Showing papers on "Ruby laser published in 2005"

Our approach to pediatric dermatologic laser surgery.

Abstract: Background and Objectives Many pediatric dermatological conditions may be successfully treated with laser surgery. Study Design/Materials and Methods The clinical approach to various pediatric dermatological conditions utilizing laser treatment options is discussed. Results Clinical uses of various modalities such as pulsed dye laser, KTP laser, Nd-YAG laser, Q-switched ruby laser, erbium-YAG laser, diode laser, non-coherent blue light sources, and fractional resurfacing are presented with successful parameters, developed over 22 years, utilized on a daily basis in a laser surgery clinic. Conclusion Laser surgery can make a significant improvement in many pediatric skin lesions, thanks to the unique properties of pediatric skin and a vast array of laser technologies. Lasers Surg. Med. 37:255–263, 2005. © 2005 Wiley-Liss, Inc.

Treatment of congenital melanocytic nevi using the combined (normal-mode plus Q-switched) ruby laser in Asians: clinical response in relation to histological type.

Abstract: Clinical response of congenital melanocytic nevus (CMN) to the combined normal-mode ruby laser (NMRL) and Q-switched ruby laser (QSRL) treatment method (ie, NM plus QS) was correlated with the histologic depth of nevomelanocytic nests to predict the efficacy rate and therapeutic outcome of the laser treatment. Thirty-four patients with CMN were treated using the combined (NM plus QS) ruby laser method. The clinical results of the laser treatment demonstrated that 20 had excellent response, 11 had good response, 3 had fair response, and there was no poor response. When correlated with the histologic type, the efficacy rate of the combined ruby laser was significantly higher in the superficial intradermal type than in the others. We conclude that combining the NMRL and QSRL with appropriate parameters to target both superficial and deep nevomelanocytic components provides a greater degree of penetration of laser light.

Effect of pulsed laser action on hole-energy spectrum of Ge/Si self-assembled quantum dots

Abstract: Space-charge spectroscopy has been used to study the hole energy spectrum of an array of Ge quantum dots (QD's) coherently embedded in a Si matrix and subjected to a ruby laser $(\ensuremath{\lambda}=694\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ nanosecond irradiation ex situ. The laser energy density in a single pulse was near the melting threshold of the Si surface. The number of laser pulses was varied from 1 to 10, and the duration of each pulse was $80\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$. From the capacitance-voltage characteristics, temperature- and frequency-dependent admittance measurements, the energies of holes confined in Ge QD's were determined. The pulsed laser annealing was found to result in a deepening of the hole energy level relative to the bulk Si valence band edge and in a decrease of the hole energy dispersion. After the treatment with ten laser pulses, the spread of the hole energies due to varying sizes of the QD's within the ensemble was reduced by a factor of about 2. The obtained results give evidence for a substantial reduction of the QD's size dispersion and for a narrowing distribution of the hole energy levels stimulated by nanosecond laser irradiation. A possible explanation of the improved uniformity of QD's sizes involves dissolving small size Ge QD's in a Si matrix by pulsed laser melting of the Ge nanoclusters and their subsequent intermixing with surrounding solid Si.

Dynamics of Laser-Induced Phase Transitions in Cadmium Telluride

Abstract: A numerical simulation of the dynamics of phase transitions induced by nanosecond pulsed radiation from a ruby laser in CdTe has been carried out. It is shown that evaporation of Cd atoms results in cooling of the surface; consequently, a nonmonotonic profile of the temperature field is formed, with the maximum temperature being attained in the bulk of the semiconductor at a distance of about 10–30 nm from the surface. At radiation energy densities above the threshold, the molten state formed under the surface extends both to the surface and into the depth of the semiconductor. Crystallization also proceeds in two directions, namely, from the surface into the depth of the samples due to the growth of nucleation centers in the melt, which is highly depleted in Cd atoms under the conditions of intense heat removal, and from the substrate to the surface due to epitaxial growth.

Treatment of fireworks tattoos with the Q-switched ruby laser.

Abstract: Background. The best approach in managing patients with explosive traumatic tattoos is the immediate removal of particles during initial care. Delayed treatment makes the situation more difficult to manage. Under certain conditions, a Q-switched ruby laser can be considered an excellent alternative. Methods. We report a new case of multiple facial fireworks tattooing managed successfully with a Q-switched ruby laser under low fluency pulses at 4.5 J/cm2. A pretreatment test zone was initially performed, and then three treatments were conducted at 6-week intervals. Results. More than 75% of the lesions were removed without scarring. Conclusion. The Q-switched ruby laser can be a safe and excellent choice for the removal of explosive particles.

Phase Transition on Surface of IV Group Semiconductors by Laser Radiation

Abstract: Analysis of a reordering of Ge amorphous surface by ruby laser; kinetics of the surface annealing after ion implantation using the optical reflectivity; occurrence laser induced periodical structures; nanohills formation by YAG:Nd laser allowed us to resume common features for these process which belong to thermogradient effect, too. Experimental data on annealing of p-Si (111) and i-Ge (111) mechanically polished surfaces by YAG:Nd laser radiation using of optical and atomic force microscopes optical reflectivity of He-Ne laser and the four-probe method confirmed a main role of termogradient effect in the process reordering of the mechanically damaged surface of Si and Ge single crystal. It was found that row of nanostructures arises on the irradiated surface of p-Si single crystal after irradiation by YAG:Nd second harmonic. For explanation this effect gathering of interstitial atoms at the irradiated surface is proposed.

How well does your ruby laser work

Abstract: The safe and effective use of cutaneous lasers is dependent upon the selection of a clinically appropriate laser energy level. Therefore, the accuracy of the stated laser output is critical. The energy output of an Aesculap ruby laser was recorded at the start of every clinical session over a 704-day period using an external energy meter. Regular review of these records enabled trends of energy output to be recognised and appropriate action to be taken prior to adverse clinical sequelae. This monitoring procedure is a quick and inexpensive method of improving quality control in the use of medical lasers.

Comparative study between Ruby, Alexandrite and Diode lasers in hirsutism

Abstract: Background: Hirsutism is a common problem for which laser is being the treatment of choice. Several lasers with varying wavelengths, pulse durations, energy fluences and skin cooling systems, are currently used for hair removal. However, the ideal laser parameters and group of patients who respond better after treatment remain largely unknown. Objectives: A prospective study to evaluate the long term efficiency and safety of three different (Ruby, Alexandrite, Diode) laser hair reduction systems and to determine which candidates respond better for hair reduction. Methods: 171 female patients with Fitzpatrick skin types II- IV with the problem of hirsutism, in the beard area were divided into three groups. Group one included 60 patients, who were treated by ruby laser; group two included 51 patients who were treated by Alexandrite laser whereas the third group included 60 patients who were treated by diode laser. Detailed history, Hormonal assay and abdomino-pelvic ultrasonography were performed to differentiate between idiopathic and pathological hirsutism. Treatment was

The formation of nanodimensional structures on the surface of p-CdTe crystals exposed to a single radiation pulse from a ruby laser

Abstract: The formation of nanodimensional structures on the surface of p-CdTe crystals has been studied as a function of the radiation-power density of a laser under a single irradiation dose. The best conditions for laser irradiation of the crystals are found. Under these conditions, a homogeneous structure with a period of 100 nm is formed. The lateral size of the structure is ∼(19–20) nm, and the average height is ∼(3.40–9.38) nm. It is found that periodicity manifests itself clearly in one crystallography direction.

Multiposition Multipass Thomson Scattering Diagnostic for Tokamak NOVA-UNICAMP

Abstract: In this article, the use of an 8×8-matrix independent 10-stage dynode multichannel photomultiplier for multipass Thomson scattering is described. Light from a pulsed ruby laser is irradiated 12 times in the central region of plasma using the resonator cavity of a multipass system, and integrated scattered light is detected for the first time using the multichannel photomultiplier XP1752 from Philips. The simultaneous measurements of electron temperature and density at four spatial positions, which can be extended by increasing the numbers of Analog-to-Digital Converter (ADC) channels and signal output windows, have been performed throughout full discharge by a shot-to-shot procedure. An electron temperature Te of 50 eV and a density ne of 5×1012 cm-3 were measured for the tokamak NOVA-UNICAMP. Because of the use of a low-power ruby laser (typically 1 J) and scattered light amplification using a multipass system, the level of stray light was kept low and absolute density measurements were made possible by nitrogen Rayleigh scattering.

Formation of C2nH2 Polyynes by Laser Ablation of Graphite, Coal or C60 Particles Suspended in Selected Solvents

Abstract: Compared with extensive studies on the formation of carbon clusters by laser ablation of graphite in the gas phase since the discovery of C60 [1], little work has been done on the laser ablation of graphite in the liquid phase, except for the following pioneering studies [2,3]. Fojtik and Henglein [2]studied laser ablation of small graphite particles in solutions using a focused 694 nm ruby laser beam of 500 J/cm2 with a long pulse period of about 1ms. In the product analysis, using the high-performance liquid chromatography (HPLC), they obtained three peaks of C60, C70, and C80-C90 fullerenes in toluene solution. They found that the relative intensity of C70 peak was unusually stronger than that of more stable C60 peak. Gaumet et al. [3] studied laser ablation of a graphite cylinder in benzene using a focused 266, 532, and 1064 nm YAG laser (180mJ/pulse) with a short pulse period of about 10 ns. On the basis of a product analysis using gas chromatography/ mass spectrometry (GC/MS), they obtained experimental evidence for the formation of small C1, C2, C3, and C4 carbon clusters by laser vaporization of graphite in solution. Two types of laser reactions were observed: addition of carbon clusters to a phenyl radical and aggregation of carbon clusters resulting in hydrogen-capped C2nH2 (n¼ 4 and 6) polyynes.

The development of laser surgery and medicine in China

Abstract: The first Chinese ruby laser was created in 1961 and it was adopted for the retina coagulation experiment in 1965. Since 1970's, lasers had been widely applied clinically including the diseases suitable to physical therapy or acupuncture. The Chinese HpD was first produced in 1981 and first case of PDT was treated using Chinese HpD and Chinese lasers in the same year. Its success brought attention establishing a research group supported by the government in 1982. A nationwide systemic research project on PDT was then carried out. The step taken for PDT also accelerated the development of various fields of laser medicine and surgery. Laser treatments had been commonly adopted in the clinics and hospitals for the diseases of the superficial lesions and the lesions can be reached by the endoscopes non-invasively in 1980's. Since 1990's, the interventional laser therapies adopted mainly were percutaneous laser angioplasty, laser treatments through laparoscope, thoracoscope, arthroscope, neuro-endoscope etc. Ultrasound guided percutaneous laser heat coagulation for small hepatic cancer revealed good results and ultrasound guided percutaneous PDT for advanced large liver cancer revealed unexpected results after five years follow-up. At present: There are more long-term follow-up patients in the clinical trial; more advanced commercial available lasers and new techniques are adopted. Since the popularization of scanning electron microscope, laser scanning confocal microscope, laser induced auto-fluorescence system, high sensitivity fluorescence microscopic imaging system etc. in the laboratories, the basic studies can be more advanced and some times, the sub-cellular level can be reached; ultra-structure histo-morphology and gene studies are involved. In dermatology, Q-switched Alexandrite laser and other Q-switched lasers are used mainly for the treatment of skin pigmentation and vascular diseases; pulsed dye laser, ultra-pulsed CO 2 laser are used in resurfacing, facial acne scar, osmidrosis etc. For ophthalmology, excimer laser are used for myopia or hyperopia; argon green laser, krypton yellow laser are adopted in coagulation for retinal detachment and neovascularization etc. Lasers are often used for the canaliculoplasty in the lacrimal canal. Low level lasers had been used very often on the acupuncture points and for many chronic diseases. Intravascular low level laser irradiation adopting semiconductor lasers and He-Ne laser were reported to use for comatose patients, schizophrenia, vascular dementia, Alzeimer's disease and coronary disease. Reports from laboratory studies in the field of low level laser demonstrated the stimulation effect on the cells and immunology system; inhibitory effect on proliferation; it improved the biomedical data in hemorrheology; promoted the spinal motor nerve cell function, axonal regeneration; increased epidermal Langerhams cell to improve the antigen function, increased myocardial capillary permeability. Intra-coronary low power red laser irradiation assisted coronary interventional therapy showed its prevention effect on restenosis. Studies about the effects of various kinds of lasers, their wavelength, power densities and doses on various kinds of tissues were reported.

The problem of the creation stable p-n junctions with help the methods of relaxed optics in InSb and InAs

Abstract: The basic problems of the receiving p-n junctions in ion implanted Mg/sup +//InSb after CO/sub 2/-laser irradiation and in p-InSb and p-InAs after ruby laser irradiation are represented. Proper volt-ampere characteristics are analyzed. The basic physical mechanisms of receiving these structures are discussed too. A basic cause of the difference these p-n junctions is various mechanisms of irreversible interaction light and semiconductor (self-absorption for ruby laser irradiation and "damage"-absorption for CO/sub 2/-laser irradiation).

Laser Treatment of Hard Tissue Lesions

Abstract: 1905 Based on this theory, Maiman developed the ruby laser in 1960 Since then, several types of laser devices have been developed and used in medicine and dentistry, as well as engineering and measurement sciences The first application of laser in the mouth was the surgical treatment of tumors in the oral cavity, and various lasers – including semiconductor diode, carbon dioxide, helium-neon, neodymium:YAG, argon, erbium:YAG, and erbium, chromium:YSGG – have since been developed and applied in dentistry In addition, excimer and free-electron lasers are currently being investigated Dentists throughout the world have raised questions concerning not only the validity of laser therapy in dentistry, but also the methods used to perform laser treatment techniques The present paper describes the current and possible future clinical indications, laser devices, assessment methods, and mechanisms in the field of laser treatment of hard tissue lesions CARIES DIAGNOSIS