CO2 Laser Exposure Research Articles

Configurable SNAP microresonators induced by axial pre-strain-assisted CO2 laser exposure.

Flexible engineering of the complex shapes of the surface nanoscale axial photonics (SNAP) bottle microresonators (SBMs) is challenging for future nanophotonic technology applications. Here, we experimentally propose a powerful approach for the one-step fabrication of SBMs with simultaneous negative and positive radius variations, exhibiting a distinctive "bump-well-bump" profile. It is executed by utilizing two focused and symmetrical CO2 laser beams exposed on the fiber surface for only several hundred milliseconds. The spectral characteristics of different eigenmodes are analyzed, providing deep insights into the complex physical processes during the CO2 laser exposure. The shapes of the SBMs can be flexibly adjusted by the exposure time, laser power, and applied pre-strains. As a proof of this technique, the developed approach enables the efficient production of a bat SBM, ensuring a uniform field amplitude of the bat mode over the length exceeding 120 µm with 7% deviation. Our proposed technique provides a powerful technique for the efficient fabrication of SBMs with predetermined shapes, laying the groundwork for its applications on microscale optical signal processing, quantum computing, and so on.

Efficacy of autologous adipose-derived stem cells and fractional carbon dioxide laser in the treatment of atrophic linear scars

Background Atrophic linear scars are scars that exhibit indentation or depression in the skin below the level of the surrounding tissues. Hyperpigmentation or hypopigmentation may be present. They are often caused by surgery, burns, and trauma. Objective To evaluate the efficacy of autologous adipose-derived stem cells (ADSCs) combined with fractional carbon dioxide (CO2) laser in the treatment of atrophic linear scars. Patients and methods This randomized, controlled preliminary study included 20 patients aged 20–45 years of both sexes with facial atrophic linear scars. The patients were randomized systematically into two groups: group A (combined ADSCs and fractional CO2 laser procedure) and group B (fractional CO2 laser only) of 10 patients each. The scar was evaluated using the Vancouver scar scale, along with a subjective satisfaction questionnaire, and ultrasound skin analysis at baseline and 1 month after the third treatment session. Results All participants completed the study. The mean Vancouver scar scale score improved significantly from 3.60±0.69 to 1.20±0.79 and from 2.20±1.03 to 1.60±0.52 with fractional CO2 laser plus ADSCs and CO2 laser procedure, respectively (P<0.001). However, CO2 laser plus ADSCs was significantly superior. Ultrasound skin examination showed a statistically significant increase in dermal collagen density (thickness) in both groups. Conclusion Our study shows that treatment with CO2 laser exposure plus ADSCs is safe and more effective for atrophic linear scar management than CO2 laser exposure alone.

Radiation Sensitive Long-Period Fiber Grating Based on Tb-Doped Silica Fiber

We demonstrate a radiation sensitive long-period fiber grating (LPG) based on terbium (Tb)-doped silica fiber, fabricated by dual-sided CO2 laser exposure. At a total dose of 6.0 ± 0.2 kGy of gamma radiation, the maximum radiation-induced resonance wavelength shift (RIRWS) of LPG in Tb-doped silica fiber is up to 3.98 nm, which is much higher than that of 1.14 nm in standard single-mode fiber. To characterize the degree of modification of fibers by radiation, we calculate the radiation-induced refractive index change (RIRIC), which is as high as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.05\times 10^{-5}$ </tex-math></inline-formula> for Tb-doped silica fiber, approximately 276.3% of that of standard single-mode fiber. In addition, the growth of RIRWS with increasing cladding mode order is analyzed, and the theoretical and experimental RIRWS of LPG are compared. This new type of LPG has great promise in the field of high-dose radiation sensing, such as dose monitoring in nuclear reactors, particle collision experiments, and so on.

CO2 lazerio parametrų įtaka beržinei fanerai skirtai reklamos produktų kūrimui

Wood is a material that is easy to recycle and quickly decomposes in nature, so replacing plastics with wooden products in advertising could contribute to sustainable development and ecology. Infrared CO2 lasers (beam wavelength 10.6 µm) are widely used for producing and processing wood and advertising products. Laser engraving of the material involves the destruction of the surface of the wood structure and the carbonisation process, during which a certain depth and colour of the engraved design are obtained. Changes in colour and depth are influenced by the type of wood and its thickness, laser power, energy flow density, and movement speed. In this research, the image prepared by the Adobe Illustrator program was imported into the RDWorks V8 computer program, connected to the Bodor BCL-MU CO2 laser used for engraving. After creating the test samples, the influence of technological parameters (speed and power) of CO2 laser exposure on the colour and surface morphology of birch plywood was analysed, and the correlation between ΔE and Ra parameters was determined using a spectrophotometric comparative analysis of surface colour tones and a three-dimensional (3D) morphology measurement method. The obtained results were discussed, visual material was demonstrated, and the most optimal work parameters were determined.

Local vasoregulative interventions impact drug concentrations in the skin after topical laser-assisted delivery.

The ability of ablative fractional lasers (AFL) to enhance topical drug uptake is well established. After AFLdelivery, however, drug clearance by local vasculature is poorly understood. Modifications in vascular clearance may enhance AFL-assisted drug concentrations and prolong drug dwell time in the skin. Aiming to assess the role and modifiability of vascular clearance after AFL-assisted delivery, this study examined the impact of vasoregulative interventions on AFL-assisted 5-fluorouracil (5-FU) concentrations in in vivo skin. 5-FU uptake was assessed in intactand AFL-exposed skin in a live pig model. After fractional CO2 laser exposure (15 mJ/microbeam, 5% density), vasoregulative intervention using topical brimonidine cream, epinephrine solution, or pulsed dye laser (PDL) was performed in designated treatment areas, followed by a single 5% 5-FU cream application. At 0, 1, 4, 48, and 72 h, 5-FU concentrations were measured in 500 and 1500 μm skin layers by mass spectrometry (n = 6). A supplemental assessment of blood flow following AFL ± vasoregulation was performed using optical coherence tomography (OCT) in a human volunteer. Compared to intact skin, AFL facilitated a prompt peak in 5-FU delivery that remained elevated up to 4 hours(1500 μm: 1.5 vs. 31.8 ng/ml [1 hour,p = 0.002]; 5.3 vs. 14.5 ng/ml [4 hours, p = 0.039]). However, AFL's impact was transient, with 5-FU concentrations comparable to intact skin at later time points. Overall, vasoregulative intervention with brimonidine or PDL led to significantly higher peak 5-FU concentrations, prolonging the drug's dwell time in the skin versus AFL delivery alone. As such, brimonidine and PDL led to twofold higher 5-FU concentrations than AFL alone in both skin layers by 1 hour(e.g., 500 μm: 107 ng/ml [brimonidine]; 96.9 ng/ml [PDL], 46.6 ng/ml [AFL alone],p ≤ 0.024), and remained significantly elevated at 4 hours(p ≤ 0.024). A similar pattern was observed for epinephrine, although trends remained nonsignificant (p ≥ 0.09). Prolonged 5-FU delivery was provided by PDL, resulting in sustained drug deposition compared to AFL alone at both 48 and 72 hoursin the superficial skin layer (p ≤ 0.024). Supporting drug delivery findings, OCT revealed that increases in local blood flow after AFL were mitigated in test areas also exposed to PDL, brimonidine, or epinephrine, with PDL providing the greatest, sustained reduction in flow over 48 hours. Vasoregulative intervention in conjunction with AFL-assisted delivery enhances and prolongs 5-FU deposition in in vivo skin.

Orthogonal long-period fiber grating for directly exciting the orbital angular momentum

An orthogonal long-period fiber grating (OLPFG) is proposed and demonstrated for directly exciting the orbital angular momentum (OAM), without the need for other devices. This grating was produced using CO2 laser exposure in the orthogonal direction. A helical phase was then optically induced in the OLPFG, with a chirality determined by the structure of the OLPFG. In this study, ±1-order OAM resonances were respectively observed in OLPFGs with a different orthogonal direction. The conversion efficiency of OAM mode in this process was 99%, and the purity was higher than 98%. In addition, incident light in any polarization state was observed to excite OAM with the same polarization.

Efficacy of platelet-rich plasma plus fractional carbon dioxide laser in treating posttraumatic scars.

The management of posttraumatic scars is a great challenge. Autologous platelet-rich plasma (APRP) and fractional carbon dioxide (CO2) laser can be applied as innovative treatments for posttraumatic scars. The aim of this study was to evaluate the efficacy, safety and complications of fractional CO2 laser exposure plus APRP injection in treating traumatic scars versus CO2 laser applied as a monotherapy. Twenty participants were treated 3 times at a 4-week interval with a follow-up visit. The scars were divided into an upper and lower half-treated with fractional CO2 laser exposure plus APRP injection and CO2 laser alone, respectively. The scar was evaluated using the Vancouver scar scale (VSS), along with patient satisfaction. Twenty patients completed the 3 month treatment course. The mean VSS score improved significantly from 7.0 ± 3.97 to 3.25 ± 1.55 and 6.75 ± 1.77 to 3.85 ± 1.59 with fractional CO2 laser exposure plus APRP injection and CO2 laser exposure, respectively (p < .001). However, CO2 laser plus APRP was significantly superior to CO2 laser alone (p = .001), with fewer adverse effects. Our study shows that combined treatment with CO2 laser exposure plus APRP injection is safer and more effective for posttraumatic scar management than CO2 laser exposure alone.

Fast sintering method of phosphor-in-glass for high-power LEDs

Fast sintering of Phosphor-in-Glass (PiG) by means of CO2 laser heating has been successfully achieved. PiGs samples fabricated at different exposure times were characterized and compared with a PiG sample synthetized through an electric furnace. An exposure time as short as 30 s and 12 W of optical power is necessary to sintering PiGs. Results show that the optimization of CO2 laser approach can dramatically reduce up to 60 times the PiGs sintering. Luminous Efficacy (LE) of at least 79.7 lm/W as well as minimum Color Rendering Index (CRI) value of 70 for all fabricated PiGs were obtained. Correlated Color Temperature (CCT) value decreased gradually as the CO2 laser exposure time increased. These results show that PiGs samples, synthetized with short exposure times, show excellent lighting properties.

Efficacy of silver diamine fluoride and combination with CO2 laser in reducing dentin hypersensitivity

Silver diamine fluoride application and CO2 laser exposure are new alternative treatments for dentin hypersensitivity. The purpose of this study was to evaluate the efficacy of silver diamine fluoride and CO2 laser in reducing the dentin hypersensitivity score. The study consisted of a single-blind, split-mouth design, and a randomized controlled trial involving 16 subjects with symptoms of sensitive teeth, with at least two hypersensitive teeth that were positive in evaporative or thermal tests. Silver diamine fluoride and CO2 laser were applied to the surfaces of the subjects’ teeth. This clinical study demonstrated that the application of silver diamine fluoride and CO2 laser reduced dentin hypersensitivity significantly (p = 0.000 for evaporative and thermal stimuli).

CO2 laser polishing of conical shaped optical fiber deflectors

A novel method for polishing conical shaped optical fiber deflectors by modulated CO2 laser exposure is reported. The conical shaped fiber deflector geometry was first formed with rough mechanical polishing, then it was exposed to modulated CO2 laser operating with wavelength at 10.6 µm to achieve fine polish surfaces. The motivation of this work is to demonstrate that the modulated CO2 laser exposure approach allows a fiber surface roughness at a nanometer scale without modifying the conical shape of the fiber deflector. The average surface roughness of mechanically polished fiber deflectors with 30 and 9 µm lapping films was smoothed down to 20.4 and 4.07 nm, respectively, after CO2 laser polishing process. By combining mechanical and laser polishing techniques, fabrication of conical shaped optical fiber deflectors takes less time and it becomes laborer independent and easy to apply.

Study of lateral-drilled DBR fiber laser and its responsivity to external refractive index.

We report a lateral-drilled DBR fiber laser which contains a defective parabola-like opening inside the cavity fabricated by the CO2-laser exposure and study the laser responsivity to external refractive index (RI). Surrounding materials can readily reach the vicinity of the fiber core via the opening and interact with the laser mode. Research shows that the laser emission power mainly relies on changes of external RI while the lasing wavelength on temperature. The effects of structural parameters, pump power, and external refractive index on the RI responsivity of the device are demonstrated. The lasing threshold condition is also concerned. This work provides an opportunity for controlling emission characteristics of the DBR fiber laser through modification of external RI value, of which the results are valuable for the potential applications in optical sensing, tunable lasing, and etc.

Rapid fibrin plug formation within cutaneous ablative fractional CO2 laser lesions.

Ablative fractional laser procedures have been shown to facilitate topical drug delivery into the skin. Past studies have mainly used ex vivo models to demonstrate enhanced drug delivery and in vivo studies have investigated laser created channels over a time course of days and weeks rather than within the first few minutes and hours after exposures. We have noticed rapid in vivo fibrin plug formation within ablative fractional laser lesions impairing passage through the laser created channels. In vivo laser exposures were performed in a porcine model. A fractional CO2 laser (AcuPulse™ system, AcuScan 120™ handpiece, Lumenis, Inc., Yokneam, Israel) was programmed in quasi-continuous wave (QCW) mode, at 40W, 50 mJ per pulse, 5% coverage, nominal 120 µm spot size, 8 × 8 mm square pattern, 169 MTZs per scan. Six millimeters punch biopsies were procured at 0, 2, 5, 10, 15, 30, 60, 90 minutes after completion of each scan, then fixed in 10% formalin. 12 repeats were performed of each time point. Skin samples were processed for serial vertically cut paraffin sections (5 μm collected every 25 μm) then H&E and special immunohistochemistry staining for fibrin and platelet. Dimensions of Microscopic Treatment Zones (MTZs) and extent of fibrin plug were assessed and quantified histologically. Ex vivo laser exposures of the identical laser parameter were performed on porcine and human skin at different storage conditions. Histology procured at various predetermined time intervals after in vivo fractional CO2 laser exposures revealed a rapidly forming fibrin plug initiating at the bottom of the MTZ lesions. At longer time intervals, the fibrin plug was extending towards the superficial sections. Within the first 5 minutes, more than 25% length of the entire laser-ablated channel was filled with a fibrin plug. With increased time intervals, the cavity was progressively filled with a fibrin plug. At 90 minutes, more than 90% length of the entire laser-ablated channel was occluded. Ex vivo exposures failed to produce any significant fibrin plug formation. The current study has demonstrated rapid fibrin plug formation after ablative fractional laser procedures. It was shown that the passage through laser created pathways is critically time dependent for in vivo exposures. In contrast, ex vivo exposures do not exhibit such time dependent passage capacity. In particular, drug, substance, and cell delivery studies for ablative fractional laser treatments should take early fibrin plug formation into consideration and further investigate the impact on transdermal delivery.

Study of the spectral features of different biological samples

In the present study we have observed and analyzed the fluorescence changes in the fluorescence spectra of four different samples like brilliant sulphaflanine, quinine bisulphate, coumarine 120 and porcine cornea and sclera including the changes in fluorescence spectrum of cornea are also observed after CO2 laser exposure. The preliminary study clearly explains the proof of concept only.

Spatially selective Er/Yb-doped CaF2 crystal formation by CO2 laser exposure

We report the glass–ceramic precipitation on the oxyfluoride glass surface by spatially selective annealing with a CO2 laser and a heat gun exposure. X-ray diffraction analysis showed the formation of major CaF2 and miner Ca2SiO4 nanoparticles. We observed ∼100nm nanoparticle aggregation by tunneling electron microscopy and element distribution in glass and crystal phases. Spatial distribution of glass ceramics near the glass surface was probed by confocal fluorescence microscope by using much enhanced emission from the Er ions in the laser-treated area. Strong emissions at 365nm excitation and visible up-conversion emissions at 980nm excitation also indicated well incorporation of Er and Yb ions into a crystalline environment.

Spatially selective Er/Yb-doped CaF2 crystal formation by CO2 laser exposure

We report the glass–ceramic precipitation on the oxyfluoride glass surface by spatially selective annealing with a CO2 laser and a heat gun exposure. X-ray diffraction analysis showed the formation of major CaF2 and miner Ca2SiO4 nanoparticles. We observed ∼100nm nanoparticle aggregation by tunneling electron microscopy and element distribution in glass and crystal phases. Spatial distribution of glass ceramics near the glass surface was probed by confocal fluorescence microscope by using much enhanced emission from the Er ions in the laser-treated area. Strong emissions at 365nm excitation and visible up-conversion emissions at 980nm excitation also indicated well incorporation of Er and Yb ions into a crystalline environment.

Flexible Fabrication of Long-Period Fiber Grating Devices Based on Erasing Effect by Controlled Co2 Laser Pulse Exposure

An easy way to flexibly fabricate special long-period fiber grating (LPFG) devices by controlled CO2 laser pulses are presented in this paper. By controlling the pulse power and duration, consecutive exposures were made on an optical fiber to fabricate an LPFG. Existing LPFGs can also be erased or modified by applying CO2 laser exposures on specific grating sections. The erasing effect has been studied to fabricate special grating devices for various applications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1735–1738, 2013

Effect of bending and orientation on the fiber modal mach–zehnder interferometer

AbstractBy introducing two notches along the fiber axis in a normal single‐mode fiber through CO2 laser exposure, a vector curvature sensor based on a modal Mach–Zehnder interferometer has been proposed and experimentally demonstrated.Transmission spectral response regarding the spectrum shift and transmission loss variation of the proposed sensor has been characterized and the experimental results show that due to the nonperfect circular geometry of the fiber cladding, the peak wavelength and the transmission loss of its spectrum are sensitive to applied bending orientation. Our proposed sensor has many advantages such as low cost, easy fabrication and good stability under harsh environment. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:136–139, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26471

A Prospective Study of Fractional Scanned Nonsequential Carbon Dioxide Laser Resurfacing

Although unparalleled in its efficacy, carbon dioxide (CO2) laser resurfacing has a high risk:benefit ratio. A modified device uses a novel handpiece and software to deliver nonsequential fractional ablative CO2 laser exposures. To evaluate the safety and efficacy of this fractional ablative, scanned, nonsequential CO2 laser in the treatment of photo-damaged skin and to evaluate histologic and ultrastructural changes after the treatment. Ten subjects with Fitzpatrick skin types I to III with photo-damaged facial skin underwent a single CO2 ablative laser treatment using a scanning handpiece in a nonsequential fractional mode. Clinical improvement and histologic and ultrastructrural changes were assessed. All subjects completed the study with no serious or long-term complications. Blinded evaluator and subject assessment documented improvement in cutaneous photoaging. Light microscopy revealed changes consistent with a wound repair mechanism, and electron microscopy confirmed evidence of new collagen deposition. Nonsequential scanned fractional CO2 laser resurfacing can lead to improvement in photo-damaged skin, accompanied by histologic and ultrastructural evidence of wound repair and subsequent new collagen formation.

Long-period fibre gratings written by CO 2 exposure of H 2 -loaded,standard fibres

High quality long-period gratings have been written in standard fibres pre-H2-loaded, using CO2 laser exposure at low intensity. The formation of OH bonds in the fibre core probably explains the index change when such a moderate intensity exposure is applied.

Ultrastructure of collagen thermally denatured by microsecond domain pulsed carbon dioxide laser.

Clinical improvement in photodamaged skin after carbon dioxide (CO2) laser resurfacing is thought to result in part from thermal collagen shrinkage. The presence of such collagen has not been unequivocally demonstrated. To identify and characterize the morphological features of collagen after CO2 laser exposure, we irradiated ex vivo human facial skin and bovine calcaneus tendon with microsecond domain pulsed CO2 laser energy and examined specimens for histopathological and ultrastructural changes in collagen. In dermis and tendon, 3 zones of collagen structure were apparent on electron microscopy. The first, most superficial zone demonstrated loss of collagen structure. The second zone consisted of admixed normal collagen fibers and thickened collagen fibers. Zone 3 consisted of normal-appearing collagen fibers. Ultrastructural examination of irradiated collagen revealed distinct morphological zones of denatured collagen fibers. Partially denatured fibers had an increased diameter consistent with lineal shrinkage. Zonal distinction was undetectable by light microscopy. Ultrastructurally, the zones of denatured collagen located above the normal fibers correlated with the zone of altered material seen on light microscopy. These findings suggest that collagen fiber shrinkage does occur after pulsed CO2 laser irradiation and that this phenomenon contributed, at least in part, to the immediate tissue contraction observed clinically.