CO2 Laser System Research Articles

Efficacy of Topical Hydroxypinacolone Retinoate-Peptide Product Versus Fractional CO2 Laser in Facial Aging.

Many people are interested in addressing visible signs of aging with non-invasive cosmetic treatments. Development of effective topical products will provide options to delay or support cosmetic procedures. This study assessed and compared the efficacy and tolerance of a topical product used over the course of 16 weeks to a single ablative laser treatment on women with moderate global photodamage on the face. Subjects in Cell 1 (Laser Cell) were treated over the entire face with a fractional CO2 laser system. Subjects in Cell 2 (Topical Serum Cell) were treated with a topical serum containing hydroxypinacolone retinoate and peptides over the entire face, twice per day for 16 weeks. The study was composed of 71 women, with 29 in the Laser Cell (mean age 56.2) and 42 in the Topical Serum Cell (mean age 55.0), between 40 and 65 years old. Expert grading was used to determine efficacy parameters. Participants in the Topical Serum Cell achieved more significant improvement (p < 0.05) in Marionette lines, fine lines (global face), wrinkles (global face), wrinkles (crow's feet), nasolabial folds, texture, smoothness (tactile), global hyperpigmentation, lift, and photodamage compared to participants in the Laser Cell. Participants in the Topical Serum Cell achieved parity in the look of fine lines (crow's feet), forehead lines, glabella, firmness/bounce (tactile), skin tone evenness, radiance. While no statistically significant differences in tolerability were observed, treatment with the topical cosmetic product achieved parity or statistically better improvement in parameters compared to laser treatment at 16 weeks.

A faster CO2 fractional scanner system mode for skin rejuvenation. A clinical study.

The market requires ever-faster techniques, in particular for pre-rejuvenation condition. The purpose of this study was to assess if a fractional CO2 scanner modality (called moveo) results in a faster full-face rejuvenation treatment in comparison to the standard mode, currently existing in the scanner system. A total of 12 female patients affected by fine lines participated in a split-face clinical investigation and underwent to two sessions with a fractional CO2 laser system equipped with an existing and a faster dedicated scanner units. Pain was assessed using VAS. Three-dimensional clinical photographs were captured before, immediately after, 3 days, 14 days after the first treatment and immediately after the second treatment and 1 months after the last one. The uniformity and aesthetic coverage of treatments were assessed using dermatoscopy. Global aesthetic improvement scale (GAIS) was used. The time taken to treat the two sides of the face and all possible side effects were monitored. Following only two treatment session with both scanner modes, the patient's skin texture improved significantly, with fine lines reduction. There is no statistically significant difference in perceived pain between patients. The GAIS score showed satisfactory results following both modalities. The time parameters indicated that with the faster scanner mode the full-face treatment time was reduced by 30% compared to the standard one. No adverse effects were observed. The moveo modality provide faster treatment and a better final dermal aesthetic outcome than the standard procedure while maintaining the same safety profile.

Spectral characterization of a Cryo-Cooled CO laser operating with CO2 laser gas mixture

This study explores the emission spectra and performance characteristics of a cryo-cooled CO laser system operating with CO2 laser gas mixture under various operating conditions, viz., N2 free gas mixture, different coolant temperatures and in grating tuned configuration. The narrow operational window in case of N2 free gas mixture, increased output power and richer emission spectrum obtained with the addition of N2 gas indicates enhanced discharge stability and efficient excitation in presence of Nitrogen. The emission spectrum revealed shifting of the trapping levels towards lower vibrational quantum number with reducing coolant temperature and the same was also corroborated by theoretical calculations. No lasing was observed for vibrational levels V>15 which is attributed to the higher partial pressure of oxygen inherently present in the gain medium formed due to dissociation of CO2. The system lased on more than 20 transitions in grating tuned configuration with power exceeding 100mW on several lines. The presence of higher concentration of O2 in the discharge prevents carbon deposition − a common issue in CO lasers. This study underscores the significance of this unconventional CO laser system offering reliable operation in the 5 µm wavelength region without the usage of extraneous CO gas.

Batch-to-Batch Variation in Laser-Inscribed Graphene (LIG) Electrodes for Electrochemical Sensing.

Laser-inscribed graphene (LIG) is an emerging material for micro-electronic applications and is being used to develop supercapacitors, soft actuators, triboelectric generators, and sensors. The fabrication technique is simple, yet the batch-to-batch variation of LIG quality is not well documented in the literature. In this study, we conduct experiments to characterize batch-to-batch variation in the manufacturing of LIG electrodes for applications in electrochemical sensing. Numerous batches of 36 LIG electrodes were synthesized using a CO2 laser system on polyimide film. The LIG material was characterized using goniometry, stereomicroscopy, open circuit potentiometry, and cyclic voltammetry. Hydrophobicity and electrochemical screening (cyclic voltammetry) indicate that LIG electrode batch-to-batch variation is less than 5% when using a commercial reference and counter electrode. Metallization of LIG led to a significant increase in peak current and specific capacitance (area between anodic/cathodic curve). However, batch-to-batch variation increased to approximately 30%. Two different platinum electrodeposition techniques were studied, including galvanostatic and frequency-modulated electrodeposition. The study shows that formation of metallized LIG electrodes with high specific capacitance and peak current may come at the expense of high batch variability. This design tradeoff has not been discussed in the literature and is an important consideration if scaling sensor designs for mass use is desired. This study provides important insight into the variation of LIG material properties for scalable development of LIG sensors. Additional studies are needed to understand the underlying mechanism(s) of this variability so that strategies to improve the repeatability may be developed for improving quality control. The dataset from this study is available via an open access repository.

Green Fabrication of Stackable Laser‐Induced Graphene Micro‐Supercapacitors under Ambient Conditions: Toward the Design of Truly Sustainable Technological Platforms

AbstractExtensive research into green technologies is driven by the worldwide push for eco‐friendly materials and energy solutions. The focus is on synergies that prioritize sustainability and environmental benefits. This study explores the potential of abundant, non‐toxic, and sustainable resources such as paper, lignin‐enriched paper, and cork for producing laser‐induced graphene (LIG) supercapacitor electrodes with improved capacitance. A single‐step methodology using a CO2 laser system is developed for fabricating these electrodes under ambient conditions, providing an environmentally friendly alternative to conventional carbon sources. The resulting green micro‐supercapacitors (MSCs) achieve impressive areal capacitance (≈7–10 mF cm−2) and power and energy densities (≈4 μW cm‐2 and ≈0.77 µWh cm−2 at 0.01 mA cm−2). Stability tests conducted over 5000 charge–discharge cycles demonstrate a capacitance retention of ≈80–85%, highlighting the device durability. These LIG‐based devices offer versatility, allowing voltage output adjustment through stacked and sandwich MSCs configurations (parallel or series), suitable for various large‐scale applications. This study demonstrates that it is possible to create high‐quality energy storage devices based on biodegradable materials. This development can lead to progress in renewable energy and off‐grid technology, as well as a reduction in electronic waste.

CO2 Laser Frenuloplasty: Advancing Minimally Invasive Techniques for Rapid Healing and Improved Patient Outcomes

This study explores the innovative use of CO2 laser technology in frenuloplasty, a significant shift from classic methods like scalpel surgery or electrocautery towards a minimally invasive approach. The research involved 15 patients aged 25 to 50, undergoing frenuloplasty with a CO2 laser system equipped with a 7-inch defocused handpiece, set at 20 Hz and 0.3 W. This method diverges from conventional laser techniques, focusing on controlled laser passes combined with manual traction to elongate the fibrous tissue of the frenulum. The results demonstrated that the CO2 laser technique allowed for a precise and progressive modification of the frenulum, significantly reducing the risks of hemorrhage and secondary intention fibrosis. The healing process was notably expedited, with patients reporting satisfactory outcomes within a two-week period. Statistically significant improvements were observed in patient-reported outcomes, as evidenced by the increases in the Short Form Health Survey (SF-12) scores, with the mean Physical Component Summary (PCS) score rising from 32.5 to 47.5 and the mean Mental Component Summary (MCS) score from 39.3 to 52.3 (p &lt; 0.001 for both). The study concludes that CO2 laser frenuloplasty is an effective and safe technique, offering substantial benefits in terms of reduced healing time and enhanced patient satisfaction. The significant improvements in SF-12 scores underscore the positive impact on patient quality of life, advocating for the broader application of this technique in clinical practice. Further research is warranted to explore its potential in a wider clinical context.

Effects of Irradiation of Continuous Wave Carbon Dioxide Laser on Caries Resistance of Deciduous Teeth

The objective of this st udy aimed to assess the caries-preventive potential of various CW CO2 laser parameters, and to explore the effect of the laser power density on the caries inhibition activity.Extracted human deciduous molars were irradiated with three various power dens ities, by changing the output power, the exposure time, and the spot diameter. The CO2 laser system emitted laser with 10.6µm in wavelength. All teeth were subjected to carieslike lesion form ation by 3.5 pH lactic acid for 21 days. The teeth after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.CW CO2 laser preventive treatments inhibited carieslike lesion progres sion up to 82%. This effect was improved with increasing power d ensity within the limits of the examined laser parameters.

Influence of hydrothermal ageing on CFRP single lap bonded joint pre-treated by laser texturing

In this work, the influence of hydrothermal ageing on performances of CFRP single lap bonded joints subjected to two types of pre-treatments was investigated. The first is a degreasing pre-treatment, while the second if a laser texturing pre-treatment through a CO2 laser system. The study considered the influence of an aggressive environment on geometrical deviations and mechanical performances of the bonded joints. Measurements showed that adherends were more susceptible to water uptake after ageing, allowing an increase in laminate thickness of about 2.5%. Lap shear tests were carried out and a decrease in obtained mechanical performances was observed only for the degreased specimens, confirming the effectiveness of the adopted laser texturing to reduce ageing effects. Moreover, the proposed laser texturing pre-treatment for bonding is a sustainable process too because reduces the volume of the removed material efficiently with reduced costs.

Laser Beam Polishing of PA12 Parts Manufactured by Powder Bed Fusion

PurposeMulti Jet Fusion™ (MJF) is a powder bed fusion technology that fuses material locally with infrared radiation. Fabricated parts show high mechanical strength, low porosity and good dimensional accuracy, even for challenging geometries. They do, however, have a distinctive grainy surface with a roughness of Ra > 5 μm limiting possible applications. A fairly recent technology for the smoothing and polishing of polymer surfaces is the surface re-melting by laser beam polishing (LBP). The objective of this study is to characterize the LBP-process of MJF-manufactured Nylon PA12 parts and evaluate it in relation to state-of-the-art finishing methods.MethodsPA12 samples produced using the Multi Jet Fusion™ process are laser beam polished with a 30 W CO2-laser system. A numerical model is applied in order to estimate the effects of different processing parameters and laser scanning strategies. Calculated temperature progressions are validated experimentally with thermographic measurements. The laser beam polished surfaces are subsequently characterised by surface topography, tensile strength, surface energy and hardness.ResultsA re-melting and concurrent smoothing of PA12 surfaces was demonstrated for a number of different processing strategies. The use of a line-focus resulted in the best combination of processing speed, flexibility and surface quality with a reduction in roughness of up to 91%.ConclusionLaser beam polishing is applicable to parts manufactured by Multi Jet Fusion™. Depending on the case of application, it can be preferable to conventional post-processing strategies for fusing residual powder and improving tribological properties.

Improvement of Supercapacitor Performance of In Situ Doped Laser-Induced Multilayer Graphene via NiO.

Herein, we have reported a novel strategy for improving the electrochemical performance of laser-induced graphene (LIG) supercapacitors (SCs). The LIG was prepared using a CO2 laser system. The polyimide polymer was the source material for the fabrication of the LIG. The doping process was performed in situ using the CO2 laser, which works as a rapid thermal treatment to combine graphene and NiO particles. NiO was used to improve the capacitance of graphene by combining an electric double-layer capacitor (EDLC) with the pseudo-capacitance effect. The high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy showed that the structure of the LIG is multilayered and waved. The HRTEM image proves the distribution of NiO fine particles with sizes of 5-10 nm into the graphene layers. The electrochemical performance of the as-prepared LIG was tested. The effect of the combination of the two materials (oxide and carbon) was investigated at different concentrations. The LIG showed a specific capacitance of 69 Fg-1, which increased up to 174 Fg-1 for the NiO-doped LIG. The stability investigations showed that the electrodes were very stable for more than 1000 cycles. This current study establishes an innovative method to improve the electrochemical properties of LIG.

Clinical Evaluation and Experience in Treatments Performed with Fractional CO2 Laser on Latin American Skin: An Observational Retrospective Study.

Background: The carbon dioxide (CO2) laser is an ablative system that evaporates, remodels, and coagulates tissues, becoming therefore a gold standard piece of equipment for the treatment of dermatological pathologies and esthetic imperfections. Objective: To evaluate the efficacy and safety of CO2 laser treatments in different patients' skin pathologies. Methods: A total of 705 patients with an age range between 18 and 70 years, with phototypes on the Fitzpatrick scale III, IV, V, and VI, were enrolled from October 2021 to May 2022, and were treated using the CO2 laser system. Results: Ninety-six patients were treated with fractional CO2 laser, used for skin rejuvenation and stretch marks. One patient presented reactivation of herpes simplex, 10 postinflammatory hyperpigmentation that resolved after 3 months with depigmenting agents, 6 with persistent erythema. A total of 13 patients with rhinophyma were treated, and no complications were observed; a total of 64 patients with wrinkles were treated. They improved in 6 months. A total of 340 patients were treated for seborrheic keratosis, papulosa nigra dermatosis, fibropapillomas, sebaceous hyperplasias, verruca vulgaris, and condylomata acuminata. One patient presented with a complication hypopigmented macule. A total of 136 patients underwent treatment for laser ablation of intradermal nevi and verrucous epidermal nevi, without complications. A total of 56 patients were treated with keloids and hypertrophic scars. One patient presented with ulceration of a keloid that resolved with the application of clostridiopeptidase A and chloramphenicol after 2 weeks. Conclusions: The use of the CO2 laser in any phototype and race, which are factors with a high incidence in Latin America, provides a safe and effective result for different dermatological pathologies.

Ex Vivo Human Histology Fractional Treatment with a New CO2 Scanner: A Potential Application on Deep Scarring.

Background and Objectives: For many years, fully ablative laser treatments, particularly those performed with a carbon dioxide (CO2) laser, were regarded as the gold standard for resurfacing. This study's goal is to assess the depth that can be reached by a new CO2 scanner system, through a skin model with greater dermal thickness, to use in the treatment of deep scarring. Materials and Methods: Male human skin tissue was laser-treated using a CO2 fractional laser and a new scanning system, and all samples were fixed in 10% neutral buffered formalin, dehydrated using a series of crescent alcohol, embedded in paraffin, sectioned in series (4-5 µm thick), stained with haematoxylin and eosin (H&E), and then analysed under an optical microscope. Results: From the epidermis through the underlying papillary and reticular dermis to various depths of the dermis, microablation columns of damage and coagulated microcolumns of collagen were observed. The reticular dermis was fully penetrated up to 6 mm at higher energy levels (210 mJ/DOT), resulting in deeper tissue injury. Although the laser might penetrate further, the skin stops there, leaving just the fat and muscular tissue. Conclusions: The deep layers of the dermis can be penetrated by the CO2 laser system throughout the entire dermal thickness when using the new scanning system, suggesting that this laser's potential impact, at the selected settings, covers all skin targets required to perform superficial or deep treatments on any dermatological issue. Finally, patients who have problems, such as morbid scar-deep complications, which affect their quality of life, are more likely to profit from this innovative technique.

Short-pulse CO2 laser with long pre-pulse using double-longitudinal-discharge-tube system

A CO2 laser with a double-longitudinal-discharge-tube system produced a short laser pulse with a long pre-pulse. The CO2 laser was constituted of two longitudinal discharge tubes with an inner diameter of 16 mm and a length of 60 cm, an optical resonator, two fast, high-voltage pulsed power supplies and a pulse generator. The discharge tube for generating the long pulse was discharged first, and then the discharge tube for generating the short pulse was discharged. The CO2 laser system combined a long laser pulse with a pulse width of 11.7 μs (FWHM) and a pulse length, from the start to the end of the pulse, of 26.9 μs and a short laser pulse with a pulse width of 224 ns (FWHM). In the discharge interval of about 40 μs, a short laser pulse with a long pre-pulse was generated. In the discharge interval of 100 μs or more, a long pulse preceded a short pulse. The peak intensity and pulse width of the short pulse part depended on the discharge interval because the short pulse part was affected by the discharge in the discharge tube for generating the long pulse.

CO2 Surgical Laser for Treatment of Stress Urinary Incontinence in Women: A Randomized Controlled Trial

ABSTRACT The common condition of stress urinary incontinence (SUI) has a reported prevalence of 10% to 39% in adult women in most studies. Although treatment of SUI via surgical means is an option, factors such as adverse effects of surgery and mesh-related risks lead many to seek alternative options. In overweight and obese patients, lifestyle changes for improving SUI symptoms entail mainly weight loss. Although pelvic floor muscle training (PFMT) can lead to improvements, further treatment is often necessary. Because of this, interest is high for developing effective nonsurgical treatments for SUI. One such possible treatment is vaginal laser therapy, which has been used as treatment for various vaginal conditions. The authors therefore carried out a randomized controlled trial (RCT) comparing CO2 laser with sham treatment for SUI. This multicenter, participant-blinded, sham-controlled, parallel-group, superiority RCT involved participants from 2 hospitals in Southeast Melbourne in the outpatient setting. Patients aged 18 to 80 years experiencing symptomatic and objective SUI and seeking conservative management participated. Women with prior surgery for SUI were excluded. A positive cough stress test with a comfortably full bladder and uroflow was used to determine objective SUI. Participants lacking positive cough stress test were still eligible for study inclusion with a positive pad weight test in the absence of urgency incontinence symptoms. Intervention took place using FemTouch delivery system in conjunction with the AcuScan 120 Microscanner and the AcuPulse CO2 laser system for fractional treatment. Laser energy was delivered via a standard foot pedal in a fractional manner. The sham treatment used identical methods and settings but used an inactive pedal, which only made mechanical clicks and no electronic beeps. A total of 3 treatments were administered to participants, 4 weeks apart, with incrementally greater density settings. The primary outcome of the study was subjective SUI (defined as positive answers to the inquiries: “Do you leak when you cough or sneeze?” or “Do you leak when physically active/exercising?”). Secondary outcomes were assessed via the Patient Global Impression of Improvement, and International Consultation on Incontinence Questionnaire–urinary incontinence change, International Consultation on Incontinence Questionnaire-overactive bladder, the Pelvic Organ Prolapse/Urinary Incontinence Sexual Function Questionnaire, the Incontinence Impact Questionnaire–Short Form, and EQ-5D scores. In addition, adverse events (such as pain during the procedure as measured on a visual analog scale) and objective SUI were recorded. A sample size of 101 was chosen to provide 80% power to detect differences between groups for the primary outcome (even assuming a 10% rate of attrition). A total of 97 participants ultimately were treated. Randomization of participants occurred with equal probability to sham treatment or the CO2 laser using a computer-generated random sequence, which allocated participants to blocks of 4, 6, and 8. Unblinding of participants to their allocation occurred following the 3-month review. Participants had a mean age of 53 years and a mean body mass index of 26.1 kg/m2, and 90% were vaginally parous. Most participants had attempted PFMT either independently or under supervision. No detectable difference was found between the sham and active treatment arm in the primary outcome of leak with laughter or cough. Furthermore, there were no significant differences between groups with regard to any of the secondary, patient-reported outcomes of questionnaires. The authors tested the reliability of their masking by assessing whether patients could identify their allocation group. Between the 2 groups, 17 (54%) of the sham group and 15 (63%) of the active treatment group believed they received sham treatment. Adverse events were rare in both groups, with similar visual analog pain scores during treatment and only rare vaginal bleeding and urgency incontinence in both groups. Strengths of this study are several and include its blinded design and randomization methods. The primary outcome was focused on patient-reported outcomes. Responsive and validated questionnaires were utilized for assessment of secondary outcomes. Study limitations include a lack of blinding for investigators, which could have introduced an element of detection bias for SUI. In conclusion, no benefit was shown for 3 treatment sessions of the CO2 vaginal laser when compared with sham therapy. Additional trials with various laser modalities are necessary to determine whether this may produce varying results. Women considering CO2 vaginal laser therapy for SUI should be made aware of the lack of consistent high-quality evidence in support of this treatment.

Effects of Carrier Heating on Raman Susceptibility of Weakly-Polar Semiconductor Magneto-Plasmas

In this paper, we develop a mathematical model to study the effects of carrier heating induced by a laser beam on Raman susceptibility of weakly-polar semiconductor magneto-plasmas. Using coupled mode approach, we obtain expressions for the real and imaginary parts of Raman susceptibility (Re⁡( χ_R),Im⁡( χ_R)) under hydrodynamic and rotating-wave approximations. In order to validate the results, we perform numerical analysis for n-InSb crystal - CO2 laser system. We observed change of sign of Re⁡( χ_R) as well as Im⁡( χ_R) around resonances. The carrier heating induced by the intense laser beam modifies the momentum transfer collision frequency of plasma carriers and consequently the Raman susceptibility of the semiconductor magneto-plasma, which subsequently enhances Re⁡( χ_R) and Im⁡( χ_R), (ii) shifts the enhanced Re⁡( χ_R) and Im⁡( χ_R) towards smaller values of applied magnetic field, and (iii) broadens the applied magnetic field regime at which change of sign of Re⁡( χ_R) and Im⁡( χ_R) are observed. The analysis leads to better understanding of Raman nonlinearity of semiconductor plasma and suggests an idea of development of Raman nonlinearity based optoelectronic devices. HIGHLIGHTS Effects of carrier heating on the real and imaginary parts of Raman susceptibility of weakly-polar semiconductor magneto-plasmas are investigated We observed alteration of sign of real and imaginary parts of Raman susceptibility around resonances Carrier heating induced by the intense laser beam: Enhances real and imaginary parts of Raman susceptibility, Shifts the enhanced real and imaginary parts of Raman susceptibility towards smaller values of applied magnetic field, and Broadens the applied magnetic field regime at which sign alteration of real and imaginary parts of Raman susceptibility are observed. GRAPHICAL ABSTRACT

Design, Construction and Characterization of Sealed Tube Medium Power CO2 Laser System

A low-cost medium-power carbon dioxide (CO2) laser system is designed, constructed, and characterized to produce coherent, monochromatic laser radiation in the infrared region. The laser cavity is simulated and designed by using ZEMAX optic studio. A switch-mode high-tension pump source is designed and constructed using a flyback transformer and simulated using NI Multisim to study the voltage behavior at different node points. A prototype cooling system/chiller is designed and built using thermo-electric coolers (TEC) to remove the excess heat produced during laser action. Various parameters, such as pumping mechanism, chiller stability, efficiency, output power, and current at different applied voltages, are studied. The chiller efficiency at different output powers of the laser is analyzed, which clearly shows that the chiller’s cooling rate is good enough to compensate for the heat generated by the laser system. The center wavelength of the carbon dioxide laser is 10.6 μm with an FWHM of 1.2 nm simulated in the ZEMAX optic studio. The output beam penetration through salt rock (NaCl), wood, and acrylic sheet (PMMA) at various output powers is analyzed to measure the penetration depth rate of the CO2 laser.

Investigation of optimal energy or density of a fractional CO2 laser system in the treatment of stable non-segmental vitiligo

BackgroundFractional carbon dioxide (CO2) laser has been considered to be an add-on to conventional treatments of vitiligo. Objective: This study aimed to evaluate the optimal energy and density of the fractional CO2 laser system in stable non-segmental vitiligo (NSV) patients. Method: 48 patients were treated with fractional CO2 laser and sequential phototherapies of narrowband ultraviolet B (NB-UVB), after the CO2 laser treatment, a compound betamethasone solution was topically applied. For the fractional CO2 laser, coverages of 8% and 12.6% were set as low density (Ld) and high density (Hd), and energies of 60 mJ and 80 mJ were set as low energy (Le) and high energy (He), respectively. The patients were randomly assigned to Group A (HeHd), Group B (HeLd) or Group C (LeLd). Results: Either after 3 or 6 months of enrollment, the efficacy of Group C was better than Group B (p < 0.05). No difference was seen between Group A and Group B or Group A and Group C (p > 0.05). More patients complained higher pain score in Group A as compared with Group C (p < 0.05). Conclusion: The optimal parameters of the fractional CO2 laser were energy at 60 mJ and density at 8%.

Compact Radio Frequency Discharge-Pumped Slab CO Laser System with a Zinc Germanium Phosphide (ZnGeP2) Sum-Frequency Generator for Remote Sensing of the Atmosphere.

Based on our experimental study of spectral characteristics of an improved compact CO laser system, the prospects of using such a laser system for solving urgent problems of atmospheric sounding were demonstrated. An increase in the number of laser lines due to intracavity generation of the second harmonic and sum-frequencies in a nonlinear zinc germanium phosphide (ZnGeP2) crystal enriches capabilities of the laser. It was shown that such a CO laser system with frequency conversion in ZnGeP2 crystal can be used for detection and measuring concentration of at least 14 minor natural and pollution gases components of the atmosphere. The advantages and disadvantages of various laser operation modes, and the prospects for using its radiation for atmospheric remote sensing in various spectral ranges are discussed.

Hot Carrier Effects on Real and Imaginary Parts of Brillouin Susceptibilities of Magnetoactive Doped III-V Semiconductors (Applied to N-type Doped InSb)

An analytical investigation is made of hot carrier effects on real and imaginary parts of Brillouin susceptibility ( ) of magnetoactive doped III-V semiconductors. Coupled mode approach is used to obtain expressions for . Numerical calculations are made for n-InSb crystal −CO2 laser system. Efforts are made to obtain enhanced values of and change of their sign under appropriate selection of external magnetic field (B0) and doping concentration (n0). The hot carrier effects of intense laser radiation modifies the momentum transfer collision frequency of carriers and consequently the nonlinearity of the medium, which in turn (i) further enhances , (ii) shifts the enhanced towards smaller values of B0, and (iii) widens the range of B0 at which change of sign of occurs. The change of sign of enhanced of magnetoactive doped III-V semiconductors, validates the possibility of chosen Brillouin medium as a potential candidate material for the fabrication of stimulated Brillouin scattering dependent widely tunable and efficient optoelectronic devices such as optical switches and frequency converters.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Hot carrier effects of intense laser radiation&#x0D; &#x0D; enhances real and imaginary parts of Brillouin susceptibility,&#x0D; shifts the enhanced real and imaginary parts of Brillouin susceptibility towards smaller values of magnetostatic field,&#x0D; widens the range of magnetostatic field at which change of sign of real and imaginary parts of Brillouin susceptibility occurs&#x0D; &#x0D; &#x0D; Analysis offer three achievable resonance conditions at which significant enhancement as well as change of sign of real and imaginary parts of Brillouin susceptibility are obtained&#x0D; Analysis establishes the technological potentiality of III-V semiconductors as hosts for fabrication of SBS based widely tunable and efficient optoelectronic devices&#x0D; &#x0D; GRAPHICAL ABSTRACT&#x0D;

Synergistic Sequential Emission of Fractional 10.600 and 1540 nm Lasers for Skin Resurfacing: An Ex Vivo Histological Evaluation.

Background: Fractional ablative and non-ablative lasers are useful treatments for skin rejuvenation. A procedure that provides the sequential application of fractional ablative followed by non-ablative laser treatment may reduce patients’ downtime and deliver better cosmetic results than with either laser alone. Objective: The purpose of the current study was to demonstrate the ameliorative and therapeutic effects in skin remodeling of the synergistic use of the two laser wavelengths (fractional ablative CO2 and non-ablative 1540 nm) with three different types of pulse shapes, S-Pulse (SP), D-Pulse (DP) and H-Pulse (HP), through which the CO2 laser can emit, performing an ex vivo histological evaluation. Methods: In this prospective study, ex vivo sheep inner thigh skin was chosen due to its similarity to human skin tissue, and a histological evaluation was performed. Three irradiation conditions, using all of the three CO2 pulse shapes (alone or averaged), were investigated: (1) 10.600 nm alone, the sequential irradiation of the two wavelengths in the same perfectly controlled energy pulses (DOT) for the entire scan area; ((2) 10.600 nm followed immediately by 1540 nm; and (3) 1540 nm followed immediately by 10.600 nm). Results: When comparing ablative to sequential irradiations, the synergy of the two wavelengths did not alter the typical ablative pulse shape of the 10.600 nm laser alone. With the same CO2 pulse shape, the lesion depth did not vary with the synergy of the two wavelengths, while thermal lesion width increased compared to CO2 alone. The ablation rate was achieved, while the total thermal lesion coverage in the scanning area of CO2 − 1540 lasers was greater than when using CO2 alone and then the other sequential irradiation. Conclusions: This study provides important preclinical data for new and early uses of the novel 10.600/1540 nm dual-wavelength non-ablative fractional laser. The synergy of the two wavelengths enhanced all the benefits already available when using CO2 laser systems both in terms of tone strengthening, thanks to a greater shrinking effect, and in terms of stimulation and collagen remodeling thanks to a greater volumetric thermal effect.