Ruby laser

About: Ruby laser is a research topic. Over the lifetime, 2474 publications have been published within this topic receiving 38933 citations. The topic is also known as: corundum laser & ruby rod.

Stimulated emission from polymethine dyes

Abstract: Stimulated emission is reported for two polymethine dyes dissolved in glycerol when pumped by a Q‐switched ruby laser. The materials are 1, 1'‐diethyl‐2,2'‐dicarbocyanine iodide, and 1, 1'‐diethyl‐4, 4'‐carbocyanine iodide. The emission wavelength is variable over the range 750 nm to 790 nm, depending on cell length. Oscillation has been observed on both the 0–0 and 0–1 vibrational transitions.

Orientation and velocity dependence of solute trapping in Si

Abstract: Interface segregation coefficients have been measured for Bi in Si for melt growth as a function of velocity for (111) and (100) crystals. Surface layers were melted by ruby laser irradiation and liquid‐solid interface velocities varied from 0.8 to 5 m/s by changing Si substrate temperatures or laser pulse length. Segregation coefficients are strongly dependent on velocity and orientation in this range.

Laser hair removal: guidelines for management.

Abstract: Laser-assisted hair removal is the most efficient method of long-term hair removal currently available. Several hair removal systems have been shown to be effective in this setting: ruby laser (694nm), alexandrite laser (755nm), diode laser (800nm), intense pulsed light source (590 to 1200nm) and the neodymium:yttrium-aluminium-garnet (Nd:YAG) laser (1064nm), with or without the application of carbon suspension. The parameters used with each laser system vary considerably. All these lasers work on the principle of selective photothermolysis, with the melanin in the hair follicles as the chromophobe. Regardless of the type of laser used multiple treatments are necessary to achieve satisfactory results. Hair clearance, after repeated treatments, of 30 to 50% is generally reported 6 months after the last treatment. Patients with dark colored skin (Fitzpatrick IV and V) can be treated effectively with comparable morbidity to those with lighter colored skin. Although there is no obvious advantage of one laser system over another in terms of treatment outcome (except the Nd:YAG laser, which is found to be less efficacious, but more suited to patients with darker colored skin), laser parameters may be important when choosing the ideal laser for a patient. Adverse effects reported after laser-assisted hair removal include erythema and perifollicular edema, which are common, and crusting and vesiculation of treatment site, hypopigmentation and hyperpigmentation (depending on skin color and other factors). Most complications are generally temporary. The occurrence of hypopigmentation after laser irradiation is thought to be related to the suppression of melanogenesis in the epidermis (which is reversible), rather than the destruction of melanocytes. Methods to reduce the incidence of adverse effects include lightening of the skin and sun avoidance prior to laser treatment, cooling of the skin during treatment, and sun avoidance and protection after treatment. Proper patient selection and tailoring of the fluence used to the patient’s skin type remain the most important factors in efficacious and well tolerated laser treatment. While it is generally believed that hair follicles are more responsive to treatment while they are in the growing (anagen) phase, conflicting results have also been reported. There is also no consensus on the most favorable treatment sites.

Tattoo removal with the Q-switched ruby laser and the Q-switched Nd:YAGlaser: a comparative study.

Abstract: The Q-switched ruby and the Q-switched neodymium YAG lasers are both widely used in the treatment of amateur and professional tattoos. Comparative evaluation of these two laser systems has not previously been performed; thus, the advantages of each laser have not been delineated. Forty-eight amateur and professional tattoos were treated with both the Q-switched ruby and Q-switched Nd:YAG lasers. The tattoos were divided in half and one side of the tattoo was treated with each laser. After one treatment, the patients returned for evaluation to assess the degree of lightening achieved by each laser. The Q-switched ruby laser was found to be superior in lightening black dye in both professional and amateur tattoos. A significant advantage was noted for the ruby laser in the removal of green tattoo pigment. The differences with the Q-switched ruby laser and the 1064 nm option of the Q-switched YAG laser were not clinically significant in the lightening or removal of other colors. The 532 nm option of the Q-switched YAG laser was superior to the Q-switched ruby and the 1064 nm option of the YAG laser in the removal of red tattoo colors in professional tattoos. Hypopigmentation was found more commonly with the Q-switched ruby laser, while textural change was noted more commonly with the Q-switched Nd:YAG laser. One of the patients treated with the Nd:YAG laser at 1064 nm showed a hypertrophic scar.

Calculated temperature distribution during laser annealing in silicon and cadmium telluride

Abstract: By solving the time-dependent heat flow equation, the temperature reached by silicon and cadmium telluride surface layers under high power density ruby laser pulsed illumination, is calculated. The results are presented in directly useful figures allowing the determination of the surface temperature, its evolution towards the bulk as a function of time... In particular, it should be noticed that for a 25 ns half-power width, pulses of 0.8J/cm2 are sufficient to melt the top of an amorphous silicon layer, this value becomes noticeably lower for cadmium telluride.