A broad range of laser are present and its usage isdepends upon the field. Laser iscategorized in main modules on the basis of medium used to generate laser.Depending upon the medium the range and wavelength also vary.Main categories of laser are:1. GAS laserIt is further divided into subcategories that are:· Helium neon laser:Argonis a noble gas and wave length of this laser is 632.8 nm and its application isin retailing stores is bar code scanning. It is also used in spectroscopy· Argon laser:Operatingwavelength of this laser are 454.
6 nm, 514.5 nm, 514.5 nm and used in retinalphotography and other field for pumping other lasers.· Krypton laser:Possiblewavelengths are between 416nm to 799.
3 nm and applied in scientific researchand with the combination of organ it gives white light.· Nitrogen laser:Itis 337.1nm of wavelength and source is electrical discharge mostly applicablein the field of environmental measurement like air pollution measurement.
· Carbon dioxide laser:Itis 2.6, 4.8 or 8.
3 nm long. Used in welding and spectroscopy.2. Chemicallase· Deuterium fluoride laserThemaximum wavelength is 4.2 ?m andits pumping source is chemical reactions and applicable in military areasmostly.
· Chemical oxygen iodine laser:Itis used in military, scientific and material research and of 1.315 ?m .3. DyelaserDye laser have broad applicationsin medical to remove birthmarks. Use in separation isotopes of atoms. Also usedin medicines and spectroscopy.
4. Solidstate laser· Ruby laserThemain source is flash lamp and have wavelength of 694.3nm.
Area of interest istattoo removal and holography.· In dental treatment Er:YAG laser is usedwith 1.0470and 1.053?mwavelength.· For theproduction of Nano powders a laser known as NdCrYAD is preferable.
5. SemiconductorlaserSome people also called it diodelaser and the devices use in this technology is small and consume low power.6. Metalvapors laser· HeCd laser:325nmor 441.
563 nm and used in printing scientific work and enhance flouricnce.· HeHg laser:Heliummercury laser is useful in construction of amateur laser and scientific areas.· In scientific scenario other importantlaser are Helium silver, strontium vapors, neon copper and some othercombination of noble gases with metals. 7. Someother types of laser· Free election laser is used inatmosphere and material science.
· Gas dynamic laser has the impact inheavy industry.· Nuclear pump laser are emitted to applyin weapons and research.These are the types oflaser categorized on the basis of medium they also can be grouped in certaintype on the basis of other factors as well like the duration of the emission.Some laser are emittedcontinuously while some are single pulsed.
Some laser are repeating in natureand few of them are mode locked.so on the basis of the duration the havedifferent ranges of power as well.