A wide range of laser is exists and its usagedepends upon the field.

  Laser iscategorized in main modules on the foundation of medium used to produce 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:Heliumis a noble gas with wave length is 632.8 nm and preferably used in bar codescanning and in spectroscopy·        Argon laser:Thistype of laser has wavelengths values 454.6 nm, 514.

5 nm, 514.5 nm. It has givengood results in retinal photography.

Moreover it is the best for pumping the otherlasers.·        Krypton laser:Thislaser has range of values from 416nm to 799.3 nm.it is found very helpful inscientific research and you can have white light when you combine it with Argon.

·        Nitrogen laser:Ithas wavelength 337.1nm. You can easily get it from electrical discharge. It ismostly used in measurement of environmental pollution.

·        Carbon dioxide laser:Thislaser has values of wavelengths 2.6, 4.8 or 8.3 nm.

Its application is found I  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.      Dyelaser:Dye laser have broadly used inmedical to remove birthmarks. Also use in categorized isotopes of atoms, inmedicines and spectroscopy.4.

      Solidstate laser·        Ruby laser:Itis emerged from flash lamp and have wavelength of 694.3nm. mostly used intattoo removal and holography.·        For dental treatment Er:YAG laser isused with 1.0470and 1.053?mwavelength.·        For theproduction of Nano powders a laser known as NdCrYAD is preferable.

   5.      SemiconductorlaserSome people also called it diodelaser. Gadgets 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.

 Theseare the kinds of laser sorted based on medium they can be gathered in certainkind based on different factor like the source that discharge them.Some type of laserare emitted continuously while some are single pulsed. Some lasers arerepeating in nature and few of them are mode protected.

So on the basis of theduration the have different ranges of power as well.