world of aesthetic medicine and are the result of a variety of factors including deep facial anatomy, soft tissue changes, as well as contributions from the skin. A variety of treatment options exist, and a customised management strategy can be developed for the particular anatomic changes present. A literature search using MEDLINE and non-MEDLINE sources was performed utilising keywords including: ‘Dark circles’ ‘infraorbital dark circles’, ‘infraorbital pigment’, ‘under-eye circles’ and ‘lower eyelid bags’. A comprehensive review of the literature was performed and the data were assimilated with evidence from our practice. This review provides a detailed discussion of the aetiology, pathogenesis, evaluation and management of infraorbital dark circles. An understanding of the deep and superficial anatomy is crucial to the management of this complex entity. The armamentarium for treatment includes minimally invasive interventions such as makeup and cosmeceuticals, a variety of laser and chemical treatments, fillers and fat transfer, as well as more invasive surgical manoeuvres.

Assessment of efficacy and tolerability of different concentrations of trichloroacetic acid vs. carbon dioxide laser in treatment of xanthelasma palpebrarum.

There are numerous methods currently available for the management of xanthelasma. These include surgical excision, laser ablation using a variety of lasers and chemical cauterization. However, each method of treatment is associated with particular limitations and side effects. To assess the clinical efficacy and tolerability of different concentrations of topical trichloroacetic acid (TCA) vs. carbon dioxide laser in the treatment of patients with xanthelasma palpebrarum. Thirty patients with xanthelasma palpebrarum were classified into four groups, treated by TCA 35%, 50%, 70%, and CO2 laser, respectively. Lipid profile was estimated for all patients. Both TCA peeling 70% and carbon dioxide laser ablation showed more significant clinical efficacy and tolerability with least number of sessions in the treatment of xanthelasma palpebrarum than 50% and 35% TCA peeling. Post-therapy erythema and hypopigmentation were more with TCA 70%. Post-therapy hyperpigmentation was more with TCA (50%). There was a significant improvement in patients with normal lipid profile than those with abnormal profile. Both TCA peeling 70% and carbon dioxide laser ablation are highly effective and well tolerated with least number of sessions in the treatment of xanthelasma palpebrarum.