Lasers
A.N.


The Laser Concept was developed by Charles Townes and Arthur Schawlow. The laser began as a Maser (Microwave Amplification by Stimulated Emission of Radiation). By 1950, scientists had researched and proposed designs to amplify light instead of microwaves. Some of these people were Charles Townes, Arthur Schawlow, Alexander Prokhorov, Nikolai Basov, and Gordon Gould.

In 1960, Theodore Maiman of the United States, constructed the first laser. He used a ruby rod as it's active medium. Later that year, the first gas laser was invented, and in 1962, American scientists operated the first semiconductor laser.

A typical laser has three main parts. They are an active medium, an energy source, and an optical cavity. The active medium is the material that creates the laser light. Some materials that can be used for an active medium are liquids, solids, gases, plasmas, and electrons.

Lasers often use electric power as an energy source, along with other lasers, and a flash lamp. The energy source delivers energy to the active medium through a process called pumping.

The optical cavity, also known as a resonator, houses the active medium. Usually the resonator has two mirrors. One of the mirrors has a fully reflecting surface, while the other has only a partially reflecting surface. The photons (lights particles) reflect off of the fully reflecting mirror, and exit the laser, through the partially reflecting mirror, as a laser beam.

Atoms within the active medium are excited and release photons, and photons hitting other atoms are absorbed and doubled (basically), increasing the amount of light. The now doubled amount of photons, increases again and again, while other photons exit the laser. Because not all photons exit the laser, the amount of photons can continue to increase as long as the energy source is active.

Lasers can be used for many things. Lasers can be used for measurement of distance, surgery, precision cutting, and for sending information.

By placing laser receptors in a straight line from a laser and releasing the laser beam, you can find the distance between the laser and the receptors with the formula "D = RT".

Lasers are useful in certain types of surgery. Lasers can cut tumors, by burning and weakening the cells, therefore killing them. Lasers can also help correct eyesight.

Lasers used in factories usually cut metal or other objects. Because laser light is so precise, you can cut objects with extreme accuracy, and therefore allowing parts for machines and tools to be exact with the machine or tool's requirements.

Lasers used for sending information can be very useful. Data encoded in lasers can be transmitted at the speed of light to machines or people that need it. Since lasers are light, the data can be directed into receivers by mirrors if a straight path is not available. Lasers are very interesting, and to delve deeper into how they work and why they work, you have to understand how atoms can be stimulated, along with what photons are and their qualities. Lasers may have a big part in the future, and if they do, it is best to begin to understand them now.


Return to 7th Grade Inventions Main Page