Dye lasers use a dye solution as an active medium. Dye lasers are generally used in skin treatment. Dye lasers output is a short pulse of broad spectrum content with a high achievable gain. Compared to gases and most solid-state lasing media, a dye can actually be used for a much wider range of wavelength. The wide bandwidth makes them particularly suitable for tunable lasers and pulsed lasers. Moreover, the dye can be replaced by another type in order to generate different wavelengths with the same laser, although this usually requires replacing other optical components in the laser as well. Dye lasers have become an important part of laser surgery.
Dye lasers have a basic construction. Since organic dyes tend to degrade under the influence of light, the dye solution is normally circulated from a large reservoir. The dye solution can be flowing through a cuvette (a glass container), or be as a sheet-like stream in open air from a specially-shaped nozzle. Some of the dyes used in dye lasers are rhodamine 6G, fluorescein, coumarin, stilbene, umbelliferone, tetracene and malachite green. Adamantane is added to some dyes to prolong their life. With a dye jet, reflection losses from the glass surfaces and contamination of the walls of the cuvette are avoided. These advantages come at the cost of a more-complicated alignment. A pulsed dye laser (PDL) uses a beam of light at a specific wavelength and is used for conditions or spots on the skin which are made up of blood and blood vessels. A pulsed dye laser selectively destroys small blood vessels in the under layer (dermis) of the skin without damaging the surrounding tissue or outer layer of the skin (epidermis). Cycloheptatriene and cyclooctatetraene (COT) can be added as triplet quenchers for rhodamine G, increasing the laser output power. Output power of 1.4 kilowatt at 585 nm can be achieved using Rhodamine 6G based pulse dye laser with COT in methanol-water solution. Pulsed dye laser can be used for all ages and all skin types. Dye lasers are designed and manufactured to meet most industry needs.
Dye lasers are used in many applications. Examples include their use to treat scars on the body. Birthmarks such as spider veins on the face, changes of rosacea, port wine stains, small cherry angiomas on the body, and some other scars are best treated with pulse dye laser treatment. A pulse dye laser is used to treat vascular lesions like port wine stains, nevus flemmus, hemangiomas, keloids, and hypertrophic scars. A pulse dye laser is also used to treat pigmented nevi. A long pulsed dye laser is used to treat fine veins, telangiectasia, and blushing. Dye lasers should adhere to standards specified by the International Standards Organization (ISO), World Health Organization (WHO), and the Society of Photo-Optical Instrumentation Engineers (SPIE).