The Laser

Before understanding laser lasers, you need to know the information on light (because the laser is made of laser). The light from the sun and light bulbs is called white light. It is actually a mixture of all different colors of light. The colors range from violet, indigo, blue to green, yellow, orange, and red. These constitute the visible part of the electromagnetic spectrum. Light consists of particles called PHOTONS. The difference in color depends on the wavelength of light.

Laser surgery: The use of lasers during brain surgery is a relatively routine way. The purpose of laser surgery is to destroy the laser beam at the cancer with heat. Because the beam can not penetrate the bone, the laser can only be used during surgery. Lasers are used in addition to or in lieu of females. The laser generates very large heat and power when focusing on close range. Laser destroys tumor cells by evaporating tumor cells. Stereotactic techniques or computer aided techniques are often used to guide the laser. The laser is primarily used to treat tumors infiltrating the bottom of the skull or deep within the brain.

A commercially available laser diode emits light at a wavelength from 375 nm to 3500 nm. Medium and low power laser diodes are used in laser pointers, laser printers, and CD / DVD players. Laser diodes are also often used to efficiently pump other lasers optically. Industrial laser diodes with maximum output up to 20 kW are used in the industry for cutting and welding. An external resonator type semiconductor laser has a semiconductor active medium in a larger resonator. These devices produce high power with excellent beam quality, wavelength tunable narrow linewidth radiation, or ultrashort laser pulses.

A vertical cavity surface emitting laser (VCSEL) is a semiconductor laser that radiates in a direction perpendicular to the surface of a wafer. VCSEL devices typically have a rounded output beam than conventional laser diodes. As of 2005, only 850 nm VCSELs are commercially available, 1300 nm VCSELs have been commercialized, and 1550 nm devices are being studied. VECSEL is the external resonator VCSEL. Quantum cascade lasers are semiconductor lasers with effective transitions between the energy subbands of electrons in structures containing several quantum wells.

Lasers radiating in the green part of the spectrum are widely available in a wide range of outputs in general. A green laser pointer with an output of 532 nm (563.5 THz) is relatively inexpensive compared to other wavelengths of the same output and is very popular due to its good beam quality and very high apparent brightness doing. The most common green laser uses diode-pumped solid (DPSS) technology to generate green light. Crystals of yttrium doped lanthanum vanadium oxide (Nd: YVO 4) or yttrium doped yttrium aluminum garnet (Nd: YAG) were excited using an 808 nm infrared laser diode to emit 281.76 THz (1064 nm). This deeper infrared light passes through another crystal containing potassium, titanium, phosphorus (KTP). Due to its nonlinearity, twice the frequency of the incident beam (563.5 THz) occurs. The wavelength is 532 nm ("green")