Lasers are used in practically every major industry, from medicine and computers to entertainment and construction. A power rating, usually in watts, determines the strength of the laser. Some can cut through metal, while others read tiny bits of information without damaging the surface. Basically, the applications can be divided into marking, etching, and cutting, or reading and scanning.
In the medical industry, carbon dioxide lasers are used in many types of surgery because they are more precise and sensitive than scalpels. They can be used to remove tattoos without needing skin grafts, as well as to painlessly clear rot out of teeth. When used for surgery, they are often less invasive, which means that the patient often recuperates more quickly. A laser can be used to remove certain types of tumors or to correct a patient's vision by reforming the lens of the eye. Damage to surrounding tissue, as well as bleeding, can also be reduced.
Many common home or office devices include lasers as an intrinsic part of their performance. CD, DVD and Blu-ray™ players use the light to read the audio and video information on the disc, the way a needle used to read the groove of a record. Recorders have stronger lasers that can burn the information onto the surface of the disc, either temporarily or permanently. They are also used in laser printers to change a surface, in this case paper, to display text and graphics. Even at the grocery store, they're used to scan the barcode on packages to tell the computerized register what a shopper is buying and how much it costs.
Lasers of the appropriate strength can etch surfaces from plastic to rock. Some companies inscribe a minute identification number on diamonds to keep track of them. Tombstones made of granite or limestone are carved with powerful lasers. Many metal pieces can be precisely cut out, drilled, and welded together to make a finished product using ones capable of melting metal.
Even though the first laser was made in a laboratory back in 1960, it took several decades to apply this tool to various technologies. Now, lasers are indispensable to most people's daily lives. Visible ones have even replaced strings, levels, and stakes in surveying equipment. A laser show inside a planetarium uses colored lights of all widths simulate the night sky.