Search

Background 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. Aims To evaluate the efficacy and safety of 1540-nm fractional erbium glass laser in the treatment of AGA. Patients/methods 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. Results Forty-seven out of 51 patients completed the study. After 5 months of laser treatment, the density of hair and hair thickness was significantly increased in both males and females (P value .001). Conclusion 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.

Ultralow phase-noise mode-locked lasers are crucial for real-world applications. We present two accomplishments: (1) short-term FF CEP stabilization of a SESAM mode-locked Er:Yb:glass laser at 1.55 um with timing jitter below 3 as (1-3 MHz) and (2) a hybrid solution adding a FB technique addressing slowly varying sources of interference to the FF system that demonstrates 75 hours of stabilization with a minimally detrimental effect amounting to a timing jitter of 11 as.

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory contains a 192-beam 4.2 MJ neodymium glass laser (around 1053 nm or 1w) that is frequency converted to 351nm light or 3w. It has been designed to support the study of Inertial Confinement Fusion (ICF) and High Energy Density Physics (HEDP). The NIF Precision Diagnostic System (PDS) was reactivated and new diagnostic packages were designed and fielded that offer a more comprehensive suite of high-resolution measurements. The current NIF laser performance will be presented as well as the preliminary results obtained with the various laser experimental campaigns using the new diagnostic tool suites.

We report the first (to the best of our knowledge) high-power, low-coherence Nd:glass laser delivering kilojoule pulses with a coherent time of 249 fs and a bandwidth of 13 nm, achieving the 63%-efficiency second-harmonic conversion of the large-aperture low-coherence pulse and good beam smoothing effect. It provides a new type of laser driver for laser plasma interaction and high energy density physics research.

The aim of this work was to investigate the utilization of Co:Spinel as saturable absorber for eye-safe Er:YAG laser generating at 1645 nm wavelength. Co:Spinel (Co:MgAl 2 O 4 , Co:MALO) absorber is used to Q-switching for laser systems generating about 1.5 μm wavelength, for example for Er:glass laser. Due to lower radiation absorption above the 1.55 μm wavelength of Co:spinel, the another passive absorbers were investigated, e.g. U:SrF 2 [1], Co:GSGG [2], and Cr:ZnSe [3]. However, the advantage of Co:Spinel is its high damage threshold and therefore, the research of its utilization would be prolonged, especially for 1.6 μm Er:YAG laser.

The possibility of using bursts of microsecond pulses of an Yb,Er : glass laser (λ = 1.54 μm) for cataract destruction was investigated experimentally in vitro for the first time. The energy in a laser pulse was limited from below by the eye lens destruction threshold and from above by the radiation resistance of the input end face of the radiation-supplying fibre. The energy of a burst consisting of three microsecond laser pulses, separated by time intervals of 850 μs, was 255 ± 15 mJ, and the burst repetition rate was 15 Hz. The hydroacoustic signal, generated after each burst pulse in the water around the lens, contained two components. The first occurred immediately after the laser pulse transmission, and the second was delayed by 250 to 350 μs. The amplitude of the second component of the hydroacoustic signal exceeded the amplitude of the first component and was maximum (50.0 ± 8.0 MPa) for the signal induced by the second pulse in the burst. The efficiency of cataract destruction by microsecond-pulse bursts generated by an Yb,Er : glass laser was found to depend on the lens nucleus density, to exceed significantly the efficiency of cataract destruction by single microsecond pulses of this laser, and to be comparable with the efficiency of eye lens destruction by a 1.44-μm Nd : YAG laser.

Bicolour illumination by 1.54/0.77 μm 20 ns pulsed Er:glass laser beams leads to enhancement of the initial effective piezoelectric coefficients for Ag0.5Pb1.75GeS4 and Ag0.5Pb1.75GeS3Se crystals in a different way. The contribution of the photo-thermal effect did not exceed 4 %. The relaxation processes last up to 50 ms and are completely reversible with respect to piezoelectricity. The effect is reproducible even after more than 100 cycles of the photoinduced laser treatment. The use only of the mopnochromatic wavelengths 1.54 μm (0.77 μm) did not show sufficient enhancement of the effect, and the changes were commensurable with the background. The efficiency of the laser photoinduced treatment depends on the angle between the bicolour photoinducing beams, ratio of their intensities and their relaxation behaviour is a slightly different. However, at at 50 ms the photoinduced piezoelectric signal disappears for the both samples. It is crucial that laser polarizations of the photoinducing beams do not play important role.

The active delivery of photodynamic agent (aqueous solution of methylene blue) under a nail plate is discussed. The delivery was implemented by microperforating the nail plate using Er:YLF laser radiation and stimulating hydrodynamic processes in drug droplet on the nail surface under the action of Yb,Er:Glass laser pulses. Optimal pulse energy of Yb,Er:Glass laser radiation for effective active delivery of the photodynamic agent is determined.

We report on the development of a compact side diode pumped eye-safe A/O Q-switched Yb:Er:glass laser at repetition rates as high as 40 Hz. The laser generates 1.3 mJ / 45 ns pulses with the beam divergence 4.5 mrad without collimating system. The laser diodes and laser rod are conductive thermoelectrically cooled. The high repetition rate operation with good beam quality is demonstrated.

An eye-safe Yb:Er:glass laser with a repetition rate 10 Hz was developed. The device was a diode pumped Yb:Er:glass laser Q-switched by an acousto-optic gate producing 12 mJ energy and 20 ns FHWH duration pulses of 1.54 um radiation. The laser rod and laser diodes are cooled by a thermoelectric module. The laser head dimension were 180×80×80 mm3.

Introduction: Non-ablative fractional erbium-doped glass 1540 nm and fractional ablative 10600 nm carbon dioxide lasers are regarded as effective modalities for treating acne atrophic scars. In this study, we aimed to compare the effectiveness of fractional CO2 laser and fractional nonablative 1540 nm erbium doped glass laser in treating post acne atrophic scars in Egyptian patients. Methods: Fifty-eight patients complaining of moderate and severe acne atrophic scars were randomly divided into 2 groups of 29 patients each. Both groups were subjected to 4 treatment sessions with 3 weeks interval and were followed up for 3 months. In group A, enrolled patient sreceived C2 laser, while in group B, patients were treated with 1540 nm erbium glass fractional laser. Results: Clinical assessment revealed that the mean grades of progress and improvement were higher with fractional 10600 nm CO2 laser but with non-significant difference between both treatments (P = 0.1). The overall patients' satisfaction with both lasers were not significantly different (P = 0.44). Conclusion: Both fractional ablative CO2 and fractional non-ablative erbium glass lasers are good modalities for treating acne scars with a high efficacy and safety profile and good patient satisfaction. The fractional ablative laser showed higher efficacy while non-ablative laser offered less pain and shorter downtime.

BACKGROUND Treatment of cutaneous leishmaniasis remains a challenge; new physical treatment modalities including laser systems are of interest in the treatment of localized lesions. METHOD Fourteen patients (10 females) with 20 lesions of Old World cutaneous leishmaniasis underwent weekly treatments of 1540 nm erbium glass fractional laser (Palomar) using 10 mm spot size hand piece in four passes of 50-70 mJ/cm2 fluence and 10 ms pulse duration. RESULTS Twelve lesions were available for assessment: six (50%) improved at 6 weeks and eleven lesions (91.7%) at 12 weeks. There were no recurrences at 6- and 12-month follow-ups. CONCLUSION Erbium glass fractional laser may be an alternative treatment for localized cases of Old World cutaneous leishmaniasis.

We demonstrate a laser diode end-pumped helium gas-cooled multislab Nd:glass laser amplifier. The design and thermal management of the proposed laser amplifier are discussed. The thermally induced wavefront aberration of the slabs was also measured and compared with simulation results. A small-signal single-pass longitudinal gain of 1.8 was measured with a pump energy of 7.3 J. With an injected seed energy of 0.6 mJ, the output energy from the amplifier reached 0.5 J at 0.2 Hz and 0.43 J at 0.5 Hz in a multipass extraction geometry, thus demonstrating the feasibility of diode-pumped, high-energy lasers with direct gas cooling.

The 10PW OPCPA/glass laser under construction for ELI-Beamlines will exhibit output pulses delivered every minute with an energy of 1.5kJ within 150fs duration. We will show results of the sub-sections as well as output performances.

To evaluate the use of a pinpoint irradiation technique followed by nonablative fractional technique in treatment of traumatic scars. Thirteen patients with traumatic sacrs were treated with pinpoint technique of CO2 laser using traditional headpiece activating laser at a frequency (50 Hz) to deliver pulsed mode with power of 1 W using the focusing technique followed by 3-5 passes of the nonablative 1540 nm fractional Er:glass laser. An independent physician evaluator assessed the treatment outcomes using Vancouver scar scale (VSS) and 5-point grading scale (grade 0, no improvement; grade 1, 1-25%; grade 2, 26-50%; grade 3, 51-75%; grade 4, 76-100% improvement). After the final treatment, average percentage changes of VSS were 41.5%. Improvement was evident in terms of vascularity, pigmentation, and height, while insignificant in terms of Pliability. Based on physician's global assessment, mean grade of 2.5 was achieved. Patient's subjective satisfaction scores paralleled the physician's objective evaluation. Pinpoint irradiation technique by CO2 laser followed by nonablative fractional laser is a safe and effective modality in treatment of scars.

Light-based technologies are strongly supported by various glass materials in general. This article focuses on glasses containing rare-earth elements, doped fibers, as well as their photonic functions such as optical amplifications in fiber telecommunication. Scientific progress and applications of rare-earth spectroscopy and technologies of doped glasses and fibers in recent 60 years have been more than dramatic. Development of various laser diodes has been strongly linked with realization of novel devices of rare-earth-doped glasses. In addition to many milestones listed in the resolution of International Year of Light, we should notice that 2015 is also the 50th anniversary of the erbium-doped glass laser, which is later transformed into the optical fiber amplifier, the enabler of today's information society.

Introduction: Despite its clinical features of multiple, confluent, small, whitish, smooth, and clear-demarcate papules on the neck and back, the pathogenesis of white fibrous papulosis of the neck (WFPN) is still unknown. The lesions increase progressively and do not regress over time. However, no effective treatment has yet been identified.Case Report: We reported the successful results of a female patient receiving efficacious treatment for her extensive lesions of WFPN with nonablative fractional photothermolysis laser (Fractionated 1550-Erbium Glass laser).Conclusion: This photothermolysis laser could then be suggestive as the therapeutic option for WFPN.

Acne is a chronic disease of the pilosebaceous units, presenting as inflammatory or noninflammatory lesions, affecting primarily the face but also the back and chest. The mainstay of treatment remains topical retinoids, benzoyl peroxide, azelaic acid, antibiotics, and isotretinoin, many of which result in poor compliance, lack of durable remission, and incur adverse effects. The use of lasers to treat acne is continuously increasing because of their minimal complications, limited number of office-based treatments required, potential benefits of simultaneously treating acne scarring, and the rapid onset of results. The 1450 nm diode laser, 585- and 595-nm pulsed dye lasers (PDLs), near infrared diode lasers, 1320 nm Nd:YAG laser, 532 nm potassium titanyl phosphate laser, 1064 nm long-pulsed Nd:YAG laser, 1540 nm Erbium (Er):Glass Laser, and the 1550 nm Er:Glass fractional laser are among the most common lasers used to treat acne and acne scarring. These lasers target the underlying causes of acne including the colonization of Priopionibacterium acnes, high levels of sebum production, altered keratinization, inflammation, and bacterial colonization of hair follicles on the face, neck, and back. We review the efficacy and side effect profiles of various lasers used to treat acne.

The results of in vitro pilot study of anterior lens capsule destruction by submicrosecond pulses of Yb,Er:Glass laser as well as results of 2% agar gel damage threshold investigation are presented. It was established that the local destruction of anterior lens capsule is possible without any ruptures at energy densities up to 25 J/cm2 when exposed to 30 laser pulses, delivered via 200 μm optical quartz fiber. It was found that 2% agar gel damage threshold determined as minimal value of laser energy density required for appearance of the visually identifiable damage of agar gel decreases with the increase in the number of laser pulses. The 2% agar gel damage threshold on the air for a single laser pulse impact was about 2.3-3.3 J/cm2, for 5 pulses impact – about 1.8-2.5 J/cm2 and for 10 pulses impact – about 1.6-2.4 J/cm2.

A new laser facility with 30kJ/ns/3ω(8 beams) output energy has begun operation with good performance. Another single laser prototype pushes 1ω output energy to 17.5kJ/21ns in 350mm×350mm aperture with four-pass main amplifier architecture.

Nd:Glass lasers enable high energy, ultra high intensity pulses with 10PW peak power. Lasers technology with active cooling provides orders of magnitudes improved over previous shots rates will be discussed.

BACKGROUND Novel and promising results in acne treatment with infrared lasers have been reported. The 1,550-nm erbium glass laser is one of the infrared lasers that may be useful in the treatment of acne. OBJECTIVE The aim of this study was to evaluate the efficacy of an erbium glass laser in treatment of active acne and to study the effect of this type of laser on sebaceous glands. PATIENTS AND METHODS Twenty-four patients with active acne lesions were treated using 1,550-nm (30-40 mJ) fractional erbium glass laser. Every patient received 4 sessions with a 2-week interval. Follow-up was done every 3 months for 1 year. The image analyzer computer system was used to measure the sebaceous gland size. RESULTS A significant reduction (p < .0001) in the mean count of lesions was observed after treatment and in the follow-up period. A significant reduction in the size of sebaceous glands was also evident after laser treatment. CONCLUSION Treatment of active acne with the 1,550-nm erbium glass laser is effective. Papules, pustules, and nodules all respond well to therapy. The sebaceous gland size decreased significantly, which accounts for the long remission period.

Aluminum flyer with thickness of 50μm and diameter of 1mm had been driven successfully by high-power Nd:Glass laser system. Average speed of the flyer was detected by piezoelectric Polyvinylidene Fluoride (PVDF) transducer, which reached 6.67km/s. Extent of damage to protective materials of spacecrafts was studied after they were hit by the driven aluminum flyer. The protective materials of spacecraft were damaged structurally in our experiment, and the damage observed under the microscope was also shown. It could be seen that the flyer knocked a tiny hole with diameter of about 1mm in the protective cellular board, and there were traces of impact damage around the tiny hole, which indicated that protective materials of spacecrafts would be damaged structurally when they were hit by flyer with size of 1mm. At the same time, the hyperspeed flyer still had good integrity and flatness. The results showed that laser-shockwave-driven hyperspeed flyer technology could be used as an effective experiment means to simulate high-speed space particles, which made it feasible to establish a set of simulation device of laser-shockwave-driven hyperspeed flyer for the research of protective materials of spacecrafts on the ground.

In this paper, the characteristics of ablation processing of the eagle glass by pico-second laser are investigated. The laser ablation is used to process micro forms on materials. The ablation causes little thermal effect and little burr on the surface of eagle glass. In order to examine the characteristics of panic cracks, experiments are conducted under various cutting conditions such as a frequency of 600 kHz, laser powers, scan speeds and number of scan(NS). To minimize the panic cracks, the specimens are heated at 30℃, 45℃, and 60℃ for ten minutes respectively and then they are broken by hands. Laser powers, NS and scan speeds have an effect on glass cutting results. The ablation depths increase with an increase in the laser power and NS whereas the panic cracks decrease with an increase in scan speed. The high temperature on processed specimens reduces the panic cracks and makes good results of laser cutting. The optimal condition for eagle glass laser cutting is found to be at 30 W of laser power, 3 mm/s of scan speed and 500 of NS, respectively.

Introduction: Melasma is a commonly acquired hypermelanosis and a common dermatologic skin disease that occurs on sun-exposed areas of face. Aims: To assess the efficacy and safety of non-ablative 1,550 nm Erbium glass fractional laser therapy and compare results with those obtained with chemical peeling. Materials and Methods: We selected 30 patients of melasma aged between 20 years and 50 years for the study. The patients were divided into two groups of 15 patients each. Group I patients were subjected to four sessions of 1,550 nm Erbium glass non-ablative fractional laser at 3 weeks interval. In group II patients, four sessions of chemical peeling with 70% glycolic acid was performed. Results: After 12 weeks of treatment, percentage reduction in Melasma Area and Severity Index (MASI) score was seen in 62.9% in the laser group and 58.7% in the peels group. Conclusion: It was observed that 1,550 nm fractional laser is as effective as 70% glycolic acid peel in reducing MASI score in patients with melasma.

Transparent glass-ceramics based on Co2+:ZnO nanocrystals are synthesized in cobalt-doped glasses of the K 2 O-ZnO-Al 2 O 3 -SiO 2 system. Passive Q-switching of an Er, Yb:glass laser with 0.37 mJ/100 ns pulses at ∼1.54 μm is realized.

Temperature distribution is the key factor affecting the bonding quality in the glass/glass laser bonding process. In this work, the finite element method was used to establish three-dimensional (3D) numerical analysis model of the temperature field during bonding. Based on the result of the finite element analysis, the crucial parameters and their influences on the temperature distribution were discussed. In order to predetermine the necessary process parameter values for bonding, a nonlinear multiparameter fitting formula was established to predict the maximum temperature. The fitting model was validated experimentally by recording the maximum temperature during laser bonding via an infrared thermal imager.

The liquid confinement medium (LCM) and the free confinement medium (FCM) made by ourselves were used as confinement overlays of laser shock processing (LSP) respectively, stainless steel 304 was shocked by Nd:Glass laser. The parameters of LSP are the wavelength of 1.06μm, the pulse duration of 20ns, and output energy of 35~40J. The laser was focused on a spot of Ф5mm. Firstly, the profiles of shocked regions of samples were measured by Taylor Hobson admeasuring apparatus, in which two different confinement mediums are used by LSP. Secondly, the ruinous behavior of the free confinement overlays induced by laser shock wave is observed and analyzed. Analyzed and compared with the experiments results, it is discovered that the effects of LSP are different with using different confinement mediums.

Objective This study aimed to compare the clinical efficacies of 1550- and 1565-nm Er:glass lasers in the treatment of periorbital wrinkles and to evaluate histological changes after treatment. Methods Twenty patients received five treatments each at 3-week intervals. The right periorbital area was exposed to the 1550-nm Er:glass laser and the left periorbital area was exposed to the 1565-nm Er:glass laser. Clinical improvement was evaluated by two blinded physicians who assessed comparative photographs using a four-point scale at baseline and 3 months after the final treatments. Skin biopsies were performed in five volunteers before treatment and at 3 months after the final treatment. Results The mean improvement scores 3 months after treatment with the 1550- and 1565-nm Er:glass lasers were 2.25 ± 0.62 and 2.28 ± 0.59 respectively. Histological examination revealed increased epidermal thickening and decreased solar elastosis 3 months after the final laser treatments. Conclusions Both 1550- and 1565-nm Er:glass lasers are safe and effective modalities in the treatment of periorbital wrinkles with no significant differences between the two lasers.

Pulse synchronisation with an accuracy of no worse than ±5 ns is demonstrated in passively Q-switched neodymium phosphate glass and Nd:YAG lasers. Two operating regimes are realised: the 'sub-threshold' regime (when the slave Nd:YAG laser does not generate a giant pulse if its passive Q switch is not irradiated by the master Nd:glass laser) and the 'above-threshold' regime (when the pulse irradiating the passive Q switch of the slave laser advances its generation).

We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:...

1623 nm Er:YAP and 1648 nm Er:YAG lasers resonantly pumped by a solid state Er:glass laser operating at 1535 nm were investigated. Laser generation was reached for Er:YAP and two Er:YAG crystals with different Er ion concentration. The maximal output energies were 20 and 45 mJ for Er:YAP and Er:YAG laser systems, respectively.

The inuence of the cavity trapped amplied luminescence (CTAL) on the threshold, power and dynamic characteristics of Er, Yb : glass lasers with end and side diode pump congurations has been studied. The CTAL loss coefcient has been evaluated using the luminescence balance equation. The inverse proportion dependence of the CTAL loss coefcient on the cavity length has been revealed. It has been shown that amplication of luminescence in the laser cavity leads to a signicant increase of the threshold pump power (»3n5 times). The Er, Yb : glass laser generation dynamics has been modelled taking into account the luminescence evolution beginning with the onset of the diode pumping pulse. Depending on the diode pumping pulse amplitude, the increase or decrease of the Er, Yb : glass laser pulse generation delay can be observed.

As compared with ablative fractional CO2 laser, ablative fractional erbium-doped yttrium aluminum garnet (Er:YAG) laser is considered to be a more suitable treatment option for photoaged skin in Asians due to the lower incidence of postinflammatory hyperpigmentation.To compare the efficacy and safety of ablative fractional Er:YAG laser (ablative fractional resurfacing [AFR]) and nonablative fractional 1550-nm Er:glass laser (non-AFR [NAFR]) in the treatment of photoaging.This was a prospective, randomized, double-blinded comparative study. In three sessions, at four-week intervals, 19 patients received Er:YAG AFR, and 15 patients received Er:glass NAFR. Pigmentation, uneven tone/erythema, wrinkles and overall features of photoaging were scored. Patient satisfaction, adverse effects and pain scores were recorded. Melanin and erythema indexes were measured.Reductions in pigmentation and uneven tone/erythema scores were significantly greater after Er:YAG AFR, while wrinkle score reduction was significantly greater after Er:glass NAFR. Physician and patient assessments for the overall features showed greater improvement in the Er:glass NAFR. Treatment-related pain or adverse events were less in the Er:YAG AFR.Both Er:YAG AFR and Er:glass NAFR are effective and safe and could be used in a complementary manner for treating photoaged Asian skin.

Purpose. Early postoperative fractional laser treatment has been used to reduce scarring in many institutions, but the most effective energy parameters have not yet been established. This study sought to determine effective parameters in the treatment of facial laceration scars.Methods. From September 2012 to September 2013, 57 patients were enrolled according to the study. To compare the low and high fluence parameters of 1,550 nm fractional erbium-glass laser treatment, we virtually divided the scar of each individual patient in half, and each half was treated with a high and low fluence setting, respectively. A total of four treatment sessions were performed at one-month intervals and clinical photographs were taken at every visit.Results. Results were assessed using the Vancouver Scar Scale (VSS) and global assessment of the two portions of each individual scar. Final evaluation revealed that the portions treated with high fluence parameter showed greater difference compared to pretreatment VSS scores and global assessment values, indicating favorable cosmetic results.Conclusion. We compared the effects of high fluence and low fluence 1,550 nm fractional erbium-glass laser treatment for facial scarring in the early postoperative period and revealed that the high fluence parameter was more effective for scar management.

Acne treatment by a mid-infrared laser may be unsatisfactory due to deeply situated acne-affected sebaceous glands which serve as its target. Skin manipulation by vacuum and contact cooling may improve laser-skin interaction, reduce pain sensation, and increase overall safety and efficacy. To evaluate the safety and efficacy of acne treatment using an integrated cooling-vacuum-assisted 1540-nm erbium:glass laser, a prospective interventional study was conducted. It included 12 patients (seven men and five women) suffering from mild-to-moderate acne vulgaris. The device utilizes a mid-infrared 1540-nm laser (Alma Lasers Ltd. Caesarea, Israel), which is integrated with combined cooling-vacuum-assisted technology. An acne lesion is initially manipulated upon contact by a vacuum-cooling-assisted tip, followed by three to four stacked laser pulses (500-600 mJ, 4 mm spot size, and frequency of 2 Hz). Patients underwent four to six treatment sessions with a 2-week interval and were followed-up 1 and 3 months after the last treatment. Clinical photographs were taken by high-resolution digital camera before and after treatment. Clinical evaluation was performed by two independent dermatologists, and results were graded on a scale of 0 (exacerbation) to 4 (76-100 % improvement). Patients' and physicians' satisfaction was also recorded. Pain perception and adverse effects were evaluated as well. All patients demonstrated a moderate to significant improvement (average score of 3.6 and 2.0 within 1 and 3 months, respectively, following last treatment session). No side effects, besides a transient erythema, were observed. Cooling-vacuum-assisted 1540-nm laser is safe and effective for the treatment of acne vulgaris.

We obtained single frequency laser pulses with enery of 1.67-J and duration of 310-ps based on the nonfocusing-pumped stimulated Brillouin scattering. A high-power Nd:glass laser system delivers 3-ns super-Gaussian-shaped pulses is used as the light-source.

Laser shock processing (LSP) is a new technology for surface strengthening holes. In this procedure, the choice of laser parameters is essential. The present paper investigates a method for optimising the laser parameters in laser shock processing of holes. Based upon this method, a series of laser shocking experiments were performed using a Q switched neodymium glass laser. The fatigue test results show that the fatigue life of a hole can be greatly increased after LSP. The average fatigue life of a laser shocked hole is 2·2 times longer than that without laser treatment.

Background:. Nonablative remodeling has recently been proposed as a new antiaging treatment with no downtime. This technique could greatly benefit the increasing numbers of patients who are looking for new and efficient techniques, with a minimum of discomfort. Materialsheading. and methods. The 1.54 μm wavelength has been proposed for this application because this wavelength is well absorbed by water yet virtually not at all by melanin, allowing deep penetration into the skin. To protect the epidermis during laser irradiation, a cooling system (+58C) uses a sapphire window (purified tetrafluoroethane circulates in a pipe around the sapphire) directly applied to the skin through which the laser pulse may be fired. Results. Several clinical trials have been published and have demonstrated that clinical improvement was correlated with data from ultrasound imaging, histology, and profilometry. A recent trial on the forehead and neck yielded additional data on elasticity measured by echorheometry. Conclusions. The 1.54 μm laser is safe and effective for remodeling in all of these published studies. Remodeling requires months to achieve its goal, and the kind of improvement that can be expected should be explained to the patient. Long-term follow-up showed that the improvement increased after each treatment and lasted for months after the final session.

A 120 TW/36 fs laser system based on Ti:sapphire chirped-pulse amplification (CPA) has been successfully established in our lab. The final four pass Ti:sapphire amplifier pumped by an energetic single-shot Nd:YAG—Nd:glass laser was designed and optimized. With 24 J/8 ns pump energy at 532 nm, 300 mJ/220 ps chirped pulse was amplified to 5.98 J in this amplifier, and a total saturated gain of ∼20 was achieved. The focused intensity of compressed beam could reach to 10 20 W/cm 2 with the M 2 of ∼2.0.

BACKGROUND AND OBJECTIVES Terawatt (TW) lasers have become commonplace since the development of the chirped-pulse amplification method using Ti:sapphire and Nd:glass laser rods. We have measured the minimum visible lesion (MVL) thresholds for porcine1The animals involved in this study were procured, maintained, and used in accordance with the Federal Animal Welfare Act and the "Guide for the Care and Use of Laboratory Animals" prepared by the Institute of Laboratory Animal Resources-National Research Council. Brooks City-Base, TX has been fully accredited by the Association for Assessment and Accreditation of Laboratory Animal Care, International (AAALAC) since 1967. (Yucatan mini-pig) skin using TW laser pulses. STUDY DESIGN/MATERIALS AND METHODS Our system produced laser pulses at 810 nm and sub-50 femtoseconds. These 1-2 TW laser pulses created multiple self-focusing (SF) filaments during propagation and were directed on the flanks of mini-pigs under anesthesia. We measured the pulse energies necessary to determine the ED(50) skin damage thresholds. RESULTS The MVL ED(50) threshold at 1 hour was 8 mJ and increased to 21 mJ after 24 hours. Histological sections were obtained after 1-hour and 24-hour readings. CONCLUSIONS The damage patterns on the skin indicated the number of filaments in the laser pulse. Many of the pulses produced only superficial damage that disappeared in 24 hours and that nearly three times the pulse energy was required to cause subdural or cellular damage. With further research, non-thermal tissue ablation using TW laser pulses could provide a viable alternative to current techniques of laser use in dermatology.

A new laser-driven flyer system is developed for use with the GEKKO/HIPER high-power glass laser system. The system employs an 8-μm three-layered flyer target and a new optical system for flyer velocity measurement, and is demonstrated to be capable of accelerating the flyer to approximately 23 km/s at 1031 J laser energy while maintaining a very flat shape. This is one of the highest flyer velocities reported to date, and shows the efficiency and utility of laser-driven flyer techniques in the study of material dynamics.

The Integration Test Bed (ITB) is a large-aperture single-beam Nd:glass laser system, built to demonstrate the key technology and performance of the laser drivers. It uses two multipass slab amplifiers. There are four passes through the main amplifier and three passes through the booster amplifier. The output beam size is 360mm by 360mm, at the level of 1% of the top fluence. The designed output energy of ITB at 1053nm is 15kJ in a 5ns flat-in-time (FIT) pulse, the third harmonic conversion efficiency is higher than 70%. The first phase of the ITB has been completed in July 2013. A series of experiments demonstrated that laser performance meets or exceeds original design requirements. It has achieved maximum energies at 1053nm of 19.6kJ at 5ns and 21.5kJ at 10ns. Based on a pair of split third harmonic generation KDP crystals, the third harmonic conversion efficiency of about 70% and 3ω mean fluences as high as 8.4 J/cm 2 have been obtained with 5ns FIT pulse.

We report what is to our best knowledge the first Kerr-lens mode-locking of a Nd:silicate glass laser. Pulses as short as 64 fs were generated. For a broadband inhomogeneously broadened laser, the formation of the soliton-like pulses requires a minimum amount of negative group velocity dispersion (GVD), and more negative GVD is needed to have stable, self-sustained mode locking.

Background. Nonablative remodeling has been recently proposed as an alternative to CO2 and Er:YAG resurfacing. Objective. To evaluate the efficacy and safety of a 1540 nm Er:glass laser with contact cooling in nonablative skin remodeling, focused on perioral and periorbital rhytides. Methods. Sixty patients (mean age 47 years), Fitzpatrick skin types I–IV were treated four times over 6-week intervals. Patients were evaluated using digital photographs, histology, ultrasound imaging, and profilometry with silicone imprints in order to quantitate the degree of clinical improvement. Results. All subjects reported subjective improvement in the quality and visual aspect of their skin. This was confirmed by a 40.2% reduction of anisotropy (P < .001) 6 weeks after the fourth treatment. Ultrasound imaging demonstrated a 17% increase of dermis thickness (P < .005). Biopsy specimens showed evidence of new collagen formation. Conclusion. This study has clearly demonstrated that irradiation with 1540 nm Er:glass laser can lead to new collagen formation, dermis thickening, reduction of anisotropy of the skin, and clinical improvements. The lack of adverse effects confirmed that this 1540 nm laser emitting in a pulsed mode coupled with an efficient cooling system is safe.

Inorganic nano-crystallites (NC) (CdO, ZnO, ZnS, ZnSe) incorporated into photopolymer matrices (7.5% by weight) were optically treated by coherent bicolor nano-second laser pulses at Er3+ glass laser lines at 1.54 and 0.77 μm. We have achieved a sufficiently good effective second-order susceptibility coefficients (up to 2.8 pm/V) at wavelengths 1.54 μm. The maximal second-order optical susceptibility was achieved for NC sizes equal to about 30 nm. Relaxation processes are studied.

The properties of optical parametric amplifiers are well suited to their use as chirped pulse amplifiers in short pulse high-power systems. In addition to the possibility of very simple designs to extend to shorter pulses the limits of millijoule systems, they can be used for very high-intensity applications when used in conjunction with narrow-bandwidth high-energy lasers. Powers exceeding 10 PW and focused intensities more than 1023 W/cm2 are predicted using existing glass laser technology.

A new compact and low-power-consuming cw intracavity laser absorption spectroscopy (ICLAS) spectrometer with a broad tunability near 1.06 μm has been developed. This ICLAS spectrometer uses a thin plate of Nd:glass as the amplification medium and allows pumping by a laser diode. The absorption spectrum of nitrous oxide 14 N 2 16 O has been recorded near 9400 cm−1 with this new ICLAS apparatus. It reveals an extremely weak absorption band centred at 9398.848 cm−1. The corresponding upper term value, vibrational assignment and Bv rotational constant, as well as the band intensity, are quantitatively discussed in the frame of the vibrational cluster model. The observed atmospheric spectrum in the region is assigned to H 2 16 O and discussed.

A cloud ceilometer using a solid-state laser was developed by the French meteorological office in association with Sfim ODS. The transmitter is an eye-safe erbium-glass laser operating at 1.54 μm. Cloud-base heights are deduced from extinction profiles calculated by the Klett lidar inversion algorithm. The inversion process is carried out in successive steps—first the high isolated clouds and then the lower part of the atmosphere. For each step a clear-air extinction boundary value is chosen. Temporal and statistical comparisons of the erbium-glass laser ceilometer with conventional ceilometers of the French network using flash-lamp or GaAs laser-diode transmitters are presented. Under nonprecipitating conditions, cloud-base height comparisons show very similar results; but when precipitation is present, the erbium-glass laser yields a significant performance improvement over the laser-diode ceilometer.