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Over the past six decades, dye laser technology has improved substantially. The usage of solid matrices containing laser dyes is becoming more and more popular as a viable substitute for the traditional liquid dye solutions. In this research, we designed and built a tunable solid dye laser device which consists of three main parts. (i) The active material producing the laser beam, which is a polymer rod [glycidyl methacrylate (GMA) polymer] doped with the laser dyes pyrromethene 597 (PM-597) or Nile blue (Nb-690). (ii) The pumping source is xenon linear flashlamp driven by a homemade power supply. (iii) Two broadband mirrors providing the optical feedback stable optical resonator. The properties of the gain medium and hence the laser emission characteristics were determined, and the results showed the efficiency of the homemade tunable solid dye laser device, that is suitable for a variety of applications. [ABSTRACT FROM AUTHOR]

Localized scleroderma (LS), commonly known as morphea, presents a significant clinical challenge due to its chronic, inflammatory nature affecting the skin and potentially underlying tissues. This systematic review explores the innovative approach of combining laser therapy and injectable fillers, specifically hyaluronic acid, for the treatment of LS. We conducted a comprehensive literature review following PRISMA guidelines, examining articles from MEDLINE/PubMed to assess the combined efficacy of these treatments in improving both esthetic and functional outcomes for LS patients. The search yielded 64 articles, with six selected for in-depth analysis for a total of nine patients, covering a range of patient demographics and treatment types. Our review highlights cases where fractional CO2 laser therapy promoted long-term tissue remodeling and instances where hyaluronic acid fillers effectively addressed skin atrophy and volume loss, enhancing both immediate and long-lasting esthetic improvements. The synergy between these treatments suggests a promising dual approach, aiming to maximize esthetic outcomes and to improve the quality of life for LS patients. This review underscores the necessity of further research to establish a comprehensive, evidence-based clinical pathway integrating both treatments for managing LS, thereby enhancing patient satisfaction and addressing the multifaceted nature of this challenging dermatological condition. [ABSTRACT FROM AUTHOR]

We report an investigation of a semiconductor disk laser (SDL) based on an InGaP/AlGaInP heterostructure emitting at a wavelength near 640 nm under in-well pumping by a pulsed rhodamine 6G dye laser with an emission wavelength of 601 nm. Use is made of structures with 25 quantum wells arranged in depth with a period of 193 nm. In a structure with a built-in Bragg mirror, a power of 3.5 W is reached at a wavelength of 642 nm with a slope efficiency of 7% with respect to the absorbed pump power. The achieved second harmonic power at a wavelength of 321 nm is approximately 30% of the maximum SDL power at the fundamental frequency. Under pumping above 250 W, the structure is destroyed due to strong adiabatic heating of the GaAs growth substrate. In a structure with a deposited broadband dielectric mirror, it is possible to reduce the adiabatic heating factor, implement double-pass pumping, and, accordingly, increase the supplied pump power. This makes it possible to obtain a pulse power of higher than 70 W at a wavelength of 645.5 nm with a slope efficiency of over 17%. [ABSTRACT FROM AUTHOR]

The Birt-Hogg-Dubé Syndrome (BHDs) can cause benign skin lesions like fibrofolliculomas as well as additional systemic symptoms like pulmonary cysts, kidney tumors, and recurrent pneumothoraces. We report the successful treatment of fibrofolliculomas in a patient with BHDs using a combination of fractionated ablative CO2 laser and a Flash Lamp Pulsed Dye Laser (FPDL). This combined method improves the CO2 healing process's functional and cosmetic results; while the first wavelength (ablative) has a greater capacity for excision and tissue regeneration, the second wavelength (non-ablative) provides more control over the tissue healing process. The lesions were successfully ablated up to the papillary dermis without leading to an enhancement in the overall textural appearance. Therefore, deeper laser ablations may be able to stop dermal residual lesion relapses. In conclusion, fractionated CO2 laser and FPDL can be used safely and effectively to reduce the appearance of facial hamartomas related to BHDs.

In this study, gold nanoparticle samples were prepared by the chemical reduction method (seed-growth) with 4 ratios (10, 12, 15 and 18) ml of seed, and the growth was stationary at 40 ml. The optical and structural properties of these samples were studied. The 18 ml seed sample showed the highest absorbance. The X- ray diffraction (XRD) patterns of these samples showed clear peaks at (38.25o, 44.5o, 64.4o, and 77.95o). The UV-visible showed that the absorbance of all the samples was in the same range as the standard AuNPs. The field emission-scanning electron microscope (FE-SEM) showed the shape of AuNPs as nanorods and the particle size between 30-50 nm. Rhodamine-610 (RhB) was prepared at 10-5 M concentration, the optical measurements were studied, AuNPs and RhB were mixed at ratios (1:1, 1:2, 1:3), and the fluorescence measurements were done. Full width at half maximum (FHWM) and the intensity of RhB after mixing were changed, and this result showed significant efficacy for many applications. The study shows that this mixing could be used after doping with polymer as a random gain medium or saturation absorber for pulse laser generation.

Introduction: The Flash‐lamp pulsed dye laser (FPDL) is nowadays considered the most precise laser currently on the market for treating superficial vascular lesions. In this study, we gathered data from 10 years of experience regarding dye laser treatment of patients presenting vascular malformations such as telangiectasia, rhinophyma, port‐wine stain, cherry and spider angioma and vascular tumours. Methods: Subjects were enrolled from 2013 to 2023 based on the vascular anomalies they presented. They underwent different treatment sessions with the FPDL device. Results: The age‐range distribution by vascular anomaly confirmed that haemangiomas are typical in children while rhinophyma is a condition very common in older adults. A difference in sex distribution showed that pathologies such as telangiectasias typically affect women whereas rhinophyma is more frequent in men. Most of the treatments interested the face area but no permanent side effects were registered. Conclusions: Our 10 years of experience with FPDL demonstrated good results in a wide range of applications for the treatment of different vascular anomalies. The absence of long‐term side effects and bearable pain during the treatment makes it a valuable solution for the resolution of benign tumours also in very young patients. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Physics is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Port-wine stains (PWS) are frequently refractory to laser treatments. The aim of this study is to evaluate the role of treatment interval time. From 1990, 216 patients underwent Pulsed Dye Laser sessions. The laser sessions were scheduled at a minimum interval of 4 weeks to a maximum of 48 weeks. Clinical outcomes were assessed 8 weeks after the last laser session. Better results were obtained with 8 weeks interval time between therapy session, and high efficacies were also found for intervals of 4, 6 and 10 weeks. For greater interval instead, the effectiveness is significantly lower. [ABSTRACT FROM AUTHOR]

Artificial red blood cells [i.e., hemoglobin vesicles (HbVs)] can be used as photosensitizers in pulsed-dye laser (PDL) treatment for port wine stains in animal models. Small HbVs are distributed in the vicinity of the endothelial cells of the blood vessels. In our previous in vivo experiments, both HbVs and red blood cells absorbed photons of the laser and generated heat, contributing to removal of very small blood vessels and large deeper subcutaneous blood vessels with PDL irradiation. Herein, we tested carbon monoxide-bound HbVs (CO-HbVs) that would produce heat energy while releasing CO in vessels after dye laser irradiation in a rabbit auricle model. We conducted this experiment to confirm secondary progression of thermal injury being reduced with the antioxidative property of CO. We histopathologically evaluated the damages to the large vessels and surrounding dermal tissue following PDL irradiation alone or subsequent to the intravenous injection of the qualified HbVs. The soft tissue damages were graded on a five-point scale and compared statistically. Intravenous CO-HbVs significantly reduced damage to the surrounding tissue after subsequent PDL irradiation; however, the degree of damage to the larger vessel wall resulted in a variety of changes, including a slight increase in our histopathological grades. This beneficial effect in dye laser treatment for port wine stains may be the result of the antioxidative property of CO against free radicals in the zone of stasis that may still be theoretically viable in burns. This effect of CO protecting tissues from thermal damage is consistent with previous reports of CO as a reducing agent. If the reducing agent can be delivered directly to the affected area immediately after the burn injury, even in a small amount, the complex inflammatory cascade may be reduced and unnecessary inflammation after laser treatment that lowers the patient's quality of life can be avoided. [Display omitted] • CO-bound artificial red blood cells reduced thermal damage by dye laser irradiation. • Antioxidants delivering directly to the affected area immediately after a burn. • Even in a small amount, it can reduce the secondary burn progression. [ABSTRACT FROM AUTHOR]

The processes of resonant interaction of short pulses of dye laser polychromatic radiation with plasma of a nanosecond discharge in neon with an extended hollow cathode are experimentally studied. Dispersion-type asymmetric optical transmission spectra of the plasma near the spectral absorption line of Ne I with a wavelength of 650.6 nm are detected during propagation of the laser radiation inside the cathode cavity while classical symmetric transmission spectra are formed during propagation of the laser radiation in the region between the electrodes. [ABSTRACT FROM AUTHOR]

Liquid dye lasers are intrinsically suitable for high-average-power operation because their flowing laser gain media can effectively remove the heat produced by laser amplification; thus, liquid dye lasers have a significant place in various laser applications. However, to sufficiently remove the dye solution heated by the laser, a very cumbersome dye flow system is required to achieve a high flow velocity in the dye cell of a high-power dye laser, which limits its applications. In this paper, we found that the pressure and power required to drive the high-speed dye flow are both proportional to the square of the laser beam size along the direction of the flow. Based on this result, we proposed a novel longitudinal pumping scheme that uses elliptical laser beams. This new scheme can significantly reduce the size and energy consumption of dye flow loops in high-power dye lasers. We also developed a dye laser system with a main amplifier using a 1 mm × 4 mm elliptical input laser beam. The amplifier produced an average power of 135 W with a repetition rate of 10 kHz and a conversion efficiency of 39.5%. The M 2 factor of the output beam was better than 1.7. The flow parameters to drive the dye flow loops were 2. 1 × 1 0 5 Pa, and 0.43 L/s, which gave a clearing ratio of 2 for the amplifier. This new pumping scheme enables high-power dye lasers to be more compact and efficient, making them more flexible for various applications. • The relationship between dye flow pressure and laser beam dimensions is investigated for the first time. • A new longitudinal pumping scheme is proposed and experimentally demonstrated. • Achieve an average output power of 135 W at a beam quality M 2 < 1. 7 [ABSTRACT FROM AUTHOR]

Covalent bonding between the Rhodamine B xanthene dye and polyurethanes, containing different isocyanate fragments (hexamethylene diisocyanate and toluene diisocyanate) has been realized and studied. Effects of polyurethane isocyanate components, different by chemical structure, on spectral properties of the Rhodamine B have been studied and discussed. Spectral, photophysical and lasing characteristics of the Rhodamine B dye, incorporated to the polyurethane matrices are presented. [ABSTRACT FROM AUTHOR]

We investigate the effects of 10.6 μm CO2 laser irradiation and 572 nm dye laser irradiation on optical properties and laser damage threshold of Nd:glass. We study the transmission, additional absorption (AA) spectra, and damage threshold of the samples before and after the irradiation. The results obtained indicate that irradiation of Nd:glass by pulsed CO2 and dye lasers is extremely effective for decrease of defects and increase in damage thresholds. The damage threshold of Nd:glass increases by a factor of 4.13 for dye laser and a factor of 3.1 for CO2 laser. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the effect of the pump energy and flow rate of the dye gain medium and one amplifier stage on the linewidth in a dye laser pumped by a frequency-doubled Q-switched Nd:YAG laser. A Fabry-Pérot etalon and imaging camera-based arrangement interfaced with a personal computer (PC) is used to measure the linewidth of the 565 nm laser line. [ABSTRACT FROM AUTHOR]

Introduction: Hemangiomas and vascular malformations are common vascular lesions. Although various methods have been described in the treatment of vascular lesions, the place of lasers is very important. Today, dye laser and Nd: YAG lasers are most commonly used in the laser treatment of vascular lesions. Materials and Methods: A total of 137 patients treated with 585–600 nm flashlamp pulsed dye laser and 1064-nm long-pulsed Nd: YAG laser in three laser units were searched, and laser setups and the number of sessions used were evaluated. Evaluations were made by three plastic surgeons over photographs. According to the discoloration and decrease in height of the lesion, it was classified as 0%–25% (poor), 25–50 (average), 50–75 (good), and 75–100 (excellent). The age of the patients ranged from 2 months to 55 years. 53 port-wine stain, 18 telangiectasia, 8 cherry angioma, 12 spider angioma, 18 hemangioma, 8 venous lake, 11 intraoral hemangioma, and 9 other vascular lesions constituted the distribution of diagnoses between patients. Laser power used in dye laser treatments ranged between 7 and 19 J/cm2, the mean sequence was 6.4, and duration ranged between 1.5 and 20 msec. Nd:YAG l laser power ranged between 120 and 240 J/cm2, the mean sequence was 2.8, and duration ranged between 10 and 50 msec. Results: Seventy patients (51.1%) achieved excellent results, 32 patients (23.36%) achieved good results, 14 patients (10.21%) achieved average clearance, and 21 patients (15.33%) showed low or no removal of their lesion. High success was achieved with minimal complications. Conclusion: Today, dye laser and Nd: YAG lasers provide a satisfactory aesthetic result, low morbidity, and effective treatment for many vascular lesions in terms of patient comfort. In order to optimize results and reduce negative effects, it is necessary to master the properties of the laser and have sufficient knowledge of the interactions of the laser with tissue.

An optical fiber is integrated in a polydimethylsiloxane substrate microfluidic channel. The laser gain medium consists of glycerol aqueous solution doped with rhodamine B (RhB) molecules, which has a lower refractive index (RI) than that of the optical fiber. The circular cross section of the optical fiber forms an optofluidic ring resonator and hosts high-quality (Q) whispering gallery modes (WGMs). Optically pumped along the fiber axis, lasing threshold properties of the RhB glycerol aqueous solution have been investigated. With the increase of both RhB dye concentration and the RI of the glycerol aqueous solution, the recorded lasing threshold decreases at first and then increases. Therefore, there is a best dye concentration as well as a best RI of the dye solution that corresponds to the lowest lasing threshold. Additionally, lasing threshold for the mixed solution of ethanol and ethylene glycol doped with RhB molecules is also demonstrated, which is much higher than that of the glycerol aqueous solution for the same dye concentration and the same RI of the dye solution. Based on evanescent wave pumped and gain coupled WGM lasing theory, we compute the lasing threshold varied with the dye concentration and the RI of the dye solution. The simulation results agree well with the experimental data.

The acronym PHACES stands for posterior fossa malformations, hemangiomas, arterial anomalies (cardiovascular or cerebrovascular), coarctation of the aorta/cardiac defects, eye abnormalities, and sternal defects. The characteristic dermatological clinical manifestation of PHACES syndrome is a segmental and extensive hemangioma, usually on the face. A combined therapy with 1,064 nm Nd-YAG/595-nm pulsed dye laser was performed in a young 15-year-old patient with PHACES syndrome, who presented a hemangioma on the left side of the face, located in the periorbital region. A first session with Nd-YAG laser (2,5 mm spot size, fluence 100 J/cm2, pulse duration 7 ms) for the treatment of teleangectasias and subsequently, three treatment sessions with pulsed dye laser (12 mm spot size, fluence 7 J/cm2, pulse duration 0,5 ms, repetition rate 0,6 Hz), once every 2 months, were performed. No postoperative complications were recorded, except for transient purpura after the pulsed dye laser sessions. The vascular lesion had a decrease in size bigger than 75%, and these results was maintained 6 months after the last treatment. Combined therapy Nd- YAG/pulsed dye laser is an effective and noninvasive procedure for hemangiomas in patients with PHACES syndrome.

Epidermal nevi (EN) are cutaneous hamartomas present at birth, usually occurs in the trunk, the face, or the limbs, appearing as a patch of overgrowing skin. They may be small and localized, but they may interest extensive areas of the body. A 20 years old man came to our attention for an EN interesting all the face. The treatment protocol consisted of a session of CO2 laser in order to vaporize thicker areas, followed by a session of dye laser on the area to prevent scarring. This treatment was performed under local anesthesia and sedation in three surgical sessions spaced 3 months from each other. Two sessions of dye laser spaced apart 6 months were performed during follow-up to further improve the esthetic outcome. The patient was followed for 2 years with no recurrence. Although surgery is still considered the gold standard in EN management, it is not always feasible. This novel combination technique can obtain optimal cosmetic results with no relapse within the period of follow up. Although further trials on a more significant number of patients are required, the combination of CO2 and dye laser promises to become a valid therapeutic alternative when treating giant EN of the face. [ABSTRACT FROM AUTHOR]

We report the mode locking regime of dye laser pumped by 400 ns laser diode pulses. Three green laser diodes operating at 513 nm are used as the pump source. We obtain subnanosecond pulse trains using periodic 1 ns pulse modulation of the power-supply current through the pump diodes. The addition of a saturable absorber results in both a decrease in the pulse duration to 0.2 ns and a good reproducibility of the output radiation.. [ABSTRACT FROM AUTHOR]

Background and Objectives: Warts are benign lesions of viral etiology characterized by a hyperkeratotic appearance tending to spread across the skin surface. Various treatments have been proposed to manage this condition, such as acids, imiquimod, photodynamic therapy, cryotherapy, and various lasers. Materials and Methods: In this paper, we describe a combination protocol using CO2 laser prior to Nd:YAG laser for lesions interesting the palmoplantar areas or dye laser for lesions on other skin surfaces in the management of non-facial warts resistant to traditional therapies. In total, 34 patients with 103 warts suffering from wart infection resistant to traditional therapies treated from 1 January 2019 to 1 June 2020 were retrospectively enrolled at the Dermatological Unit of Magna Graecia University (Catanzaro, Italy). Two dermatologists measured clinical results, classifying lesions with complete resolution, partial resolution, or non-responding. Patients at four months follow-up were asked to evaluate their degree of satisfaction with a visual analog scale (VAS). Results: Almost all patients reported the complete resolution of lesions, with no patient reporting scarring. Five patients reported hypopigmentation in the treated areas. The mean satisfaction level was high. Only three patients experienced a relapse of the condition. Conclusions: Using a vascular laser following a CO2 superficial ablation of warts may help reduce the risk of scarring and decrease the incidence of relapses for lesions resistant to traditional therapies. Therefore, more extensive studies will be necessary to confirm the obtained results.

A microcavity laser is reported using dye-doped cholesteric liquid crystals (CLCs) filled in a glass capillary with photo-alignment polyimide films. This laser runs based on the properties that a CLC has a refractive index much higher than that of glass, so whispering-gallery-mode (WGM) laser and distributed-feedback-mode lasers are included in the emission spectrum. We obtain a low threshold energy of 4.5 μJ · pulse-1 · mm-2, establish the shift of 3.04 nm of the WGMs in the temperature range 43-48 °C, and investigate electric field tunability.

Introduction: Hemangiomas and vascular malformations are common vascular lesions. Although various methods have been described in the treatment of vascular lesions, the place of lasers is very important. Today, dye laser and Nd: YAG lasers are most commonly used in the laser treatment of vascular lesions. Materials and Methods: A total of 137 patients treated with 585-600 nm flashlamp pulsed dye laser and 1064-nm long-pulsed Nd: YAG laser in three laser units were searched, and laser setups and the number of sessions used were evaluated. Evaluations were made by three plastic surgeons over photographs. According to the discoloration and decrease in height of the lesion, it was classified as 0%-25% (poor), 25-50 (average), 50-75 (good), and 75-100 (excellent). The age of the patients ranged from 2 months to 55 years. 53 port-wine stain, 18 telangiectasia, 8 cherry angioma, 12 spider angioma, 18 hemangioma, 8 venous lake, 11 intraoral hemangioma, and 9 other vascular lesions constituted the distribution of diagnoses between patients. Laser power used in dye laser treatments ranged between 7 and 19 J/cm², the mean sequence was 6.4, and duration ranged between 1.5 and 20 msec. Nd:YAG l laser power ranged between 120 and 240 J/cm², the mean sequence was 2.8, and duration ranged between 10 and 50 msec. Results: Seventy patients (51.1%) achieved excellent results, 32 patients (23.36%) achieved good results, 14 patients (10.21%) achieved average clearance, and 21 patients (15.33%) showed low or no removal of their lesion. High success was achieved with minimal complications. Conclusion: Today, dye laser and Nd: YAG lasers provide a satisfactory aesthetic result, low morbidity, and effective treatment for many vascular lesions in terms of patient comfort. In order to optimize results and reduce negative effects, it is necessary to master the properties of the laser and have sufficient knowledge of the interactions of the laser with tissue. [ABSTRACT FROM AUTHOR]

This paper describes a high-pulse-energy frequency-doubled ultraviolet dye laser operating at a repetition rate of 500 Hz. The pump source is a laser-diode side-pumped Q-switched Nd:YAG laser with a pulse energy of 29 mJ at 532 nm. A master oscillator power amplifier is employed to amplify the output pulse of the dye laser to 8.1 mJ at 566 nm, and by frequency doubling with BBO crystal a pulse energy of 1.7 mJ at 283 nm is achieved with a pulse width of 8 ns. This is more than four times the largest reported pulse energies generated by other fixed-frequency dye lasers when operating at repetition rates of more than 1 kHz. The conversion efficiency and stability of dye laser are discussed, which show the potential for high-speed laser diagnostics in the fields of combustion and turbulent flow detection. [ABSTRACT FROM AUTHOR]

The novel and sensitive In-Gas Laser Ionization Spectroscopy (IGLIS) technique enables high-precision laser spectroscopy of the heaviest elements and isotopes very far from stability that are produced in fusion-evaporation reactions at in-flight separators. Powerful and dedicated laser systems are required in these facilities to realize in-gas jet laser spectroscopy with optimal spectral resolution and efficiency. The performance with respect to the requirements for IGLIS studies at the low energy front-end of the Super Separator Spectrometer (S3) at GANIL, France, of Dye and Ti:sapphire laser systems is investigated. In addition, a number of specific experimental cases on key isotopes of the elements Ag, Sn, Ac, and No are discussed in detail. [ABSTRACT FROM AUTHOR]

A propelling mixture of 1 mMof Rh6G in ethanol has been used for the determination of several tuneable laser lines with the help of five pairs of 2nd harmonics of a passively Q-switched and mode locked Nd:YAG laser. The time gap between exciting pulses was speckled along a rationality length of 1 cm. Mirror straddling stages having microcontrollers were used for the fine tuning of wavelengths. It has been observed that lasing lines quantity has the range of variation from lowest value of 5 to highest value of 18 across wavelengths of 540 to 590 nm. The measurement of pulse lengths was also performed using a streak camera in order to check variance starting from the lowest level of 10 ps to the extreme of 30 ps. [ABSTRACT FROM AUTHOR]

This article describes the random lasing (RL) phenomenon obtained in a dye-doped, polymeric double-phase system composed of PMMA and PVK polymers. It shows how relative concentrations between mentioned macromolecules can influence lasing parameters of the resulting blends, including obtained emission spectra and threshold conditions. We describe the influence of lasers’ composition on their morphologies and link them with particular RL properties. Our studies reveal that the disorder caused by phase separation can support the RL phenomenon both in the waveguiding and quasi-waveguiding regimes. Changing the relative concentration of polymers enables one to switch between both regimes, which significantly influences threshold conditions, spectral shift, number of lasing modes, and ability to support extended and/or localized modes. Finally, we show that a simple phase separation technique can be used to fabricate efficient materials for RL. Moreover, it enables the tailoring of lasing properties of materials in a relatively wide range at the stage of the laser material fabrication process in a simple way. Therefore, this technique can be seen as a fast, cheap, and easy to perform way of random lasers fabrication.

Highlights • In house built dye laser and mass-spectrometer confirms high isotope selectivity. • Measured ratio (6Li/7Li ≈ 0.080) is found in close agreement with literature. • Concentration of 6Li isotope get enhanced remarkably from 7.5 up to over 72% • Measured photoionization cross-section are 6Li (15.5 ± 2.1 Mb), 7Li (18.6 ± 2.4 Mb) • Proposed energy pathway of photoionization yields ∼10 folds 6Li isotope enrichment. Abstract Laser assisted isotope separation of lithium is carried out by isotope-selective two-step photoionization method using time of flight mass-spectrometer. The isotopes of lithium are important for nuclear industry. A narrowband tunable dye laser in combination with mass-spectrometer on tuning with 6Li (2S 1/2 → 2P 1/2) and 7Li (2S 1/2 → 2P 3/2) resonance levels confirms high degree of isotope selectivity (∼32). Both the dye laser (∼0.2 cm−1, 6 ns, 640–680 nm) and the mass-spectrometer are developed in-house and optimized. Measured relative isotopic abundance (6Li/7Li ≈ 0.080) is found in close agreement with literature. It is also found that concentration of naturally less abundant (6Li) isotope get enhanced remarkably from 7.5% up to over 72% upon precise tuning of the dye laser to 6Li (2S 1/2 → 2P 1/2) resonance level. Photoionization cross-sections of both the isotopes are measured as 6Li (15.53 ± 2.1 Mb) and 7Li (18.62 ± 2.4 Mb) for 2p excited state using more popular and accurate saturation technique, whereas number density are determined as N 0 ≈ 5.9 × 109 and 5.62 × 1010 atoms/cm3 respectively. It is inferred that selected energy pathway [2S 1/2 → ∼671 nm → 2P 1/2, 3/2 → ∼337 nm → 1S 0 (Li+)] gives high photoionization yield and the large (∼10 folds) isotope enrichment. [ABSTRACT FROM AUTHOR]

Highlights • A pulse-burst dye laser at 10 kHz repetition rate is presented for the first time. • Single pulse energy achieves 1.45 mJ at 280 nm at 10 kHz repetition rate. • Frequency doubling efficiency is higher than previous laser at this repetition rate. • OH-PLIF images are taken and show the promising application. Abstract In this paper, we present a dye laser operated under burst mode with minimum pulse interval 0.1 ms, corresponding to repetition rate 10 kHz. Pulse energy of 7.77 mJ with efficiency of 26.7% is achieved at 560 nm by using rhodamine 6G solution in methanol as the gain medium when the energy of pump energy is 32.4 mJ at 532 nm. The tunable range is found from 545.3 nm to 573.1 nm for fundamental and 272.5 nm to 286.9 nm after frequency doubling with maximum pulse energy 1.45 mJ at 280 nm, which indicates the frequency doubling efficiency is 18.7%. OH-PLIF images with time interval 0.1 ms are gotten using the dye laser, which proves the feasibility of this dye laser applied in dynamic laser diagnosis fields. [ABSTRACT FROM AUTHOR]

Highlights • Absolute photoionization cross-section is measured for 6Li(2p2P 1/2 , 3d2D 5/2) states. • A low cost and extremely sensitive thermionic diode used, is in-house developed. • High SNR photoionization signals are obtained even for weak two-photon excitation. • Measured cross-sections 15.40 ± 2.8 Mb, 8.04 ± 1.6 Mb well agree with reported data. • Isotopic shift (∼ 10.53 GHz) measured for Li (2p) states agree with reported data. Abstract Studies on photoionization cross-section measurement of lithium 2p and 3d excited states selectively populated by single and two photons are reported. The photoionization is carried out in a heat-pipe cum thermionic diode detector using nitrogen laser pumped pulsed dye laser. Rhodamine perchlorate (Rh-640) dye is used to generate the desired tunable laser output in the range of 635 to 675 nm. Both, the thermionic diode detector and dye laser are developed in-house. A negative space charge region formed around diode cathode filament is illuminated by dye laser exciting pulse followed by ionizing UV radiation from nitrogen laser. The effect of ionizing laser pulse energy and precise tuning of dye laser on photoionization signal, across 670.780 nm (2S 1/2 → 2P 1/2,3/2) single-photon transition and 639.145 nm (2S 1/2 → 2D 3/2,5/2) two-photon transition are studied. The results obtained are compared with model calculations of photoionization signal saturation curve. The ionization cross-section for both the states (2P 1/2 , 2D 5/2) are determined as 15.40 ± 2.8 Mb and 8.04 ± 1.6 Mb, respectively and atomic number density N ∼ 5.6 × 108 (cm−3). [ABSTRACT FROM AUTHOR]

Application of DNA to photonics and electronics was proposed by Naoya Ogata in 1990s. Utilizing its specific structure, ability to complex formation, and affinity to various organics, many types of complex materials have been synthesized and reformed with various techniques by Ogata and his collaborators, showing promising functionalities for practical applications. Application field ranged over very wide area from photonics as dye laser, nonlinear optics, photonic switch, electroluminescence, and optical waveguide device to biological and medical applications. Research activities on DNA materials are still expanding at the moment. This review aims to give a concise overview of his pioneering works in this new field and their impacts on science and engineering. [ABSTRACT FROM AUTHOR]

We demonstrate an omnidirectional laser from a 3-D Bragg microcavity, which is fabricated from a cholesteric liquid crystal that is doped with reactive mesogen. The wavelength of the laser is found to be determined by the position of the photonic bandgap that was formed within the 3-D Bragg microcavity. Compared with the laser from pure cholesteric liquid crystal microcavity, a rigid polymer network is formed within the microcavity due to the doped reactive mesogen. The polymer network successfully enhances the resistance ability of the 3-D Bragg microcavity to higher pump power by 1.5 times, thus leading to a more stable laser based on it. This laser may have potential use in optics, displays, and other photonic devices.

We demonstrate the emission characteristics, including polarization property and temperature effect, of lasing from all organic mirrorless quasicrystal fabricated by seven-beam interference. The output lasing is linearly polarized with polarization direction confined within the 2-D plate that aperiodic quasicrystal formed. With an increase of temperature, lasing peaks blue-shift that is related to the change of refractive index of liquid crystal, as well as phase transition from liquid crystal phase to isotropic phase. The transmission spectrum of quasicrystal that is calculated by finite-difference time-domain (FDTD) simulation blue shifts with the increased temperature, which can be used to explain the underlying mechanism of the blue-shift of lasing peaks.

The acronym PHACES stands for posterior fossa malformations, hemangiomas, arterial anomalies (cardiovascular or cerebrovascular), coarctation of the aorta/cardiac defects, eye abnormalities, and sternal defects. The characteristic dermatological clinical manifestation of PHACES syndrome is a segmental and extensive hemangioma, usually on the face. A combined therapy with 1,064 nm Nd-YAG/595-nm pulsed dye laser was performed in a young 15-year-old patient with PHACES syndrome, who presented a hemangioma on the left side of the face, located in the periorbital region. A first session with Nd-YAG laser (2,5 mm spot size, fluence 100 J/cm2, pulse duration 7 ms) for the treatment of teleangectasias and subsequently, three treatment sessions with pulsed dye laser (12 mm spot size, fluence 7 J/cm2, pulse duration 0,5 ms, repetition rate 0,6 Hz), once every 2 months, were performed. No postoperative complications were recorded, except for transient purpura after the pulsed dye laser sessions. The vascular lesion had a decrease in size bigger than 75%, and these results was maintained 6 months after the last treatment. Combined therapy Nd- YAG/pulsed dye laser is an effective and noninvasive procedure for hemangiomas in patients with PHACES syndrome. [ABSTRACT FROM AUTHOR]

In this article, the lasing characteristics of a dye Neutral Red in spectroscopic grade ethanolic solutions is reported. The lasing emission spectra for a dye concentration of 0.35 mg/L were studied using an Nd: YAG laser operating at a wavelength of 532 nm. The absorption peak and emission peak of the dye was found to be at 533 nm and 614 nm respectively. The quantum yield of the dye was calculated to be 0.8. The dye exhibited better photostability with a low lasing threshold of 8.8 mJ and a gain coefficient of 31 cm −1 . The lifetime of the dye obtained was 9.7*10 −10  s. From the present study, we came to a conclusion that the dye under study is a much promising candidate for lasing applications. [ABSTRACT FROM AUTHOR]

Objectives The characteristics of dye laser such as purity, concentration and dye solvent velocity have significant effects on the output power of laser. The main objective was to investigate the effects of the dye solvent velocity on the laser output power. Methods/Statistical analysis A homemade ring dye laser (Rhodamine 6G) was used and the liquid dye was injected by a liquid jet and pumped by beam of a 6 W argon ion laser (λ = 488 nm). By using mechanical pumping, the liquid pressure was controlled and different velocities were selected. Findings It was observed that by increasing the pressure, the output power of dye laser, was increased initially and then in a certain pressure variation region (0.65–0.69 MPa), some slight changes were detected. By increasing more dye liquid pressure, the laser output was decreased considerably. The maximum output laser power obtained in a wavelength ranges within 5702–6072 Å, was approximately 140 mW. It was seen that by increasing the pumping power, the dye laser output power was increased. Moreover, for each specific wavelength, there was a threshold power (in pumping laser) for dye laser emission in order to be initiated. For example for the laser emission at 5763 Å and 5990 Å, the minimum pumping laser powers are ~4.1 and 5.2 W, respectively. Dye solvent velocity in output power of dye laser is not appropriately discussed in previous studies, so it can be stated that in the current study, it was carried out with different conditions. Application/Improvements Applying suitable dye solvent velocity is one of the important issues in designing ring dye laser that has been correctly discussed and utilized in the current study. [ABSTRACT FROM AUTHOR]

We demonstrate pump angle and position effects on lasing from all organic quasicrystal fabricated by nine-beam interference. The output wavelengths of lasing are experimentally investigated with different pump angles. The underlying mechanism is explained by the photonic band edge simulated by finite-difference time-domain method. Additionally, the position effect on lasing is also demonstrated, and the emission characteristics of lasing are studied. The mirrorless laser is featured by low cost, and simple fabrication, which enables quasicrystal based on holographic polymer-dispersed liquid crystal an all organic miniature lasing devices. [ABSTRACT FROM AUTHOR]