An Er:glass laser (erbium-doped glass laser) is a solid-state laser whose active laser medium is erbium-doped glass. Ytterbium (Yb) is sometimes added to these lasers to improve their efficiency. Er:glass lasers emit light in the infrared region of the electromagnetic spectrum, often in the range of 1530–1560 nanometers. [1]
The specific wavelengths that Er:glass produces (approximately 1500 nanometer) coincide with a strong absorption peak for water. Since the human cornea and lens contain a high water content, they effectively absorb the laser radiation, thereby reducing the amount of light transmitted to the retina. The retina is the light-sensitive layer of the eye and is particularly vulnerable to damage from high-powered lasers. Consequently, Er:glass lasers are classified as relatively eye-safe compared to lasers operating at wavelengths that reach the retina. This relative eye safety allows Er:glass lasers to be used in many different applications where eye safety is preferable or necessary, such as in medicine and in public areas. [1] [2]
In addition to being relatively eye-safe, the 1500 nanometer wavelength that Er:glass lasers produce is also an ideal wavelength for laser rangefinders. It offers good transparency in the atmosphere, allowing the beam to travel long distances with minimal degradation. Additionally, this wavelength coincides with the peak sensitivity of certain infrared photodetectors that can operate at room temperature (including both indium gallium arsenide (InGaAs) and germanium (Ge)-based photodiodes). [1] [3]
The Er:glass lasers used in rangefinders typically emit short, high-energy pulses (Q-switched pulses) ranging from 1 to 10 millijoules. These lasers can measure distances up to 10 kilometers. The repetition rate, which refers to the frequency at which these pulses are emitted, depends on the pumping mechanism. Flash-lamp-pumped devices without active cooling can only produce pulses every few seconds. In contrast, diode-array pumped systems offer much faster repetition rates, reaching up to 10–20 hertz range. [1] [2]
Er:glass lasers are used for non-ablative laser skin resurfacing procedures, such as Fraxel Restore. The 1540 nanometer wavelength is highly absorbed by water molecules within the skin tissue. This absorption heats the water molecules, creating controlled thermal damage (thermolysis) in the upper dermis. This thermal damage stimulates the skin's natural wound healing response, promoting the production of new collagen fibers. By stimulating collagen production, Er:glass laser treatment aims to improve the appearance of fine lines, wrinkles, and uneven skin tone without completely removing the top layers of skin. This approach is considered to be a gentler alternative to ablative laser resurfacing techniques, typically resulting in shorter healing times and a reduced risk of scarring. [4] [5] [6]
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word laser is an anacronym that originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow.
A laser is constructed from three principal parts:
Ultraviolet (UV) light is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights.
An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed. Optical amplifiers are important in optical communication and laser physics. They are used as optical repeaters in the long distance fiber-optic cables which carry much of the world's telecommunication links.
A laser diode is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction.
A dye laser is a laser that uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths, often spanning 50 to 100 nanometers or more. The wide bandwidth makes them particularly suitable for tunable lasers and pulsed lasers. The dye rhodamine 6G, for example, can be tuned from 635 nm (orangish-red) to 560 nm (greenish-yellow), and produce pulses as short as 16 femtoseconds. Moreover, the dye can be replaced by another type in order to generate an even broader range of wavelengths with the same laser, from the near-infrared to the near-ultraviolet, although this usually requires replacing other optical components in the laser as well, such as dielectric mirrors or pump lasers.
A flashtube (flashlamp) is an electric arc lamp designed to produce extremely intense, incoherent, full-spectrum white light for a very short time. A flashtube is a glass tube with an electrode at each end and is filled with a gas that, when triggered, ionizes and conducts a high-voltage pulse to make light. Flashtubes are used most in photography; they also are used in science, medicine, industry, and entertainment.
The vertical-cavity surface-emitting laser is a type of semiconductor laser diode with laser beam emission perpendicular from the top surface, contrary to conventional edge-emitting semiconductor lasers which emit from surfaces formed by cleaving the individual chip out of a wafer. VCSELs are used in various laser products, including computer mice, fiber optic communications, laser printers, Face ID, and smartglasses.
Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, neodymium in the +3 oxidation state, Nd(III), typically replaces a small fraction (1%) of the yttrium ions in the host crystal structure of the yttrium aluminum garnet (YAG), since the two ions are of similar size. It is the neodymium ion which provides the lasing activity in the crystal, in the same fashion as red chromium ion in ruby lasers.
Laser radiation safety is the safe design, use and implementation of lasers to minimize the risk of laser accidents, especially those involving eye injuries. Since even relatively small amounts of laser light can lead to permanent eye injuries, the sale and usage of lasers is typically subject to government regulations.
Yttrium aluminium garnet (YAG, Y3Al5O12) is a synthetic crystalline material of the garnet group. It is a cubic yttrium aluminium oxide phase, with other examples being YAlO3 (YAP) in a hexagonal or an orthorhombic, perovskite-like form, and the monoclinic Y4Al2O9 (YAM).
An Er:YAG laser (erbium-doped yttrium aluminium garnet laser, erbium YAG laser) is a solid-state laser whose active laser medium is erbium-doped yttrium aluminium garnet (Er:Y3Al5O12). Er:YAG lasers typically emit light with a wavelength of 2940 nm, which is infrared light.
A solid-state laser is a laser that uses a gain medium that is a solid, rather than a liquid as in dye lasers or a gas as in gas lasers. Semiconductor-based lasers are also in the solid state, but are generally considered as a separate class from solid-state lasers, called laser diodes.
This is a list of acronyms and other initialisms used in laser physics and laser applications.
A ruby laser is a solid-state laser that uses a synthetic ruby crystal as its gain medium. The first working laser was a ruby laser made by Theodore H. "Ted" Maiman at Hughes Research Laboratories on May 16, 1960.
Photorejuvenation is a skin treatment that uses lasers, intense pulsed light, or photodynamic therapy to treat skin conditions and remove effects of photoaging such as wrinkles, spots, and textures. The process induces controlled wounds to the skin. This prompts the skin to heal itself, by creating new cells. This process—to a certain extent—removes the signs of photoaging. The technique was invented by Thomas L Roberts, III using CO2 lasers in the 1990s. Observed complications have included scarring, hyperpigmentation, acne, and herpes.
Fraxel Laser Treatment is a line of lasers developed by Reliant Technologies in 2004. It was developed from a US patent licensed from the Wellman Center for Photomedicine. R. Rox Anderson was the inventor. Fraxel lasers cause fractional photothermolysis for skin resurfacing.
Radio-frequency skin tightening is an aesthetic technique that uses radio frequency (RF) energy to heat skin with the purpose of stimulating cutaneous collagen, elastin and hyaluronic acid production in order to reduce the appearance of fine lines and loose skin. The technique induces tissue remodeling and production of new collagen and elastin. The process provides an alternative to facelift and other cosmetic surgeries.
A Pr:YLF laser (or Pr3+:LiYF4 laser) is a solid state laser that uses a praseodymium doped yttrium-lithium-fluoride crystal as its gain medium. The first Pr:YLF laser was built in 1977 and emitted pulses at 479 nm. Pr:YLF lasers can emit in many different wavelengths in the visible spectrum of light, making them potentially interesting for RGB applications and materials processing. Notable emission wavelengths are 479 nm, 523 nm, 607 nm and 640 nm.
Laser-assisted drug delivery (LADD) is a drug delivery technique commonly used in the dermatology field that involves lasers. As skin acts as a protective barrier to the environment, the absorption of topical products through the epidermis is limited; thus, different drug delivery modalities have been employed to improve the efficacy of these treatments. The use of lasers in LADD has been shown to enhance the penetration of drugs transdermal, leading to a higher absorption rate, limited systemic effects, and reduced duration of treatment. Although this technique has evolved in the past decade due to its efficacy through scientific research and clinical practice, there remain some limitations regarding the safety aspect that needs to be taken into consideration.